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Marcus MM, Banks ML. Mechanistic and translational insights from preclinical cocaine choice procedures on the economic substitutability of cocaine and nondrug reinforcers. Neurosci Biobehav Rev 2025; 175:106217. [PMID: 40409443 DOI: 10.1016/j.neubiorev.2025.106217] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2024] [Revised: 05/08/2025] [Accepted: 05/16/2025] [Indexed: 05/25/2025]
Abstract
Substance use disorders are increasingly being conceptualized as behavioral misallocation disorders; however, the neurobiological determinants of this behavioral misallocation are poorly understood. Cocaine use disorder (CUD) develops as a result of behavior being disproportionally directed towards the procurement and use of cocaine at the expense of behaviors maintained by more adaptive, nondrug reinforcers (i.e., job, family). Preclinical cocaine-vs-nondrug reinforcer choice procedures are uniquely positioned to 1) elucidate the biological mechanisms of drug and nondrug reinforcement and 2) inform the development of effective pharmacological and behavioral CUD therapies. Accordingly, this review addresses the existing preclinical literature regarding the economic substitutability and mesolimbic dopaminergic mechanisms underlying cocaine self-administration in the context of three different concurrently available nondrug reinforcers: food, social interaction, and electric foot shock (a negative reinforcer). The manuscript focuses on how the existing cocaine-vs-nondrug reinforcer choice literature guides future research directions to facilitate advances in understanding of CUD from both a neuroscience and translational research perspective.
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Affiliation(s)
- Madison M Marcus
- Virginia Commonwealth University, Institute for Drug and Alcohol Studies, USA; Virginia Commonwealth University, Institute for Women's Health, USA; Virginia Commonwealth University, Department of Pharmacology and Toxicology, USA.
| | - Matthew L Banks
- Virginia Commonwealth University, Department of Pharmacology and Toxicology, USA
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Rahimi O, Cao J, Lam J, Childers SR, Rais R, Porrino LJ, Newman AH, Nader MA. The Effects of the Dopamine Transporter Ligands JJC8-088 and JJC8-091 on Cocaine versus Food Choice in Rhesus Monkeys. J Pharmacol Exp Ther 2023; 384:372-381. [PMID: 36507847 PMCID: PMC9976790 DOI: 10.1124/jpet.122.001363] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2022] [Revised: 11/26/2022] [Accepted: 11/30/2022] [Indexed: 12/12/2022] Open
Abstract
Although there are no Food and Drug Administration-approved treatments for cocaine use disorder, several modafinil analogs have demonstrated promise in reducing cocaine self-administration and reinstatement in rats. Furthermore, the range of dopamine transporter (DAT) compounds provides an opportunity to develop pharmacotherapeutics without abuse liability. This study extended the comparison of JJC8-088 and JJC8-091, the former compound having higher DAT affinity and predicted abuse liability, to rhesus monkeys using a concurrent cocaine versus food schedule of reinforcement. First, binding to striatal DAT was examined in cocaine-naïve monkey tissue. Next, intravenous pharmacokinetics of both JJC compounds were evaluated in cocaine-experienced male monkeys (n = 3/drug). In behavioral studies, acute and chronic administration of both compounds were evaluated in these same monkeys responding under a concurrent food versus cocaine (0 and 0.003-0.1 mg/kg per injection) schedule of reinforcement. In nonhuman primate striatum, JJC8-088 had higher DAT affinity compared with JJC8-091 (14.4 ± 9 versus 2730 ± 1270 nM, respectively). Both JJC compounds had favorable plasma pharmacokinetics for behavioral assessments, with half-lives of 1.1 hours and 3.5 hours for JJC8-088 (0.7 mg/kg, i.v.) and JJC8-091 (1.9 mg/kg, i.v.), respectively. Acute treatment with both compounds shifted the cocaine dose-response curve to the left. Chronic treatment with JJC8-088 decreased cocaine choice in two of the three monkeys, whereas JJC8-091 only modestly reduced cocaine allocation in one monkey. Differences in affinities of JJC8-091 DAT binding in monkeys compared with rats may account for the poor rodent-to-monkey translation. Future studies should evaluate atypical DAT blockers in combination with behavioral interventions that may further decrease cocaine choice. SIGNIFICANCE STATEMENT: Cocaine use disorder (CUD) remains a significant public health problem with no Food and Drug Administration-approved treatments. The ability of drugs that act in the brain in a similar manner to cocaine, but with lower abuse liability, has clinical implications for a treatment of CUD.
