WO2006130471A1 - The use delta opioid receptor agonists and/or inverse agonists to inhibit the consumption of substances of abuse - Google Patents

Abstract

This invention provides compounds and methods that inhibit one or more components of behavior associated with substance abuse. In certain embodiments it is shown that compounds SoRI9409 and SoRI20411 inhibit consumption of a substance of abuse (e.g., ethanol).

Description

THE USE OF DELTA OPIOID RECEPTOR AGONISTS AND/OR

INVERSE AGONISTS TO INHIBIT THE CONSUMPTION OF

SUBSTANCES OFABUSE

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to and benefit of USSN 60/685,576, filed on May 27, 2005 which is incorporated herein by reference in its entirety for all purposes.

STATEMENT AS TO RIGHTS TO INVENTIONS MADE UNDER FEDERALLY SPONSORED RESEARCH AND DEVELOPMENT

[ Not Applicable ]

FIELD OF THE INVENTION [0002] This invention pertains to the field of addiction. Particular compounds are identified that inhibit consumption of substances of abuse (e.g., ethanol).

BACKGROUND OF THE INVENTION

[0003] The abuse of ethanol and other "addictive substances" remains a major public health problem in the U.S. and throughout the world. Drug dependency is extremely difficult to escape. This is true whether the dependency is one based on ethanol, amphetamine, barbiturates, benzodiazepines, cocaine, nicotine, opioids, and phencyclidine or the like.

[0004] Alcoholism is the most common form of drug abuse and a major public health problem worldwide. Nevertheless, few drugs exist that modify alcohol intake and the genetic factors that influence alcohol's effects on brain and behavioral processes remain largely uncharacterized. Thus, there is a need for diagnostic tests that can identify individuals with a predisposition to becoming alcoholics and a need for treatments that can alter alcohol consumption.

[0005] The Lewin Group estimated the economic cost to U.S. society in 1992 due to alcohol and drug abuse to be $246 billion, $148 billion of which was attributed to alcohol abuse and alcoholism and $98 billion of which stemmed from drug abuse and dependence (Harwood et al, The Economic Costs of Alcohol and Drug Abuse in the United States, 1992, NIH Publication Number 98-4327 (September 1998)). When adjusted for inflation and population growth, the alcohol estimates for 1992 are very similar to cost estimates produced over the past 20 years, and the drug estimates demonstrate a steady and strong pattern of increase. The current estimates are significantly greater than the most recent detailed estimates developed for 1985 for alcohol and for drugs (Rice et al. 1990)~42 percent higher for alcohol and 50 percent greater for drugs over and above increases due to population growth and inflation

[0006] The study of compounds exerting their actions via the opioid receptor system has continued for quite some time (Aldrich (1996) Analgesics. In Burger's Medicinal Chemistry and Drug Discovery, Vol. 3, Wolff, M. E. Eds.; John Wiley & Sons: New York). Though this has been a broad effort, the fundamental driving force for this endeavor relates to the elimination or reduction of the side-effect profile produced by the most frequently used or abused opiates morphine and heroin. The wealth of knowledge accumulated in this time is enormous and includes examples ranging from the original concept of an opiate receptor (Pert and Snyder (1973) ScienceY19: 1011-1014) to the more recent cloning of individual opioid receptor subtypes, e.g., μ (mu) (Chen et al. (1993) MoI. Pharmacol., 44: 8-12; Thompson et al. (1993) Neuron, 11(5): 903-913; Wang et al. (1994) FEBS Lett., 338: 217-222), δ (delta) (Keiffer et al. (1992) Proc. Natl Acad. ScL U.S.A. 89:12048-12052; Evans et al. (1992) Science, 258: 1952-1955), and K (kappa) (Meng et al. (1993) Proc Natl Acad Sd USA, 90(21): 9954-9958; Minami et al. (1993) FEBS Lett, 329(3): 291-295; Nishi et al. (1993) FEBS Lett, 330(1): 77-80). Belonging to the superfamily of G protein-coupled receptors (GPCR), postulated to possess seven helical transmembrane (7TM) spanning regions, they are now known to be anatomically distributed in both the central and peripheral nervous systems and aside from modulation of pain are intimately involved in a diversity of biological events ranging from of the modulation of immune response (Nunez and Urzua (1999) Rev. Med. ChU., 127(3): 341-348; Bruce et al. (1996) Pharmacol Biochem. Behav., 53(4), 885-889; Volpicelli et al. (1992) Arch. Gen. Psychiatry, 49:876- 879). [0007] While there is an extensive literature describing the effects of substances of abuse on opioid receptors, to date, the use of opioid receptor antagonists and/or agonists has not achieved satisfactory regulation of behaviors associated with substance abuse.

SUMMARY OF THE INVENTION

[0008] This invention pertains to the discovery that agents with particular agonistic activities on opioid receptors can be administered to a mammal (e.g., a human) to inhibit one or more behaviors associated with chronic consumption of a substance of abuse, and/or cessation of such chronic consumption and/or withdrawal. In particular, it was a surprising discovery that a first class of agents that are agonists at mu and delta opioid receptors when they are expressed alone or when the mu and delta opioid receptors are expressed together in cell lines (e.g., SoRI 20144) decrease consumption of a substance of abuse (e.g., alcohol) and also induce/promote weight loss.

[0009] Thus, in certain embodiments, this invention provides a method of mitigating one or more components of addictive behavior associated with chronic consumption of a substance of abuse, and/or withdrawal therefrom, and/or cessation of consumption of a substance of abuse by a mammal (e.g., a human). The method typically involves administering to the mammal: a first agent that is an agonist at mu and delta opioid receptors when they are expressed alone or when the mu and delta opioid receptors are expressed together in cell lines; and/or a second agent that is an agonist only when the mu and delta opioid receptors are expressed together but not when they are expressed alone. In certain embodiments the first agent and said second agent are not naloxone and/or a naloxone derivative. In various embodiments the second agent is an inverse agonist at delta opioid receptors when these receptors are expressed alone. In certain embodiments the first agent or the second agent is selected from the group consisting of SNC 80 [(+)-4-[(alphaR)- alpha-((2S,5R)-4-Allyl-2,5-dimethyl-l-ρiperazinyl)-3-methoxybenzyl]-N,N- diethylbenzamide], TIPP, Dmt-Tic-OH, N,N(CH3)2-Dmt-Tic-NH₂, Tan67, [D-Pen(2,5)]- enkephalin, DPDPE, H-Try-d-Ala-Phe-Glu- VaI-GIy-NH₂, Deltorphin II, BUBU, deltorphin I, [D-Met²] -deltorphin, 3,4-dimethyl-4-(3-hydroxyphenyl)piperidines derivatives (i.e. LY515300 and its derivatives), H-Tyr-TicPsitCffiNJCha-Phe-OH, (TΙCP(Psi)), 2',6 - dimethyltyrosine-l,2,3,4-tetrahydroquinoline-3-carboxylate (Dmt-Tic) peptides, ICI- 174,864, SoRI 9409, SoRI 20411, and SoRI 2404. In certain embodiments the first agent or second agent is selected from the agents of any one of Tables 1 through 5. In various embodiments the first agent and/or second agent is administered in conjunction with a delta opioid receptor antagonist. The agent(s) can be formulated with a pharmacologically acceptable excipient and/or provided as a unit dosage formulation. In various embodiments the substance of abuse is ethanol, an opiate, a cannabinoid, nicotine, or a stimulant. In various embodiments the substance of abuse is morphine, heroin, marijuana, hashish, cocaine, or an amphetamine. In certain preferred embodiments the substance of abuse is ethanol.

[0010] Various components of "addictive" behavior that can be mitigated by the methods of this invention include chronic self-administration of a substance of abuse, craving for the substance of abuse, reinstatement of seeking behavior for the substance of abuse. The methods can be applied to a subject engaging in chronic consumption of a substance of abuse and/or to a subject that has ceased chronic consumption of a substance of abuse, and/or to a subject undergoing one or more symptoms of withdrawal. In certain embodiments the methods comprise reducing self-administration of alcohol. In various embodiments the first agent comprises SoRI 20144 and/or a derivative thereof and the second agent comprises SoRI 9409 and/or a derivative thereof.

[0011] Also provided herein are kits for inducing and/or promoting weight loss and/or for mitigating one or more components of addictive behavior associated with chronic consumption of a substance of abuse, and/or cessation of such consumption, and/or withdrawal therefrom, by a mammal (e.g., a human). The kits typically comprise a container containing one or more first agent(s) and/or one or more second agent(s) as described herein. The agents can be in separate containers, in the same container, and or formulated as a combined single formulation. In certain embodiments the kit additionally comprises a delta opioid receptor antagonist. The agent(s) can be formulated with a pharmacologically acceptable excipient and/or in a unit dosage formulation.

[0012] The kits, optionally, additionally comprise instructional materials teaching the use of the agent(s) for the treatment of substance abuse (e.g., to inhibit consumption of alcohol) and/or to induce and/or promote weight loss. In certain embodiments the kits comprise SoRI 20144 and/or a derivative thereof and/or SoRI 9409 and/or a derivative thereof. [0013] Also provided is a method of screening for an agent that inhibits consumption of alcohol (or other substances of abuse) and/or that promotes and/or induces weight loss. The method typically involves screening a test agent for a first agonist activity at mu and delta opioid receptors when they are expressed alone or when the mu and delta opioid receptors are expressed together in cell lines; and/or a second agonist activity only when the mu and delta opioid receptors are expressed together but not when they are expressed alone; and where agents that show said first agonist activity and/or said second agonist activity are putative agents for inhibiting consumption of alcohol and/or for promoting/inducing weight loss. In certain embodiments the agents have inverse agonist activity at the delta opioid receptor when these receptors are expressed alone. In certain embodiments the method comprises screening cells that are transfected to express a heterologous mu opioid receptor and/or a heterologous delta opioid receptor. In certain embodiments the method comprises measuring phosphorylation of the receptor and/or c AMP levels.