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Affiliation(s)
- Omeed Rahimi
- Department of Physiology and Pharmacology, Wake Forest University School of Medicine, Winston-Salem, North Carolina (O.R., S.R.C., L.J.P., M.A.N.); Medicinal Chemistry Section, Molecular Targets and Medications Discovery Branch, National Institute on Drug Abuse Intramural Research Program, National Institutes of Health, Baltimore, Maryland (J.C., J.L., A.H.N.); Department of Neurology, Johns Hopkins Drug Discovery, The Johns Hopkins University School of Medicine, Baltimore, Maryland (J.L., R.R.); and EncepHeal Therapeutics, Inc., Winston-Salem, North Carolina (O.R., S.R.C.)
| | - Jianjing Cao
- Department of Physiology and Pharmacology, Wake Forest University School of Medicine, Winston-Salem, North Carolina (O.R., S.R.C., L.J.P., M.A.N.); Medicinal Chemistry Section, Molecular Targets and Medications Discovery Branch, National Institute on Drug Abuse Intramural Research Program, National Institutes of Health, Baltimore, Maryland (J.C., J.L., A.H.N.); Department of Neurology, Johns Hopkins Drug Discovery, The Johns Hopkins University School of Medicine, Baltimore, Maryland (J.L., R.R.); and EncepHeal Therapeutics, Inc., Winston-Salem, North Carolina (O.R., S.R.C.)
| | - Jenny Lam
- Department of Physiology and Pharmacology, Wake Forest University School of Medicine, Winston-Salem, North Carolina (O.R., S.R.C., L.J.P., M.A.N.); Medicinal Chemistry Section, Molecular Targets and Medications Discovery Branch, National Institute on Drug Abuse Intramural Research Program, National Institutes of Health, Baltimore, Maryland (J.C., J.L., A.H.N.); Department of Neurology, Johns Hopkins Drug Discovery, The Johns Hopkins University School of Medicine, Baltimore, Maryland (J.L., R.R.); and EncepHeal Therapeutics, Inc., Winston-Salem, North Carolina (O.R., S.R.C.)
| | - Steven R Childers
- Department of Physiology and Pharmacology, Wake Forest University School of Medicine, Winston-Salem, North Carolina (O.R., S.R.C., L.J.P., M.A.N.); Medicinal Chemistry Section, Molecular Targets and Medications Discovery Branch, National Institute on Drug Abuse Intramural Research Program, National Institutes of Health, Baltimore, Maryland (J.C., J.L., A.H.N.); Department of Neurology, Johns Hopkins Drug Discovery, The Johns Hopkins University School of Medicine, Baltimore, Maryland (J.L., R.R.); and EncepHeal Therapeutics, Inc., Winston-Salem, North Carolina (O.R., S.R.C.)
| | - Rana Rais
- Department of Physiology and Pharmacology, Wake Forest University School of Medicine, Winston-Salem, North Carolina (O.R., S.R.C., L.J.P., M.A.N.); Medicinal Chemistry Section, Molecular Targets and Medications Discovery Branch, National Institute on Drug Abuse Intramural Research Program, National Institutes of Health, Baltimore, Maryland (J.C., J.L., A.H.N.); Department of Neurology, Johns Hopkins Drug Discovery, The Johns Hopkins University School of Medicine, Baltimore, Maryland (J.L., R.R.); and EncepHeal Therapeutics, Inc., Winston-Salem, North Carolina (O.R., S.R.C.)
| | - Linda J Porrino
- Department of Physiology and Pharmacology, Wake Forest University School of Medicine, Winston-Salem, North Carolina (O.R., S.R.C., L.J.P., M.A.N.); Medicinal Chemistry Section, Molecular Targets and Medications Discovery Branch, National Institute on Drug Abuse Intramural Research Program, National Institutes of Health, Baltimore, Maryland (J.C., J.L., A.H.N.); Department of Neurology, Johns Hopkins Drug Discovery, The Johns Hopkins University School of Medicine, Baltimore, Maryland (J.L., R.R.); and EncepHeal Therapeutics, Inc., Winston-Salem, North Carolina (O.R., S.R.C.)