[0014] In various embodiments this invention also pertains to the discovery that delta opioid receptor antagonists can delay the development of tolerance to the antinociceptive effect of an opiate analgesic. Accordingly, this invention also provides a method of delay the development of tolerance to the antinociceptive effect of an opiate analgesic where the method involves administering a delta opioid receptor antagonist in conjunction with the opiate analgesic. In various embodiments the opiate analgesic is selected from the group consisting of a natural opium alkaloid, a phenylpiperidine derivative, a diphenylpropylamine derivative, a benzomorphan derivative, an oripvaine derivative, and a morphinan derivative. In certain embodiments the opiate analgesic is selected from the group consisting of morphine, opium, hydromorphone, nicomorphine, oxycodone, dihydrocodeine, diamorphine, papaveretum, codeine, ketobemidone, pethidine, fentanyl, dextromoramide, piritramide, dextropropoxyphene, bezitramide, dextropropoxyphene, pentazocine, phenazocine, buprenorphine, butorphanol, nalbufine, tilidine, tramadol, and dezocine. Suitable delta opioid receptor antagonists include, but are not limited to 3,4-dimethyl-4-(3-hydroxyphenyl)ρiperidine derivative {i.e. LY515300 and its derivatives), H-Tyr-TicPsi[CH2N]Cha-Phe-OH, (TICP(Psi)), 2',6'-dimethyltyrosine- l,2,3,4-tetrahydroquinoline-3-carboxylate (Dmt-Tic) peptides, ICI-174,864, SoRI 9409, LY255525, 6 beta naltrexol, naltrexamide, and the like. In various embodiments the delta opioid receptor antagonist can be administered prior to, simultaneously with, or after the opiate analgesic. In certain embodiments the delta opioid receptor antagonist and the opiate analgesic are provided as a single unit dosage formulation.

[0015] Also provided is a a pharmaceutical composition comprising a delta opioid receptor antagonist and an opiate analgesic. In various embodiments the opiate analgesic includes, but is not limited to, a natural opium alkaloid, a phenylpiperidine derivative, a diphenylpropylamine derivative, a benzomorphan derivative, an oripvaine derivative, and a morphinan derivative. . In various embodiments the opiate analgesic includes, but is not limited to, morphine, opium, hydromorphone, nicomorphine, oxycodone, dihydrocodeine, diamorphine, papaveretum, codeine, ketobemidone, pethidine, fentanyl, dextromoramide, piritramide, dextropropoxyphene, bezitramide, dextropropoxyphene, pentazocine, phenazocine, buprenorphine, butorphanol, nalbufine, tilidine, tramadol, dezocine, and the like. Suitable delta opioid receptor antagonists include, but are not limited to 3,4-dimethyl- 4-(3-hydroxyphenyl)piperidine derivative (i.e. LY515300 and its derivatives), H-Tyr- TicPsi[CH2N]Cha-Phe-OH, (TΙCP(Psi)), 2',6'-dimethyltyrosine-l ,2,3,4- tetrahydroquinoline-3-carboxylate (Dmt-Tic) peptides, ICI- 174,864, SoRI 9409, LY255525, 6 beta naltrexol, and naltrexamide. In various embodiments the composition is formulated as a unit dosage formulation. Suitable formulation include, but are not limited to a transdermal formulation, a sustained release formulation, and oral formulation, an injectable formulation, and the like. [0016] In various embodiments this invention also provides a method of mitigating psychological or physical dependence on a substance of abuse by a mammal. The method typically involves administering to the mammal a delta opioid receptor antagonist in an amount sufficient to mitigate psychological or physical dependence on the substance of abuse. In certain embodiments the substance of abuse is an agent such as ethanol, an opiate, a cannabinoid, nicotine, a stimulant, and the like. In certain embodiments the substance of abuse is an agent such as morphine, heroin, marijuana, hashish, cocaine, amphetamines, and the like. In certain embodiments the substance of abuse is alcohol. Suitable delta opioid receptor antagonist include, for example, those listed above. In certain embodiments the delta opioid receptor antagonist is selected from the group consisting SoRI 9409, LY255525, 6 beta naltrexol, and naltrexamide. In various embodiments the mammal is a mammal engaging in chronic consumption of a substance of abuse. In various embodiments the mammal is a mammal that has ceased chronic consumption of a substance of abuse. In typical embodiments, the mammal is a human. In certain embodiments the human is a human enrolled in a 12-step program.

DEFINITIONS

[0017] The term "substance of abuse" typically refers to a substance that is psychoactive and that induces tolerance and/or addiction. Substances of abuse include, but are not limited to stimulants (e.g., cocaine, amphetamines), opiates (e.g., morphine, heroin), cannabinoids (e.g., marijuana, hashish), nicotine, alcohol, substances that mediate agonist activity at the dopamine D2 receptor, and the like. Substances of abuse include, but are not limited to addictive drugs. In the case of addictive over-consumption, food, sugar, and the like can be considered a substance of abuse. When "ethanol" is referred to as a substance of abuse it is intended to include ethanol itself as well as a food or drink containing ethanol.

[0018] The phrase "in conjunction with" when used in reference to the use of one or more agents as described herein (e.g., agonists at the mu and/or delta opiod receptor) indicates that the two agents are administered so that there is at least some chronological overlap in their physiological activity on the organism. Thus the two agents can be administered simultaneously and/or sequentially. In sequential administration there may even be some substantial delay (e.g., minutes or even hours or days) before administration of the second agent as long as the first administered agent has exerted some physiological alteration on the organism when the second administered agent is administered or becomes active in the organism.

[0019] The term "treat" when used with reference to treating, e.g., a pathology or disease refers to the mitigation and/or elimination of one or more symptoms of that pathology or disease, and/or a reduction in the rate of onset or severity of one or more symptoms of that pathology or disease, and/or the prevention of that pathology or disease. [0020] The term "inverse agonist" refers to a substance that inhibits constitutive activity of the receptor, suggesting that this substance is not technically an antagonist but an agonist with a negative intrinsic activity.

[0021] The phrase "promote weight loss" refers to inducing weight loss and/or to increasing the efficacy of dieting and/or exercise in producing weight loss in a mammal. [0022] A "delta opioid receptor antagonist" is an agent that shows antagonistic activity at the delta opioid receptor. A "preferential delta opioid receptor antagonist" is an agent that shows greater antagonistic activity at a delta opioid receptor than at other opioid receptors. A "specific delta opioid receptor antagonist" is an agent that shows at least 2- fold, preferably at last 5-fold, more preferably at least 10-fold, 20-fold, or 50-fold, and most preferably at least 100-fold, 500-fold, or 1000-fold greater antagonistic activity at a delta opioid receptor than at other opioid receptors.

BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 illustrates the structures of morphine, naltrexone, naltrindole, and

SoRI 9409. [0024] Figures 2A and 2B show that SoRI 9409 inhibits the intake of ethanol not water. SoRI9409 (5-30mg/kg) significantly reduced ethanol (Figure 2A) consumption but not (Figure 2B) water consumption in rats. Ethanol and water consumption (mean±sem) were measured using a free access 2 bottle choice paradigm (n=10 for each group, ** p<0.05). [0025] Figure 3 shows that SoRI 9409 inhibits the preference for ethanol compared with water. SoRI9409 (5-30mg/kg) significantly reduced ethanol preference in rats (n=10 for each group, ** p<0.05). Ethanol preference (%) was calculated as the mis. of ethanol consumed divided by the total fluid consumption (mis. of EtOH + mis. of water) using a free access 2 bottle choice paradigm. [0026] Figures 4A, 4B, 4C show that SoRI 20411 inhibits the intake of ethanol not water. SoRI 20411 (1-15 mg/kg) significantly reduced ethanol consumption (Figure 4A) and (Figure 4B) water consumption (15mg/kg) in rats. Ethanol and water consumption (mean±sem) were measured using a free access 2 bottle choice paradigm (n=10 for each group, ** p<0.05). Ethanol and water consumption (mean±sem) were measured using a free access 2 bottle choice paradigm. Figure 4C: SoRI 20411 (5-10mg/kg) inhibited ethanol preference in rats (n=10 for each group) but SORI 20422 (15mg/kg) did not inhibit preference for ethanol (n=10 for each group). Ethanol preference (%) was calculated as the mis. of ethanol consumed divided by the total fluid consumption (mis. of EtOH + mis. of water) using a free access 2 bottle choice paradigm. [0027] Figure 5 shows the results for morphine tolerance development in rats. Mean

(± SEM) degree of tail flick antinociception (% MPE) versus time for rats co-administered chronic morphine with either naltrexone, SoRI 9409 or saline, and for rats administered SoRI 9409 or naltrexone, with saline.

[0028] Figure 6 shows the effects of Naltrexone (1 mg/kg) after a period of extinction. Naltrexone was administered s.c. 30 minutes before the start of the daily operant self administration session (FR3). Values are means +/- s.e.m. (n=8 beer, n=9 nr beer, n=9 sucrose, n=7 EtOH) Significance testing was done by paired t-test.

[0029] Figure 7 shows the effect of SoRI 9409 (5 mg/kg) after a period of extinction. SoRI 9409 (δ-opioid receptor antagonist) was administered i.p. 30 minutes before the start of the daily operant self administration session (FR3). Values are means +/- s.e.m. (n=8 beer, n=9 nr beer, n=9 sucrose, n=7 EtOH) Significance testing was done by paired t-test.

[0030] Figure 8 shows the effect of naltrexone (lmg/kg) after a period of home cage deprivation. Naltrexone was administered s.c. 30 minutes before the start of the daily operant self administration session (FR3). Values are means +/- s.e.m. (n=3 beer, n=6 nr beer).

[0031] Figure 9 shows the effect of SoRI 9409 (5mg/kg) after a period of home cage deprivation. SoRI 9409 (δ-opioid receptor antagonist) was administered i.p. 30 minutes before the start of the daily operant self administration session (FR3). Values are means +/- s.e.m. (n=3 beer, n=6 nr beer)

DETAILED DESCRIPTION

[0032] This invention pertains to the discovery that agents with particular agonistic activities on opioid receptors can be administered to a mammal (e.g., a human) to inhibit one or more behaviors associated with chronic consumption of a substance of abuse, and/or cessation of such chronic consumption and/or withdrawal. In particular, it was a surprising discovery that a first class of agents that are agonists at mu and delta opioid receptors when they are expressed alone or when the mu and delta opioid receptors are expressed together in cell lines (e.g., SoRI 20144) decrease consumption of a substance of abuse (e.g., alcohol) and also induce/promote weight loss (see, e.g., Figure 4). [0033] It was also a surprising discovery that discovered that a second class of agents that are agonists (at mu and/or delta opioid receptors) only when the mu and delta opioid receptors are expressed together but not when they are expressed alone lines (e.g., SoRI 9409) decrease consumption of a substance of abuse (e.g., alcohol) and also induce/promote weight loss (see, e.g., Figures 2 and 3). The agonist activity only when mu and delta opioid receptors are co-expressed suggests that this second class of agents agonists at the mu/delta opioid receptor dimer complex. In certain embodiments such agents are also inverse agonists at delta opioid receptors when these receptors are expressed alone.

[0034] It was also a surprising discovery that both classes of agents are long acting and decrease, e.g., alcohol consumption after 16 and 24 hours. In contrast, naltrexone the standard treatment for alcoholism does not reduce drinking over the same time frame in our experiments.

[0035] In view of these discoveries, this invention provides methods of mitigating one or more components of addictive behavior associated with chronic consumption of a substance of abuse, and/or cessation of such consumption, and/or withdrawal therefrom, by a mammal (e.g., a human) where the method involves administering to the mammal one or of the first and/or second class of agents in an amount sufficient to ameliorate one or more components of addictive behavior (e.g., craving, seeking behavior, anxiety, chronic self- administration, etc.). In various embodiments the agent(s) are not naloxone and/or a naloxone derivitave and/or naltrexone and/or a naltrexone derivative. [0036] In another embodiment, this invention pertains to the discovery that delta opioid receptor antagonists can delay the development of tolerance to the antinociceptive effect of an opiate analgesic. Thus, in certain embodiments, this invention provides methods of inhibiting the development of such tolerance. The methods typically involve administering a delta opioid receptor antagonist in conjunction with the opiate analgesic. In addition this invention provides pharmaceutical compositions comprising a delta opioid receptor antagonist and an opiate analgesic.

[0037] It was also discovered that delta opioid receptors are implicated in dependence on a substance of abuse, thus inhibition of such receptors can mitigate psychological or physical dependence on said substance of abuse. [0038] Without being bound to a particular theory, it is believed that agents described herein can be effective in the treatment of addictive behaviors (addiction) to any of a wide variety of addictive substances (e.g., substances of abuse). Such substances include, but are not limited to stimulants (e.g., cocaine, amphetamines), opiates (e.g., morphine, heroin), cannabinoids (e.g., marijuana, hashish), nicotine, alcohol, substances that mediate agonist activity at the dopamine D2 receptor, and the like. In certain instances, food and/or sugar can be regarded as a substance of abuse (e.g., in compulsive eating disorders).

[0039] Typically one or more of the agents described herein will be administered to a mammal, more typically to a human to ameliorate one or more behaviors associated with addiction to a substance of abuse (e.g., dependence, craving, self administration, reinstatement, etc.)). Most typically, the agent(s) will be administered to reduce self administration and/or seeking behavior and/or to reduce cravings and/or anxiety, especially for alcohol and/or other substances of abuse. In certain embodiments, the subjects will be subjects that are not being treated for Parkinson's syndrome or other neurological disorders (other than those associated with addictive behavior).

[0040] In various preferred embodiments, the agent(s) are administered to reduce or prevent consumption of the substance of abuse (e.g. , alcohol) and/or to reduce cravings for the substance of abuse.

I. Active agents. [0041] It was surprising discovery that various active agents described herein are effective to mitigate/inhibit one ore more or more components of addictive behavior associated with chronic consumption of a substance of abuse. In certain embodiments the agents inhibit consumption/self administration of alcohol and/or other substances of abuse.

[0042] In various embodiments the agents include compounds that are agonists at mu and delta opioid receptors when they are expressed alone or when the mu and delta opioid receptors are expressed together in cell lines; and/or agonists only when the mu and delta opioid receptors are expressed together but not when they are expressed alone. In certain embodiments the agent(s) are inverse agonists at delta opioid receptors when these receptors are expressed alone. [0043] A wide variety of agents can be used in the methods of this invention. In certain embodiments the agents include, various pyridomorphinans. A number of suitable pyridomorphinans are described in U.S. Patent 6,465,479 (which is incorporated herein by reference in its entirety and particularly for the structures disclosed therein) and can be represented by Formula I:

where each of Y, X and R is individually selected from the group consisting of hydrogen, hydroxy, alkyl, alkoxy, aryl, halo, CF₃ and NO₂, provided that at least one of Y, X and R is other than hydrogen; and pharmaceutically acceptable salts thereof. In certain embodiments the alkyl groups typically contain 1 to about 6 carbon atoms, and more typically 1 to about 3 carbon atoms, and can be straight, branched-chain or cyclic saturated aliphatic hydrocarbon groups. Examples of suitable alkyl groups include methyl, ethyl and propyl. Examples of branched alkyl groups include isopropyl and t-butyl. Examples of suitable cyclic aliphatic groups typically contain 3-6 carbon atoms and include cyclopentyl and cyclohexyl. Suitable alkoxy groups preferably contain 1-6 carbon atoms and include methoxy, ethoxy, propoxy and butoxy. Examples of aryl groups include phenyl and naphthyl. Examples of halo groups include F, Cl, Br and I.

[0044] Some specific pyridomorphinans compounds are represented by the combinations of R, X and Y groups shown in Table 1.

[0045] Table 1. Illustrative combinations of R, X, and Y groups in Formula I.

R X Y

F H H

Br H H

I H H

CH₃ H H

CH₃O H H CF₃ H H

NO₂ H H

OH H H

C₆H₅ H H

H Cl H

H H Cl

Cl Cl H

Cl H Cl

Cl H H

Cl Cl Cl

Other suitable pyridomorphinans include those possessing an aryl or heteroaryl substituent at the 5 '-position of the pyridine ring of 17-cyclopropylmethyl-4,5 alpha- epoxypyrido[2',3':6,7]morphinan {see, e.g., Ananthan et al. (2003) Bioorg. Med. Chem., 11(18): 4143-4154, and Ananthan et al. (2003) Bioorg. Med. Chem. Letts., 13: 529-532). Such compounds include pyridomorphinans according to Formula I having combinations of R, X, and Y groups as shown in Table 2.

[0046] Table 2. Illustrative combinations of R, X, and Y groups in Formula I.

R X Y

10a H H F

10b H H Br

10c H H CH₃

1Od H H CH₃O

1Oe H H CF₃

1Of H H NO2

1Og H H C₆H₅

1Oh H Cl H

1Oi H Br H

10j H CF₃ H

10k H C₆H₅ H

101 Cl H H

10m Br H H

1On NO₂ H H

1Oo C₆H₅ H H

1Op H Cl Cl

1Oq Cl H Cl

1Or H CH=CH-CH=CH

10s CH=CH-CH=CH H

[0047] Such compounds also include pyridomorphinans according to Formula II having R¹ groups as show in Table 3.

048] Table 3. Illustrative R¹ groups in Formula II. o W

lie

6b CN

6c CO₂-C₂H₅

6d NO₂

6e NH₂

6f NHCH₂C₆H₅

6g CH₂NHC₆H₅

6h 1-pyrrolyl

6i NH(C=NH)NH₂

3 H

[0049] Additional suitable agents include naltrindole derivatives according to

Forumula III:

where R is CPM, allyl, or Me, and X is H or OH. Certain preferred embodiments are illustrated by combinations of R and X as shown in Table 4.

[0050] Table 4. Illustrative combinations of R and X in formula III.

No R X

3 CPM OH

4 Allyl OH

5 Me OH

6 Me H

[0051] Other suitable agents include compounds according to Formula IV:

where X is H or OH, R³ is CPM (cyclopropylmethyl), ally, or Me, R¹ is H, Ph, 4ClPh and the like, and R² is H or Me. Certain preferred embodiments are listed in Table 5 {see also, Ananthan et al (2004) /. Med. Chem., 47(6): 1400-1412).

[0052] Table 5. Illustrative combinations of R¹, R², R³, and X in Formula IV.

No R¹ R² X

3 H H CPM OH

4 Ph H CPM OH

5 4ClPh H CPM OH

H, Ph, 4ClPh H, Me CPM, allyl, Me H, OH

7a 4 chlorophenyl H allyl OH

7b H H Me OH

7c phenyl H Me OH

7d 4 chlorophenyl H Me OH

7e 4 chlorophenyl H Me OH

Ii H H Me H

7g phenyl H Me H

7h 4 chlorophenyl H Me H

7i 4 bromophenyl H Me H

Ti 3 ,4-dichlorophenyl H Me H

7k 2,4-dichlorophenyl H Me H

71 4-chloroρhenyl H CPM H

7m H Me Me OH

7n phenyl Me Me OH

7o 4-chlorophenyl Me Me OH

7p 4-bromophenyl Me Me OH

7q 4-chlorophenyl Me CPM H

2a H H CPM OH

2b phenyl H CPM OH

2c 4-chlorophenyl H CPM OH [0053] Still other suitable agents include but are not limited to, analogues of the delta opioid receptor antagonist naltrindole possessing a phenyl, phenoxy, or benzyloxy group at the 4'-, 5'-, &-, or 7'-positions and a 2-(2-pyridinyl)ethenyl group at the 5'-position on the indolic benzene ring {see, e.g., compounds 4-16 in Ananthan et al. (1998) J. Med. Chem., 41(15): 2872-2881), various pyrido- and pyrimidomorphinans that can be synthesized from naltrexone {see, e.g., compounds a-h and 7a-g in Ananthan et al. (1999) J Med Chem., 42(18): 3527-3538, which is incorporated herein by reference for such compounds).

[0054] In certain preferred embodiments, the inverse agonist or antagonist is SoRI

9409 (5'-(4-chlorophenyl)-17-(cyclopropylmethyl)-6,7-didehydro-3,14-dihydroxy-4,5alpha- epoxypyrido-[2',3':6,7]morphinan), shown in Figure 1, a naltrexone-derived non-peptide ligand and/or SoRI 20411, and/or the Eli Lilly compound LY255525, and/or its related analogs, 6 beta naltrexol, and/or naltrexamide.

[0055] In certain embodiments ,the agents include compounds shown in U.S.

Patents 4,816,586, 5,223,507, 5,811,400, 6,593,348, 6,552,032, 6,291,470, 5,298,622, 6,531,481, 6,887,876, 6,696,457, and the like, which are incorporated herein by reference in their entirety and particularly for the structures disclosed therein.