| | - Amy Hauck Newman
- Department of Physiology and Pharmacology, Wake Forest University School of Medicine, Winston-Salem, North Carolina (O.R., S.R.C., L.J.P., M.A.N.); Medicinal Chemistry Section, Molecular Targets and Medications Discovery Branch, National Institute on Drug Abuse Intramural Research Program, National Institutes of Health, Baltimore, Maryland (J.C., J.L., A.H.N.); Department of Neurology, Johns Hopkins Drug Discovery, The Johns Hopkins University School of Medicine, Baltimore, Maryland (J.L., R.R.); and EncepHeal Therapeutics, Inc., Winston-Salem, North Carolina (O.R., S.R.C.)
| | - Michael A Nader
- Department of Physiology and Pharmacology, Wake Forest University School of Medicine, Winston-Salem, North Carolina (O.R., S.R.C., L.J.P., M.A.N.); Medicinal Chemistry Section, Molecular Targets and Medications Discovery Branch, National Institute on Drug Abuse Intramural Research Program, National Institutes of Health, Baltimore, Maryland (J.C., J.L., A.H.N.); Department of Neurology, Johns Hopkins Drug Discovery, The Johns Hopkins University School of Medicine, Baltimore, Maryland (J.L., R.R.); and EncepHeal Therapeutics, Inc., Winston-Salem, North Carolina (O.R., S.R.C.)
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Nader MA. The impact of social variables in preclinical models of cocaine abuse. Fac Rev 2021; 10:76. [PMID: 34746929 PMCID: PMC8546596 DOI: 10.12703/r/10-76] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
At present, there are no US Food and Drug Administration–approved treatments for cocaine use disorders. One consideration for this lack of treatment efficacy stems from the appropriate use of animal models. The premise of this commentary is that social behavior needs to be incorporated in animal models of cocaine use disorder. The goal of this commentary is to describe some of the strengths and limitations of recent preclinical animal models of cocaine abuse which have incorporated social behavior. There are many ways to include social variables into preclinical research, and the study design will depend on the questions asked. Four general types of studies incorporating social factors are described: those involving aggression (that is, maternal neglect and social defeat), modeling, social reward, and social housing, including social isolation. The inclusion of social variables into preclinical research will help identify biobehavioral markers that may lead to an individualized treatment approach that more effectively decreases cocaine use. These studies will aid in the development of novel pharmacotherapies as well as non-pharmacological interventions (for example, punishment, alternative reinforcers, and environmental enrichment) that would be critical for informing policy decisions.
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Affiliation(s)
- Michael A Nader
- Department of Physiology and Pharmacology, Wake Forest School of Medicine, 546 NRC, Medical Center Boulevard, Winston-Salem, NC 27157-1083, USA
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Negus SS, Banks ML. Confronting the challenge of failed translation in medications development for substance use disorders. Pharmacol Biochem Behav 2021; 210:173264. [PMID: 34461148 PMCID: PMC8418188 DOI: 10.1016/j.pbb.2021.173264] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Accepted: 08/20/2021] [Indexed: 11/25/2022]
Affiliation(s)
- S S Negus
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, VA, United States of America.
| | - M L Banks
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, VA, United States of America
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Czoty PW, Nader MA. Effects of Dopamine D1-Like Receptor Ligands on Food-Cocaine Choice in Socially Housed Male Cynomolgus Monkeys. J Pharmacol Exp Ther 2021; 379:12-19. [PMID: 34272270 PMCID: PMC8626634 DOI: 10.1124/jpet.121.000701] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2021] [Accepted: 07/12/2021] [Indexed: 11/22/2022] Open
Abstract
Although dopamine plays a prominent role in mediating cocaine's abuse-related effects, the specific roles of dopamine receptor subtypes are not fully understood. Whereas the effects of drugs acting at dopamine D2-like receptors (D2Rs) have been characterized, less is known about dopamine D1-like receptors (D1Rs). The present experiments examined the effects of drugs with varying intrinsic efficacy at D1R on the relative reinforcing strength of cocaine in male cynomolgus monkeys. Use of socially housed monkeys permitted the assessment of whether social status influenced the behavioral effects of D1R-acting drugs. The high-efficacy D1R agonist SKF 81297, low-efficacy D1R agonist SKF 38393, and D1R antagonist SCH 23390 were administered acutely to monkeys self-administering cocaine under a food-cocaine choice procedure in which a cocaine-choice dose-effect curve was determined daily. To assess selectivity of behavioral effects on cocaine choice, effects of doses that did not disrupt responding (indicated by a ≥35% decrease in total reinforcers delivered) were analyzed. Neither SKF 81297 nor SCH 23390 affected cocaine choice in dominant or subordinate monkeys. However, the low-efficacy agonist SKF 38393 selectively decreased cocaine choice; this effect was larger and only reached statistical significance in subordinate monkeys. Increasing the time between D1-acting drug administration and the cocaine choice session did not affect these results. The results indicate that, like D2R-acting drugs, the behavioral effects of D1R-acting drugs on cocaine choice can vary according to intrinsic efficacy and social status. Moreover, they demonstrate that D1R-acting drugs affect behavior under a narrower range of conditions than D2R-acting drugs. SIGNIFICANCE STATEMENT: Cocaine use disorder represents an insidious public health concern with no Food and Drug Administration-approved medications. Although dopamine receptors have been strongly implicated in mediating the abuse-related effects of cocaine, the roles of dopamine receptor subtypes are incompletely understood. The present study in nonhuman primates found that cocaine choice was decreased only by a low-efficacy D1R agonist, and that this effect depended on the social status of the monkey.