[0056] It is also noted that delta opioid receptor antagonists are disclosed in U.S.

Patents 5,578,725; 5,464,841; 5,352,680; 5,332,818; and 4,816,586, which are incorporated herein by reference in their entirety and particularly for the structures disclosed therein.

II. Identification of additional agents.

[0057] As indicated above, in certain embodiments, the methods of this invention utilize agents that are agonists at mu and delta opioid receptors when they are expressed alone or when the mu and delta opioid receptors are expressed together in cell lines; and/or that are agonists at the mu and/or delta opioid receptor(s) only when the mu and delta opioid receptors are expressed together but not when they are expressed alone. In certain embodiments the agent(s) are also inverse agonists and/or antagonists at delta opioid receptors when these receptors are expressed alone.

[0058] Various test materials {e.g., drugs) can readily be screened for the agonist activity at mu and/or delta opioid receptors and/or for inverse agonist activity at the delta opioid receptors when the receptors are expressed together or alone. Means of screening for agonistic activity or inverse agonistic activity and mu and/or delta opioid receptors are well known to those of skill in the art.

[0059] Typically such screening is performed by providing cells expressing one or both (mu and/or delta) opioid receptors, contacting the cells with the test agent(s) in the absence and/or presence of a ligand for the receptor(s) {e.g.₄ a synthetic or endogenous ligand) and determining if the test agent(s) show agonistic or inverse agonistic activity, e.g., by measuring activation and/or inhibition of endogenous (constitutive) activity of the receptor(s). In certain embodiments the cells are transfected with one or more nucleic acid constructs that express the desired receptors so that the cell expresses or overexpresses the heterologous mu and/or delta opioid receptor.

[0060] Methods of assaying for activity of opioid receptors and/or other G-protein- coupled receptors (GPCRs) are well known to those of skill in the art. Typical assays measure phosphorylation of the receptor and/or other proteins in the pathway, and/or activation of G protein-coupled receptor kinases (GRK), and/or levels of second messenger(s) (e.g., cAMP). Such assays are well known and kits for performing such assays are commercially available (see, e.g., cAMP assay kit available from NEN Life Science Products Boston, Mass.). It is noted for example, that cAMP assays are described in U.S. patent 6,007,986, while receptor phosphorylation assays are described in U.S. Patent 6,270,979. Various in vivo assays for G-protein-coupled receptor activity are also described in U.S. Patent Publication 2004/0049800.

[0061] It is noted that the assays describe above are intended to be illustrative and not limiting. Using the teaching provided herein, other suitable assays will be routinely performed by one of ordinary skill in the art.

IH. Pharmacological formulations. [0062] In order to carry out the methods of the invention, one or more active agents

(e.g., delta opioid receptor antagonists) of this invention are administered, e.g., to an individual engaged in chronic consumption of a substance of abuse and/or to an individual in withdrawal from chronic consumption of a substance of abuse, and/or to an individual that has ceased or substantially ceased chronic consumption of a substance of abuse. Without being bound to a particular theory, it is believed that the agent or combination of agents described herein will reduce self administration of the substance of abuse and/or craving for such substance, and/or associated anxiety, and/or reinstatement of seeking behavior.

[0063] The active agent(s) can be administered in the "native" form or, if desired, in the form of salts, esters, amides, prodrugs, derivatives, and the like, provided the salt, ester, amide, prodrug or derivative is suitable pharmacologically, i.e., effective in the present method. Salts, esters, amides, prodrugs and other derivatives of the active agents can be prepared using standard procedures known to those skilled in the art of synthetic organic chemistry and described, for example, by March (1992) Advanced Organic Chemistry; Reactions, Mechanisms and Structure, 4th Ed. N. Y. Wiley-Interscience.

[0064] Pharmaceutically acceptable salts of the compounds of the present invention include those derived from pharmaceutically acceptable, inorganic and organic acids and bases. Examples of suitable acids include hydrochloric, hydrobromic, sulfuric, nitric, perchloric, fumaric, maleic, phosphoric, glycolic, lactic, salicyclic, succinic, toluene-p- sulfonic, tartaric, acetic, citric, methanesulfonic, formic, benzoic, malonic, naphthalene-2- sulfonic, trifluoroacetic and benzenesulfonic acids. Salts derived from appropriate bases include, but are not limited to alkali such as sodium and ammonium.

[0065] For example, acid addition salts are prepared from the free base using conventional methodology, that typically involves reaction with a suitable acid. Generally, the base form of the drug is dissolved in a polar organic solvent such as methanol or ethanol and the acid is added thereto. The resulting salt either precipitates or can be brought out of solution by addition of a less polar solvent. Suitable acids for preparing acid addition salts include both organic acids, e.g., acetic acid, propionic acid, glycolic acid, pyruvic acid, oxalic acid, malic acid, malonic acid, succinic acid, maleic acid, fumaric acid, tartaric acid, citric acid, benzoic acid, cinnamic acid, mandelic acid, methanesulfonic acid, ethanesulfonic acid, p-toluenesulfonic acid, salicylic acid, and the like, as well as inorganic acids, e.g., hydrochloric acid, hydrobromic acid, sulfuric acid, nitric acid, phosphoric acid, and the like. An acid addition salt may be reconverted to the free base by treatment with a suitable base. Particularly preferred acid addition salts of the active agents herein are halide salts, such as may be prepared using hydrochloric or hydrobromic acids. Conversely, preparation of basic salts of the active agents of this invention are prepared in a similar manner using a pharmaceutically acceptable base such as sodium hydroxide, potassium hydroxide, ammonium hydroxide, calcium hydroxide, trimethylamine, or the like. Particularly preferred basic salts include alkali metal salts, e.g., the sodium salt, and copper salts.

[0066] Preparation of esters typically involves functionalization of hydroxyl and/or carboxyl groups and/or other reactive groups which may be present within the molecular structure of the drug. The esters are typically acyl-substituted derivatives of free alcohol groups, i.e. , moieties that are derived from carboxylic acids of the formula RCOOH where R is alky, and preferably is lower alkyl. Esters can be reconverted to the free acids, if desired, by using conventional hydrogenolysis or hydrolysis procedures. [0067] Amides and prodrugs can also be prepared using techniques known to those skilled in the art or described in the pertinent literature. For example, amides may be prepared from esters, using suitable amine reactants, or they may be prepared from an anhydride or an acid chloride by reaction with ammonia or a lower alkyl amine. Prodrugs are typically prepared by covalent attachment of a moiety that results in a compound that is therapeutically inactive until modified by an individual's metabolic system.

[0068] The active agents identified herein are useful for parenteral, topical, oral, nasal (or otherwise inhaled), rectal, or local administration, such as by aerosol or transdermally, for prophylactic and/or therapeutic treatment of one or more of the pathologies/indications described herein (e.g., to mitigate one or more behaviors associated with substance abuse). The pharmaceutical compositions can be administered in a variety of unit dosage forms depending upon the method of administration. Suitable unit dosage forms, include, but are not limited to powders, tablets, pills, capsules, lozenges, suppositories, patches, nasal sprays, injectables, implantable sustained-release formulations, lipid complexes, etc. [0069] The active agents of this invention are typically combined with a pharmaceutically acceptable carrier (excipient) to form a pharmacological composition. Pharmaceutically acceptable carriers can contain one or more physiologically acceptable compound(s) that act, for example, to stabilize the composition or to increase or decrease the absorption of the active agent(s). Physiologically acceptable compounds can include, for example, carbohydrates, such as glucose, sucrose, or dextrans, antioxidants, such as ascorbic acid or glutathione, chelating agents, low molecular weight proteins, protection and uptake enhancers such as lipids, compositions that reduce the clearance or hydrolysis of the active agents, or excipients or other stabilizers and/or buffers.

[0070] Other physiologically acceptable compounds include wetting agents, emulsifying agents, dispersing agents or preservatives that are particularly useful for preventing the growth or action of microorganisms. Various preservatives are well known and include, for example, phenol and ascorbic acid. One skilled in the art would appreciate that the choice of pharmaceutically acceptable carrier(s), including a physiologically acceptable compound depends, for example, on the route of administration of the active agent(s) and on the particular physio-chemical characteristics of the active agent(s). [0071] The excipients are preferably sterile and generally free of undesirable matter.

These compositions may be sterilized by conventional, well-known sterilization techniques.

[0072] In therapeutic applications, the compositions of this invention are administered to a patient engaged in chronic consumption of a substance of abuse (e.g., alcohol), and/or to a patient suffering from withdrawal from chronic consumption of a substance of abuse, and/or to a patient engaged in maintaining reduced consumption of the substance and/or abstinence in an amount sufficient to prevent and/or cure and/or or at least partially prevent or arrest one or more components of behavior associated with chronic consumption of a substance of abuse or the cessation thereof. An amount adequate to accomplish this is defined as a "therapeutically effective dose." Amounts effective for this use will depend upon the severity of the disease and the general state of the patient's health. Single or multiple administrations of the compositions may be administered depending on the dosage and frequency as required and tolerated by the patient. In any event, the composition should provide a sufficient quantity of the active agents of the formulations of this invention to effectively treat the condition. [0073] The concentration of active agent(s) can vary widely, and will be selected primarily based on fluid volumes, viscosities, body weight and the like in accordance with the particular mode of administration selected and the patient's needs. Concentrations, however, will typically be selected to provide dosages ranging from about 0.1 or 1 mg/kg/day to about 50 mg/kg/day and sometimes higher. Typical dosages range from about 3 mg/kg/day to about 3.5 mg/kg/day, preferably from about 3.5 mg/kg/day to about 7.2 mg/kg/day, more preferably from about 7.2 mg/kg/day to about 11.0 mg/kg/day, and most preferably from about 11.0 mg/kg/day to about 15.0 mg/kg/day. In certain preferred embodiments, dosages range from about 10 mg/kg/day to about 50 mg/kg/day. In certain embodiments, dosages range from about 20 mg to about 50 mg given orally twice daily. It will be appreciated that such dosages may be varied to optimize a therapeutic regimen in a particular subject or group of subjects.

[0074] In certain preferred embodiments, the active agents of this invention are administered orally (e.g., via a tablet) or as an injectable in accordance with standard methods well known to those of skill in the art. In other preferred embodiments, the agents may also be delivered through the skin using conventional transdermal drug delivery systems, i.e., transdermal "patches" wherein the active agent(s) are typically contained within a laminated structure that serves as a drug delivery device to be affixed to the skin. In such a structure, the drug composition is typically contained in a layer, or "reservoir," underlying an upper backing layer. It will be appreciated that the term "reservoir" in this context refers to a quantity of "active ingredient(s)" that is ultimately available for delivery to the surface of the skin. Thus, for example, the "reservoir" may include the active ingredient(s) in an adhesive on a backing layer of the patch, or in any of a variety of different matrix formulations known to those of skill in the art. The patch may contain a single reservoir, or it may contain multiple reservoirs.

[0075] In one embodiment, the reservoir comprises a polymeric matrix of a pharmaceutically acceptable contact adhesive material that serves to affix the system to the skin during drug delivery. Examples of suitable skin contact adhesive materials include, but are not limited to, polyethylenes, polysiloxanes, polyisobutylenes, polyacrylates, polyurethanes, and the like. Alternatively, the drug-containing reservoir and skin contact adhesive are present as separate and distinct layers, with the adhesive underlying the reservoir which, in this case, may be either a polymeric matrix as described above, or it may be a liquid or hydrogel reservoir, or may take some other form. The backing layer in these laminates, which serves as the upper surface of the device, preferably functions as a primary structural element of the "patch" and provides the device with much of its flexibility. The material selected for the backing layer is preferably substantially impermeable to the active agent(s) and any other materials that are present. [0076] Other preferred formulations for topical delivery include, but are not limited to, ointments and creams. Ointments are semisolid preparations which are typically based on petrolatum or other petroleum derivatives. Creams containing the selected active agent, are typically viscous liquid or semisolid emulsions, often either oil-in-water or water-in-oil. Cream bases are typically water-washable, and contain an oil phase, an emulsifier and an aqueous phase. The oil phase, also sometimes called the "internal" phase, is generally comprised of petrolatum and a fatty alcohol such as cetyl or stearyl alcohol; the aqueous phase usually, although not necessarily, exceeds the oil phase in volume, and generally contains a humectant. The emulsifier in a cream formulation is generally a nonionic, anionic, cationic or amphoteric surfactant. The specific ointment or cream base to be used, as will be appreciated by those skilled in the art, is one that will provide for optimum drug delivery. As with other carriers or vehicles, an ointment base should be inert, stable, nonirritating and nonsensitizing.

[0077] In various embodiments the active agents described herein can can be administered orally in which case delivery can be enhanced by the use of protective excipients. This is typically accomplished either by complexing the active agent(s) with a composition to render them resistant to acidic and enzymatic hydrolysis or by packaging the agents in an appropriately resistant carrier, e.g., a liposome. Means of protecting agents for oral delivery are well known in the art (see, e.g., U.S. Patent 5,391,377).

[0078] Elevated serum half -life can be maintained by the use of sustained-release "packaging" systems. Such sustained release systems are well known to those of skill in the art (see, e.g., Tracy (1998) Biotechnol. Prog. 14: 108; Johnson et al (1996), Nature Med. 2: 795; Herbert et al. (1998), Pharmaceut. Res. 15: 357, and the like).

[0079] In another embodiment, one or more components of the solution can be provided as a "concentrate", e.g., in a storage container (e.g., in a premeasured volume) ready for dilution, or in a soluble capsule ready for addition to a volume of water.

[0080] In certain embodiments, one or more active agents described herein are administered alone or in combination with other therapeutics in implantable (e.g., subcutaneous) matrices.

[0081] A major problem with standard drug dosing is that typical delivery of drugs results in a quick burst of medication at the time of dosing, followed by a rapid loss of the drag from the body. Most of the side effects of a drag occur during the burst phase of its release into the bloodstream. Secondly, the time the drug is in the bloodstream at therapeutic levels is very short, most is used and cleared during the short burst.

[0082] Drugs (e.g., the active agent(s) described herein) imbedded in various matrix materials for sustained release provides some solution to these problems. Drugs embedded, for example, in polymer beads or in polymer wafers have several advantages. First, most systems allow slow release of the drug, thus creating a continuous dosing of the body with small levels of drug. This typically prevents side effects associated with high burst levels of normal injected or pill based drags. Secondly, since these polymers can be made to release over hours to months, the therapeutic span of the drag is markedly increased. Often, by mixing different ratios of the same polymer components, polymers of different degradation rates can be made, allowing remarkable flexibility depending on the agent being used. A long rate of drug release is beneficial for people who might have trouble staying on regular dosage, such as the elderly, but is also an ease of use improvement that everyone can appreciate. Most polymers can be made to degrade and be cleared by the body over time, so they will not remain in the body after the therapeutic interval.

[0083] Another advantage of polymer based drug delivery is that the polymers often can stabilize or solubilize proteins, peptides, and other large molecules that would otherwise be unusable as medications. Finally, many drag/polymer mixes can be placed directly in the disease area, allowing specific targeting of the medication where it is needed without losing drag to the "first pass" effect. This is certainly effective for treating the brain, which is often deprived of medicines that can't penetrate the blood/brain barrier.

[0084] A number of implantable matrix (sustained release) systems are know to those of skill and can readily be adapted for use with one or more of the active agents described herein. Suitable sustained release systems include, but are not limited to Re- Gel®, SQ2Gel®, and Oligosphere® by MacroMed, ProLease® and Medisorb® by

Alkermes, Paclimer® and Gliadel® Wafer by Guilford pharmaceuticals, the Duros implant by Alza, acoustic biSpheres by Point Biomedical, the Melsite capsule by Scintipharma, Inc., and the like. [0085] The foregoing formulations and administration methods are intended to be illustrative and not limiting. It will be appreciated that, using the teaching provided herein, other suitable formulations and modes of administration can be readily devised.

IV. Combined Formulations.

[0086] In certain embodiments, this invention discloses the administration of delta opioid receptor antagonists (more preferably a preferential- and still more preferably a specific delta opioid receptor antagonist) in conjunction with one or more opiate analgesics to delay the development of tolerance to the antinociceptive effect of the opiate analgesic(s). In certain embodiments the opiate analgesic(s) are and delta opioid receptor antagonist(s) are provided as combined formulation. In certain embodiments the receptor antagonist(s) and analgesic(s) can be combined at the time of administration or they can be provided as a single formulation.

[0087] Suitable delta opioid receptor antagonists include, but are not limted to those described above. Suitable opiate analgesics include, but are not limited to natural opium alkaloids {e.g., morphine, opium, hydromorphone, nicomorphine, oxycodone, dihydrocodeine, diamorphine, papaveretum, codeine, and the like), phenylpiperidine derivatives {e.g., ketobemidone, pethidine, fentanyl, and the like), diphenylpropylamine derivatives {e.g., dextromor amide, piritramide, dextropropoxyphene, bezitramide, dextropropoxyphene, and the like), benzomorphan derivatives {e.g., pentazocine, phenazocine, and the like), oripvaine derivatives {e.g., buprenorphine, and the like), morphinan derivatives {e.g., butorphanol, nalbufme, and the like), and other opioids {e.g., tilidine, tramadol, dezocine, and the like).

V. Kits.

[0088] This invention also contemplates kits for practice of the methods of this invention. Such kits typically include a container containing one or more active agents as described herein. The kits typically additionally include instructional materials teaching the use of such agent to inhibit one or more components of addictive behavior associated with consumption of a substance of abuse {e.g., to inhibit consumption of alcohol). The instructional materials can teach preferred dosages, modes of administration, counter- indications, and the like. [0089] While the instructional materials typically comprise written or printed materials they are not limited to such. Any medium capable of storing such instructions and communicating them to an end user is contemplated by this invention. Such media include, but are not limited to electronic storage media {e.g., magnetic discs, tapes, cartridges, chips), optical media {e.g., CD ROM), and the like. Such media may include addresses to

EXAMPLES

[0090] The following examples are offered to illustrate, but not to limit the claimed invention.

Example 1 SoRI9409 and SoRI20411 Inhibit Alcohol Consumption.

Methods and Materials

Free Access Two Bottle Choice Ethanol Consumption

[0091] Twelve Long-Evans rats were purchased from Harlan (Indianopolis, IN) and individually housed on a 12:12 lighfcdark cycle (lights on 6AM; lights off 6PM) with ad libitum access to food. Fluids were presented daily in 100-ml graduated glass cylinders with stainless steel drinking spouts inserted through the front of the cage just before the beginning of the dark cycle. Prior to testing, rats were given at least one week to acclimatize to the individual housing conditions and handling. During this period, water was the only fluid available. Rats were then given concurrent access to a solution containing 10% v/v ethanol + 10% v/v sucrose and a separate water bottle. Over the next 12 days, the sucrose concentration was gradually decreased {i.e. 5, 2, and finally 0%). For the remainder of the experiment, the animals had continuous access to 10% v/v ethanol solution and a separate water bottle. Intake was measured twice daily, 16 and 24 hrs. after fresh fluids were placed on the cages. Measurements were taken to the nearest .5 ml. The data was corrected for evaporation and spillage by subtracting the mean fluid loss measured in two drinking tubes placed on an empty cage. Position of the tubes (left/right) was alternated to control for side preferences. Drug administrations began after the rats had reached stable drinking levels of the 10% v/v ethanol solution (2-3 weeks following removal of the sucrose). In a within subject design, each rat was tested at each dose of SoRI 9409 and SoRI20411 were delivered intraperitoneally (ip) with a minimum of four days between drug administrations to allow for the drugs to washout. Animal weights were measured daily in order to calculate the gram per kilogram intake. Ethanol preference (%) was calculated as the mis. of ethanol consumed divided by the total fluid consumption (mis. of EtOH + mis. of water).

Drugs [0092] SoRI9409 and SoRI20411 were supplied by the Southern Research Institute.

The drugs were initially dissolved DMSO and then further diluted with distilled water (injection volume of lmL/kg for all doses). 5-10 μL of glacial acetic acid was added to keep the drugs in solution.