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Affiliation(s)
- Paul W Czoty
- Department of Physiology and Pharmacology Wake Forest School of Medicine, Winston-Salem, North Carolina
| | - Michael A Nader
- Department of Physiology and Pharmacology Wake Forest School of Medicine, Winston-Salem, North Carolina
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Negus SS, Banks ML. Learning from lorcaserin: lessons from the negative clinical trial of lorcaserin to treat cocaine use disorder. Neuropsychopharmacology 2020; 45:1967-1973. [PMID: 32839526 PMCID: PMC7547654 DOI: 10.1038/s41386-020-00815-4] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Revised: 08/10/2020] [Accepted: 08/12/2020] [Indexed: 11/09/2022]
Affiliation(s)
- S. Stevens Negus
- grid.224260.00000 0004 0458 8737Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, VA 23298 USA
| | - Matthew L. Banks
- grid.224260.00000 0004 0458 8737Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, VA 23298 USA
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Czoty PW, Nader MA. Effects of the α-2 Adrenergic Receptor Agonists Lofexidine and Guanfacine on Food-Cocaine Choice in Socially Housed Cynomolgus Monkeys. J Pharmacol Exp Ther 2020; 375:193-201. [PMID: 32636208 PMCID: PMC7569305 DOI: 10.1124/jpet.120.266007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2020] [Accepted: 07/02/2020] [Indexed: 11/22/2022] Open
Abstract
Although norepinephrine (NE) does not appear to play a prominent role in mediating the abuse-related effects of cocaine, studies have indicated that NE α-2 receptor agonists can attenuate reinstatement of extinguished cocaine self-administration in rats and monkeys and can decrease cocaine craving in humans. In the present studies, we examined the effects of two α-2 receptor agonists, lofexidine and guanfacine, on choice between food and cocaine (0.0-0.1 mg/kg per injection) in cynomolgus monkeys. Male and female subjects were housed in stable same-sex social groups of four; social rank did not influence the effects of lofexidine and guanfacine. When administered acutely, lofexidine (0.03-3.0 mg/kg, i.v.) significantly decreased cocaine choice in females (n = 7) but not males (n = 8). However, in males, the same lofexidine doses produced dose-dependent decreases in core body temperature (n = 7), and acute guanfacine (0.003-1.0 mg/kg, i.v.) significantly decreased cocaine choice (n = 11). When lofexidine was administered for five consecutive days to a subset of the monkeys in whom lofexidine acutely decreased cocaine choice, tolerance to this effect developed to varying degrees of completeness in three of three males and two of four females. Taken together, these data suggest that α-2 receptor agonists can produce small decreases in the reinforcing strength of cocaine relative to food and that, even when efficacy is observed after acute administration, tolerance to the decreases in cocaine choice are apparent and more likely in males compared with females. SIGNIFICANCE STATEMENT: Cocaine use disorder remains a significant public health problem with no US Food and Drug Administration-approved treatments. Although cocaine elevates dopamine, serotonin, and norepinephrine (NE), the latter target has received less research. The present study noted modest effects of NE agonists on the relative reinforcing strength of cocaine with greater efficacy in female compared with male monkeys.