Receptor-mediated F³⁵SIGTP YS binding. [0093] Membranes were prepared HEK293 cells containing mu opioid receptor

(MOPr) or delta opioid receptor (DOPr) or MOPr and DOPr together. 5-30 μg of membranes were incubated in assay buffer (20 mM HEPES, 100 mM NaCl, 5 mM MgC12, 10μg/ml saponin, 5-20 μM GDP, pH 7.5) in a 96-well white Nunc plate at RT. The assay was started by adding 0.5nM [³⁵S]GTPyS and drugs were incubated for 45 minutes on RT in the presence of 0.5 mg/μg protein of wheat germ agglutinin-coated SPA beads

(Amersham). The assays were terminated by centrifugation of the plates for 5 min at 1500 rpm and radioactivity was measured in a Packard Top counter. All data were normalized by substracting non-specific binding determined in the presence of 10 μM of cold GTPγS.

Cell Culture and Immunocytochemistry. [0094] Human Embryonic Kidney (HEK) 293 cells (American Type Culture

Collection) were grown in DMEM (Gibco BRL) supplemented with 10% Fetal Bovine Serum (Hyclone). N-terminal FLAG- and/or HA-tagged MOPr or DOPr constructs were stably expressed in HEK293 cells. For generation of clonal stable cell lines, single colonies were chosen and propagated in the presence of selection-containing media. The antibody- feeding immunocytochemistry were essentially as described⁵ except DAMGO (DAMGO, 5 μM, 30 min), SORI9409 (5 μM), or SoRI 20411 (5 μM) were used. Briefly, cells stably expressing FLAG-tagged MOPr or DOPr were grown on coverslips to 50% confluency. Live cells were fed either Ml or HA antibody (Sigma) directed against the FLAG tag (1 : 1000, 30 minutes or HA tag (1 : 1000, 30 mins). Cells were then treated with drug (5 μM DA, 30 minutes) or left untreated. Untreated cells were then fixed with 4% formaldehyde in PBS. Cells were then either fixed and the cells permeabilized in blotto with 0.1% Triton X- 100 and stained with fluorescently conjugated secondary antibody (1:500, Molecular Probes).

Analysis of receptor recruitment using flow cytometry.

Flow Cytometer.

[0095] An Influx flow cytometer (Cytopeia, Inc.) equipped with a 488nm Sapphire and 633nM Radius lasers (Coherent) was used for all experiments.

Antibody [0096] Ml anti-FLAG antibody (Sigma) and Goat anti-mouse IgG Fab' fragments

(Sigma) were labeled with CypHer5e dye (Amersham) according to the manufacturers instructions. This fluorophore is excited with the 633nM and emits at 664nm when exposed to pH of less than ~6.5 normally found in the endoctyic compartments. At pH of greater than 7.4, the dye is essentially non-fluorescent. Ml antibody was labelled with a 6:1 or a 4:1 molar Fab':Ml ratio with CypHer5e-conjuated Goat anti-mouse IgG Fab' fragments for 15 minutes at room temperature, and the unbound Fab' fragments were blocked with the addition of non-specific mouse IgG (Sigma).

Example 2

Investigation into the development of tolerance to the antinociceptive effects of morphine when co-administered with SoRI 9409 in rats

[0097] Tolerance to the pain-relieving effects of opioids, such as morphine, is a problem encountered in the clinical setting in patients receiving these drugs for the relief of chronic pain. Recent successful strategies utilized to reduce or prevent morphine tolerance development have included co-administration of low doses of opioid antagonists, such as the non-selective opioid antagonist, naltrexone, with morphine. This opioid combination has reportedly provided greater levels of pain relief and reduced morphine tolerance in chronic pain patients (Gan et al. (1997) Anesthesiology, 87: 1075-1081). Similarly, the development of tolerance to the antinociceptive effects is morphine has been reported to be delayed in rodents co-administered very low doses of naltrexone (Crain and Shen (1995) Proc. Natl. Acad. ScL, USA, 92(7): 10540-10544; Shen and Crain (1997) Brain Res. 757: 176-190; Powell et al. (2002) /. Pharmacol. Exp. Ther., 300: 588-596). In vitro studies suggest that ultra-low doses of naltrexone may selectively block sustained activation of excitatory opioid receptor functions such as those postulated to mediate tolerance and dependence, while minimizing antagonist activity at inhibitory opioid receptors that mediate antinociception (Crain and Shen (1995) Proc. Natl. Acad. ScL, USA, 92(7): 10540-10544; Shen and Crain (1997) Brain Res. 757: 176-190; Wang et al. (2005) Neuroscience, 135: 247-261). Previous studies in mice have indicated that the δ-opioid receptor may be involved in the development of tolerance to the effects of μ-opioid agonists, such as morphine (Abdelhamid et al. (1991) J. Pharmacol. Exp. Ther., 258: 299-303; Zhu et al. (1999) Neuron, 24: 243-252). The administration of selective δ-opioid receptor antagonists was reported to prevent the development of antinociceptive tolerance to morphine in mice (Abdelhamid et al. (1991) /. Pharmacol. Exp. Ther., 258: 299-303). Follow-up studies showed that this effect was mediated via δ₂-opioid receptors, rather than δi-receptors

(Miyamoto et al. (1993) Pharmacol. Exp. Ther., 264: 1141-1145; Miyamoto et al. (1994) Pharmacol. Exp. Ther., 270: 1069-1075). Furthermore, mice with a genetic deletion of the cloned δ-opioid receptor were reported not to develop antinociceptive tolerance to morphine, in contrast to wild-type mice (Zhu et al. (1999) Neuron, 24: 243-252). [0098] This example describes an investigation as to whether the development of antinociceptive tolerance to morphine is altered when co-administered with the naltrexone- derived compound, SoRI 9409 (5'-(4-Chlorophenyl)-17-(cycloρropylmethyl)-6,7- didehydro-3,14-dihydroxy-4,5alpha-epoxypyrido-[2',3':6,7]morphinan), compared to that with naltrexone. [0099] Binding studies have reported SoRI 9409 to be a relatively potent δ-opioid antagonist, also with moderate μ- and κ-antagonist activity (Ananthan et al. (1995) J. Med. Chem., 42: 3527-3538; Zhu et al. (1999) Neuron, 24: 243-252). Although SoRI 9409 was previously reported to produce antinociception via an apparent μ-opioid agonist action, limited tail-flick antinociception was observed, with mice displaying only up to -40% MPE following i.c.v. administration of doses up to 100 nmol and no antinociception following high systemic dosing (30-60 mg/kg i.p.) (Ananthan et al (1995) J. Med. Chem., 42: 3527- 3538; Wells et al. (2001) J. Pharmacol. Exp. Ther., 297: 597-605).

Methods

Animals

[0100] Adult Male Long-Evans rats (249 ±4 g, mean ± SEM; mean ± SEM) housed in a temperature controlled environment (22 ± 2⁰C) with a 12 h/12 h light/dark cycle. Food and water were available ad libitum. Protocols related to the experiment were approved by the Institutional Animal Care and Use Committee and are in accordance with the National Institute on Drug Abuse, National Institutes of Health, and the Guide for the Care and Use of Laboratory Animals.

Antinociceptive testing

[0101] The tail flick latency test was used to quantify antinociception (D'Amour and

Smith (1941) J. Pharmacol. Exp. Ther., 72: 74-79), with the thermal stimulus being applied to the lower third of the ventral surface of the rat's tail. The mean initial pre-dosing baseline tail flick latency was 2.45 s (range, 1 to 3 s). Antinociceptive testing was performed pre-dosing and then at 30 min post-dosing at each time-point until the rats were completely tolerant to the antinociceptive effects of the administered opioid as shown by a return to baseline levels of antinociception. A maximum of 9 s was used to minimize tissue damage to the rat's tails. The tail flick latency values were converted to a percentage of the maximum possible effect (% MPE) (Brady and Holtzmann (1982) J. Pharmacol. Exp. Ther., 222: 190-197):

%MPE = post-drug latency - predrug latency x 100% maximum latency (9 s) - predrug latency

Opioid Dosing

[0102] Groups of rats were administered twice daily intraperitoneal (i.p) doses of morphine (7.5 mg/kg) with either naltrexone (10 ng/kg; n=4), SoRI 9409 (10 ng/kg; n=4) or saline (n=3). Groups of rats also received either naltrexone (10 ng/kg i.p; n=l) or SoRI 9409 (10 ng/kg i.p; n=l) with saline. Results

[0103] Rats administered twice daily doses of morphine (7.5 mg/kg; with saline), were shown to be tolerant to the antinociceptive effects of morphine after 48-54 h (Figure 5). In comparison, a delayed tolerance to the antinociceptive effects of morphine in rats coadministered morphine with either naltrexone or SoRI 9409 (10 ng/kg) was observed (72-84 h). Although rats co-administered SoRI 9409 with morphine displayed slightly higher levels of antinociception than rats administered morphine with naltrexone at the 24 to 48 h post-dosing time-points, these were not significant different (p > 0.05). Rats administered either naltrexone or SoRI 9409 alone produced insignificant levels of antinociception, compared to pre-dosing baseline latencies (p > 0.05).

Conclusion

[0104] Co-administration of SoRI 9409 with morphine appears to delay the development of tolerance to the antinociceptive effects of morphine in rats in a similar fashion to that observed with morphine and naltrexone combined dosing. This indicates that recruitment of delta opioid receptors to the cell surface may be associated with the delay in the development of morphine tolerance previously observed for naltrexone.

Example 3

Investigating the effects of the δ-opioid receptor antagonist, SoRI 9409, in a model of alcohol consumption and relapse, in rats.

Introduction [0105] There are presently only two effective commercially available treatments alcoholism, Naltrexone and Acamprosate. Naltrexone is a non-specific opioid receptor antagonist and acamprosate' s mechanism of action is not entirely understood. In both cases there can be severe adverse side effects and patient compliance is therefore low. For these reasons there is a need for development of better medications to treat and prevent alcohol consumption, abuse and relapse. The development of effective treatments for alcoholism is, however, hindered by a number of factors. Most notable is the lack of a good model for validating lead compounds, a fact compounded by the length of time required to perform the currently employed models. Operant self administration of the standard 10% ethanol solution, for example, requires a sucrose fading technique and can take up to 2 months to establish stable base-line consumption. Richter (1953) Quart. J. Studies on Alcohol., 14(4): 525-539, first demonstrated that rodents will voraciously self administer beer though he assumed this was more for the taste than the alcohol. Gallate and McGregor (1999) Psychopharmacology, 142: 302-308, observed that rats will drink significantly more beer than unflavoured ethanol solutions with the same ethanol content. They presented an elegant series of studies to show that ritanserin, naloxone and SR 141716, were capable of selectively reducing beer consumption in rats in a 30minute limited access paradigm; suggesting consumption was specific to the alcohol content (Id.).

[0106] We have evaluated this model and developed the use of beer and near beer as reinforcers in the operant self administration paradigm as a high content model for screening potential lead compounds.

[0107] Although Naltrexone has been shown to be effective in treating alcoholism it has a range of adverse side effects and subsequent poor compliance levels. The adverse effects may be attributed to the non-specific nature of the compound and so a number of derivatives with increased specificity for individual opioid receptor subtypes have been developed, although without specific testing, their efficacy in is unpredictable.

[0108] One such derivative is SoRI 9409, (5'-(4-Chloroρhenyl)-17-

(cyclopropylmethyl)-6,7-didehydro-3,14-dihydroxy-4,5alpha-epoxypyrido- [2',3':6,7]morphinan). Binding studies have reported SoRI 9409 to be a relatively potent δ- opioid antagonist, with moderate μ- and κ-antagonist activity (Ananthan et al. (1999) J. Med. Chem., 42: 3527-3538; Xu et al. (2001) Brain Res. Bul.,155: 507-511).

[0109] The present study pertains to the investigation of the effects of SoRI 9409 in a beer/near beer operant self administration model and to the determination of whether or not δ-opioid receptor antagonism produces a similar or more specific treatment profile compared to Naltrexone. Methods

Animals

[0110] Adult male Long Evans rats (180-20Og at start of experiment) were individually housed in a temperature controlled environment (22±2°C) on a 12hr/12hr light:dark cycle with lights on at 7am. Food and water were available ad libitum in the home cage except where stated below for initiation of behavior acquisition. AU protocols involved were previously approved by the Institutional Animal Care and Use Committee and are in accordance with the National Institute on Drug Abuse, National Institutes of Health, and the Guide for the Care and Use of Laboratory Animals.

Operant Self Administration [0111] Rats were randomly assigned to one of four groups and pre-exposed to their assigned reinforcer solutions (4.5% beer (v/v), near beer, 5% sucrose (g/v), or 4.5% ethanol (v/v)) in the home cage for 3 days before commencing operant sessions. Operant sessions were conducted in standard operant behavior chambers (Coulbourn Instruments Inc.) that include 2 levers, a liquid delivery system, tone, stimulus lights above each lever and a house light. Sessions were conducted 5 days a week (Mon - Fri) at the same time each day. Rats were trained to respond for a liquid reinforcer by first water depriving them for 22 hours and then placing them in the operant chambers over night for 12-14 hours for up to 2 sessions. The reinforcer solution was available after successful completion of an operant (active lever press) response on a fixed ratio FRl schedule; 1 lever press on the active lever results in the light above the active lever being turned on and a tone sounding for 3 seconds, followed by delivery of 1 reward of 0.1ml reinforcer in the drinking port. After a successful overnight session animals were placed on restricted water for 1 hour per day in the home cage, immediately after completing an operant session, for 2-3 days. Rats were trained to respond for reinforcers without using a sucrose fading technique. Initially rats were placed in the operant chambers for 45 minute sessions on an FRl schedule, over the course of two weeks animals progressed to having Ad Lib water access in the home cage and continued 45 minutes sessions FRl, for a further 3-4 sessions and then on to an FR3 schedule for 30 minute sessions (FR3 requires 3 consecutive presses on the active lever for presentation of cues and reward delivery). AU future sessions were 30 minutes on an FR3 schedule of reinforcement. Animals were trained until they reached a stable baseline of responding on the active lever, which took 5 weeks (25 sessions).

Extinction

[0112] Once rats acquired a stable response baseline they were placed in extinction sessions. During extinction sessions the house light remained on but pressing on either the inactive or previously active lever resulted in no cue presentation or reward delivery.

Animals continued with daily extinction sessions until their response levels had dropped to less than 10% of their previous baseline responding for 2 consecutive days. This typically took 12-15 sessions.

Deprivation [0113] A second group of animals were trained to self administer either beer or near beer as described above. Once they had reached stable baseline responding they were returned to their home cage for 5 weeks - home cage deprivation.

Cue-induced Reinstatement

[0114] Once animals reached extinction criteria they were given a single non- contingent presentation of the previously reward-associated cues (tone and light), in order to initiate a reinstatement response. Home cage deprived animals did not undergo extinction training and so were placed back in the chamber and not given a non-contingent cue presentation but did receive cues after successful active lever presses (FR3).

[0115] After the reinstatement session animals were placed back on normal training sessions with cue presentation and reward delivery on an FR3 schedule. Animals were then tested with compounds on a weekly basis (see Drug section below).

Drugs

[0116] Drugs were tested on a weekly basis with each animal receiving drug and vehicle in a counterbalanced manner each week. Naltrexone HCl was solubilized in 0.9% sterile saline at lmg/ml and administered s.c. at a dose of lmg/kg. SoRI 9409 was solubilised in 2% DMSO acidified water (pH 5.3) at 5mg/ml and administered i.p. at a dose of 5mg/kg. Both drug and vehicle were administered 30min prior to session during which the animals remained in their home cage. Testing days were Wed/Thurs to allow for pre/post treatment data collection on Tue/Fri.

Results

[0117] Rats administered with lmg/kg Naltrexone showed significant reduction in responding for all reinforcers after a period of extinction (Figure 6). In comparison rats administered with 5m/kg SoRI 9409 showed significant reduction of responding only for near beer and 4.5% ethanol. Sucrose responding was unaffected and although beer responding showed a trend towards reduction it was not significant (Figure 7). In contrast to animals going through extinction training animals who were home cage deprived showed a much more significant beer-selective response to both Naltrexone and SoRI 9409 (Figures 8 and 9). This indicates that SORI9409 is more effective for use in alcohol deprivation.

Discussion

[0118] The non-specific effects of Naltrexone, in extinguished animals, suggests the rats are reducing their responding due to adverse effects of the treatment rather than an alcohol specific effect as near beer and sucrose responses were inhibited although to a lesser extent than beer and 4.5% ethanol responses. This is in accordance with previously reported data that Naltrexone reduces self administration of ethanol in rodents. It is noted that, in deprived animals, there is a pronounced selectivity for reducing beer responding over near beer responding. These results indicate that the method of withdrawal plays an important role in the way that animals respond to potential treatments. Secondly it indicates that maybe the δ-opioid receptor is more important in relapse than the reward pathway.

[0119] It is understood that the examples and embodiments described herein are for illustrative purposes only and that various modifications or changes in light thereof will be suggested to persons skilled in the art and are to be included within the spirit and purview of this application and scope of the appended claims. AU publications, patents, and patent applications cited herein are hereby incorporated by reference in their entirety for all purposes.

Claims

CLAIMSWhat is claimed is:

1. A method of delaying the development of tolerance to the antinociceptive effect of an opiate analgesic, said method comprising administering a delta opioid receptor antagonist in conjunction with said opiate analgesic.

2. The method of claim 1, wherein said opiate analgesic is selected from the group consisting of a natural opium alkaloid, a phenylpiperidine derivative, a diphenylpropylamine derivative, a benzomorphan derivative, an oripvaine derivative, and a morphinan derivative.

3. The method of claim 1, wherein said opiate analgesic is selected from the group consisting of morphine, opium, hydromorphone, nicomorphine, oxycodone, dihydrocodeine, diamorphine, papaveretum, codeine, ketobemidone, pethidine, fentanyl, dextromoramide, piritramide, dextropropoxyphene, bezitramide, dextropropoxyphene, pentazocine, phenazocine, buprenorphine, butorphanol, nalbufine, tilidine, tramadol, and dezocine.

4. The method of claim 1, wherein said delta opioid receptor antagonist is selected from the group consisting of 3,4-dimethyl-4-(3-hydroxyphenyl)piperidine derivatives (i.e. LY515300 and its derivatives), H-Tyr-TicPsitC^NJCha-Phe-OH, (TICP(Psi)), 2',6^t-dimethyltyrosine-l,2,3,4-tetrahydroquinoline-3-carboxylate (Dmt-Tic) peptides, ICI-174,864, SoRI 9409, LY255525, 6 beta naltrexol, and naltrexamide.

5. The method of claim 1, wherein the delta opioid receptor antagonist is administered simultaneously with said opiate analgesic.

6. The method of claim 1, wherein the delta opioid receptor antagonist is administered prior to said opiate analgesic.

7. The method of claim 1, wherein the delta opioid receptor antagonist is administered after said opiate analgesic.

8. The method of claim 1, wherein the delta opioid receptor antagonist and said opiate analgesic are provided as a single unit dosage formulation.

9. A pharmaceutical composition comprising a delta opioid receptor antagonist and an opiate analgesic.

10. The composition of claim 9, wherein said opiate analgesic is selected from the group consisting of a natural opium alkaloid, a phenylpiperidine derivative, a diphenylpropylamine derivative, a benzomorphan derivative, an oripvaine derivative, and a morphinan derivative.

11. The composition of claim 9, wherein, wherein said opiate analgesic is selected from the group consisting of morphine, opium, hydromorphone, nicomorphine, oxycodone, dihydrocodeine, diamorphine, papaveretum, codeine, ketobemidone, pethidine, fentanyl, dextromoramide, piritramide, dextropropoxyphene, bezitramide, dextropropoxyphene, pentazocine, phenazocine, buprenorphine, butorphanol, nalbufine, tilidine, tramadol, and dezocine.

12. The composition of claim 9, wherein, wherein said delta opioid receptor antagonist is selected from the group consisting of 3,4~dimethyl-4-(3- hydroxyphenyl)piperidine derivative (i.e. LY515300 and its derivatives), H-Tyr- TicPsi[CH2N]Cha-Phe-OH, (TICP(PSi)), 2',6'-dimethyltyrosine-l,2,3,4- tetrahydroquinoline-3-carboxylate (Dmt-Tic) peptides, ICI-174,864, SoRI 9409, LY255525, 6 beta naltrexol, and naltrexamide.

13. The composition of claim 9, wherein said composition is formulated as a unit dosage formulation.

14. The composition of claim 9, wherein said composition is formulated as a sustained release formulation.

15. The composition of claim 9, wherein said composition is formulated as an injectable.

16. A method of mitigating psychological or physical dependence on a substance of abuse by a mammal, said method comprising administering to said mammal a delta opioid receptor antagonist in an amount sufficient to mitigate psychological or physical dependence on said substance of abuse.

17. The method of claim 16, wherein said substance of abuse is selected from the group consisting of ethanol, an opiate, a cannabinoid, nicotine, and a stimulant.

18. The method of claim 16, wherein said substance of abuse is selected from the group consisting morphine, heroin, marijuana, hashish, cocaine, and amphetamines.

19. The method of claim 16, wherein said substance of abuse is alcohol.

20. The method of claim 16, wherein, wherein said delta opioid receptor antagonist is selected from the group consisting of 3,4~dimethyl-4-(3- hydroxyphenyl)piperidine derivative (i.e. LY515300 and its derivatives), H-Tyr- TicPsi[CH2N]Cha-Phe-OH, (TICP(PSi)), 2',6'-dimethyltyrosine-l,2,3,4- tetrahydroquinoline-3-carboxylate (Dmt-Tic) peptides, ICI-174,864, SoRI 9409, LY255525, 6 beta naltrexol, and naltrexamide.

21. The method of claim 16, wherein said delta opioid receptor antagonist is selected from the group consisting SoRI 9409, LY255525, 6 beta naltrexol, and naltrexamide.

22. The method of claim 16, wherein said mammal is a mammal engaging in chronic consumption of a substance of abuse.

23. The method of claim 16, wherein said mammal is a mammal that has ceased chronic consumption of a substance of abuse.

24. The method of claim 16, wherein said mammal is a mammal undergoing one or more symptoms of withdrawal.

25. The method of claim 16, wherein said mammal is a human.

26. A method of mitigating one or more components of addictive behavior associated with chronic consumption of a substance of abuse, or withdrawal therefrom, or cessation of consumption of a substance of abuse by a mammal, said method comprising: administering to said mammal: a) a first agent that is an agonist at mu and delta opioid receptors when they are expressed alone or when the mu and delta opioid receptors are expressed together in cell lines; and/or b) a second agent that is an agonist only when the mu and delta opioid receptors are expressed together but not when they are expressed alone; wherein said first agent and/or said second agent is administered in an amount sufficient ot mitigate one or more components of addictive behavior.

27. The method of claim 26, wherein said second agent is an inverse agonist at delta opioid receptors when these receptors are expressed alone or together.

28. The method of claim 26, wherein said first agent is selected from the group consisting of SNC 80 [(+)-4-[(alphaR)-alpha-((2S,5R)-4-Allyl-2,5-dimethyl-l- piperazinyl)-3-methoxybenzyl]-N,N-diethylbenzamide], TIPP, Dmt-Tic-OH, N,N(CH3)2- Dmt-Tic-NH₂, Tan67, [D-Pen(2,5)]-enkephalin, DPDPE, H-Try-d-Ala-Phe-Glu-Val-Gly- NH₂, Deltorphin II, BUBU, deltorphin I, [D-Met²]-deltorphin, and SoRI 20411.

29. The method of claim 26, wherein said second agent is selected from the group consisting of 3,4-dimethyl-4-(3-hydroxyphenyl)piperidines derivatives {i.e. LY515300 and its derivatives), H-Tyr-TicPsi[CH2N]Cha-Phe-OH, (TΙCP(Psi)), 2',6'- dimethyltyrosine-l,2,3,4-tetrahydroquinoline-3-carboxylate (Dmt-Tic) peptides, ICI- 174,864, and SoRI 9409.

30. The method of claim 26, wherein said first and/or said second agent is selected from the group consisting of SoRI 9409, SoRI 20411, and SoRI 2404.

31. The method of claim 26, comprising administering said first agent in conjunction with said second agent.

32. The method of claim 26, wherein said first agent or said second agent is selected from the agents of any one of Tables 1 through 5.

33. The method of claim 26, wherein said first agent and/or said second agent is administered in conjunction with a delta opioid receptor antagonist.

34. The method of claim 28, wherein said first agent and/or said second agent is formulated with a pharmacologically acceptable excipient.

35. The agent of claim 34, wherein said first agent and/or said second agent is in a unit dosage formulation.

36. The method of claim 26, wherein said substance of abuse is selected from the group consisting of ethanol, an opiate, a cannabinoid, nicotine, and a stimulant.

37. The method of claim 26, wherein said substance of abuse is selected from the group consisting morphine, heroin, marijuana, hashish, cocaine, and amphetamines.

38. The method of claim 26, wherein said substance of abuse is ethanol.

39. The method of claim 26, wherein said component of addictive behavior is chronic self- administration of said substance of abuse.

40. The method of claim 26, wherein said component of addictive behavior is craving for said substance of abuse.

41. The method of claim 26, wherein said component of addictive behavior is reinstatement of seeking behavior for said substance of abuse.

42. The method of claim 26, wherein said mammal is a mammal engaging in chronic consumption of a substance of abuse.

43. The method of claim 26, wherein said mammal is a mammal that has ceased chronic consumption of a substance of abuse.

44. The method of claim 26, wherein said mammal is a mammal undergoing one or more symptoms of withdrawal.

45. The method of claim 26, wherein said mammal is a human.

46. The method of claims 26 or 45, wherein inhibiting comprises reducing self-administration of alcohol.

47. The method of claim 46, wherein said first agent comprises SoRI 20144 or a derivative thereof.

48. The method of claim 46, wherein said first agent comprises SoRI 20144.

49. The method of claim 46, wherein said second agent comprises SoRI 9409 or a derivative thereof.

50. The method of claim 46, wherein said second agent comprises SoRI 9409.

51. A method of inducing weight loss in a mammal, said method comprising administering to said mammal a) a first agent that is an agonist at mu and delta opioid receptors when they are expressed alone or when the mu and delta opioid receptors are expressed together in cell lines; and/or b) a second agent that is an agonist only when the mu and delta opioid receptors are expressed together but not when they are expressed alone; wherein said first agent and said second agent is not naloxone or a naloxone derivative.

52. The method of claim 51 , wherein said second agent is an inverse agonist at delta opioid receptors when these receptors are expressed alone.

53. The method of claim 51 , wherein said first agent or said second agent is selected from the group consisting of SNC 80 [(+)-4-[(alphaR)-alpha-((2S,5R)-4-Allyl- 2,5-dimethyl-l-piperazinyl)-3-methoxybenzyl]-N,N-diethylbenzamide], TIPP, Dmt-Tic- OH, N,N(CH3)2-Dmt-Tic-NH₂, Tan67, [D-Pen(2,5)]-enkephalin, DPDPE, H-Try-d-Ala- Phe-Glu- VaI-GIy-NH₂, Deltorphin π, BUBU, deltorphin I, [D-Met²]-deltorphin, SoRI 9409, SoRI 20411 , and SoRI 2404.

54. The method of claim 51, comprising administering said first agent in conjunction with said second agent.

55. The method of claim 51, wherein said first agent or said second agent is selected from the agents of any one of Tables 1 through 5.

56. A kit for mitigating one or more components of addictive behavior associated with chronic consumption of a substance of abuse, or withdrawal therefrom, by a mammal, said kit comprising: a container containing: a) a first agent that is an agonist at mu and delta opioid receptors when they are expressed alone or when the mu and delta opioid receptors are expressed together in cell lines; and/or b) a second agent that is an agonist only when the mu and delta opioid receptors are expressed together but not when they are expressed alone; and instructional materials teaching the use of said first agent and/or said second agent for mitigating one or more components of an addictive behavior and/or for inducing weight loss.

57. The kit of claim 56, wherein said second agent is an inverse agonist at delta opioid receptors when these receptors are expressed alone.

58. The kit of claim 56, wherein said first agent or said second agent is selected from the group consisting of SNC 80 [(+)-4-[(alphaR)-alpha-((2S,5R)-4-Allyl-2,5- dimethyl-l-piperazinyl)-3-methoxybenzyl]-N,N-diethylbenzamide], TIPP, Dmt-Tic-OH, N,N(CH3)2-Dmt-Tic-NH₂, Tan67, [D-Pen(2,5)]-enkephalin, DPDPE, H-Try-d-Ala-Phe- GIu-VaI-GIy-NH₂, Deltorphin π, BUBU, deltorphin I, [D-Met²]-deltorphin, SoRI 9409, SoRI 20411, and SoRI 2404.

59. The kit of claim 56, wherein said first agent or said second agent is selected from the agents of any one of Tables 1 through 5.

60. The kit of claim 56, wherein said kit additionally comprises a delta opioid receptor antagonist.

61. The kit of claim 56, wherein said first agent and/or said second agent is formulated with a pharmacologically acceptable excipient.

62. The kit of claim 56, wherein said said first agent and/or said second agent is in a unit dosage formulation.

63. The kit of claim 56, wherein said substance of abuse is ethanol.

64. The kit of claim 56, wherein said component of addictive behavior is chronic self-administration of said substance of abuse.

65. The kit of claim 56, wherein said component of addictive behavior is craving for said substance of abuse.

66. The kit of claim 56, wherein said component of addictive behavior is reinstatement of seeking behavior for said substance of abuse.

67. The kit of claim 56, wherein said first agent comprises SoRI 20144 or a derivative thereof.

68. The kit of claim 56, wherein said first agent comprises SoRI 20144.

69. The kit of claim 56, wherein said second agent comprises SoRI 9409 or a derivative thereof.

70. The kit of claim 56, wherein said second agent comprises SoRI 9409.

71. A method of screening for an agent that inhibits consumption of alcohol, said method comprising; screening a test agent for: a first agonist activity at mu and delta opioid receptors when they are expressed alone or when the mu and delta opioid receptors are expressed together in cell lines; and/or a second agonist activity only when the mu and delta opioid receptors are expressed together but not when they are expressed alone; and where agents that show said first agonist activity and/or said second agonist activity are putative agents for inhibiting consumption of alcohol.

72. The method of claim 71, wherein said method comprises screening cells that are transfected to express a heterologous mu opioid receptor and/or a heterologous delta opioid receptor.

73. The method of claim 71, wherein said method comprises measuring phosphorylation of the receptor.