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Affiliation(s)
- Paul W Czoty
- Department of Physiology and Pharmacology, Wake Forest School of Medicine, Winston-Salem, North Carolina
| | - Michael A Nader
- Department of Physiology and Pharmacology, Wake Forest School of Medicine, Winston-Salem, North Carolina
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Vannan A, Powell GL, Scott SN, Pagni BA, Neisewander JL. Animal Models of the Impact of Social Stress on Cocaine Use Disorders. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2018; 140:131-169. [PMID: 30193703 DOI: 10.1016/bs.irn.2018.07.005] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Cocaine use disorders are strongly influenced by the social conditions prior, during, and after exposure to cocaine. In this chapter, we discuss how social factors such as early life stress, social rank stress, and environmental stress impact vulnerability and resilience to cocaine. The discussion of each animal model begins with a brief review of examples from the human literature, which provide the psychosocial background these models attempt to capture. We then discuss preclinical findings from use of each model, with emphasis on how social factors influence cocaine-related behaviors and how sex and age influence the behaviors and neurobiology. Models discussed include (1) early life social stress, such as maternal separation and neonatal isolation, (2) social defeat stress, (3) social hierarchies, and (4) social isolation and environmental enrichment. The cocaine-related behaviors reviewed for each of these animal models include cocaine-induced conditioned place preference, behavioral sensitization, and self-administration. Together, our review suggests that the degree of psychosocial stress experienced yields robust effects on cocaine-related behaviors and neurobiology, and these preclinical findings have translational impact for the future of cocaine use disorder treatment.
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Affiliation(s)
- Annika Vannan
- School of Life Sciences, Arizona State University, Tempe, AZ, United States
| | - Gregory L Powell
- School of Life Sciences, Arizona State University, Tempe, AZ, United States
| | - Samantha N Scott
- School of Life Sciences, Arizona State University, Tempe, AZ, United States
| | - Broc A Pagni
- School of Life Sciences, Arizona State University, Tempe, AZ, United States
| | - Janet L Neisewander
- School of Life Sciences, Arizona State University, Tempe, AZ, United States.
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Perkins FN, Freeman KB. Pharmacotherapies for decreasing maladaptive choice in drug addiction: Targeting the behavior and the drug. Pharmacol Biochem Behav 2018; 164:40-49. [PMID: 28666892 PMCID: PMC5745300 DOI: 10.1016/j.pbb.2017.06.015] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/02/2017] [Revised: 06/06/2017] [Accepted: 06/26/2017] [Indexed: 12/23/2022]
Abstract
Drug addiction can be conceptualized as a disorder of maladaptive decision making in which drugs are chosen at the expense of pro-social, nondrug alternatives. The study of decision making in drug addiction has focused largely on the role of impulsivity as a facilitator of addiction, in particular the tendency for drug abusers to choose small, immediate gains over larger but delayed outcomes (i.e., delay discounting). A parallel line of work, also focused on decision making in drug addiction, has focused on identifying the determinants underlying the choice to take drugs over nondrug alternatives (i.e., drug vs. nondrug choice). Both tracks of research have been valuable tools in the development of pharmacotherapies for treating maladaptive decision making in drug addiction, and a number of common drugs have been studied in both designs. However, we have observed that there is little uniformity in the administration regimens of potential treatments between the designs, which hinders congruence in the development of single treatment strategies to reduce both impulsive behavior and drug choice. The current review provides an overview of the drugs that have been tested in both delay-discounting and drug-choice designs, and focuses on drugs that reduced the maladaptive choice in both designs. Suggestions to enhance congruence between the findings in future studies are provided. Finally, we propose the use of a hybridized, experimental approach that may enable researchers to test the effectiveness of therapeutics at decreasing impulsive and drug choice in a single design.
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Affiliation(s)
- Frank N Perkins
- Division of Neurobiology and Behavior Research, Department of Psychiatry and Human Behavior, University of Mississippi Medical Center, Jackson, MS 39216, United States
| | - Kevin B Freeman
- Division of Neurobiology and Behavior Research, Department of Psychiatry and Human Behavior, University of Mississippi Medical Center, Jackson, MS 39216, United States.
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Late Reduction of Cocaine Cravings in a Randomized, Double-Blind Trial of Aripiprazole vs Perphenazine in Schizophrenia and Comorbid Cocaine Dependence. J Clin Psychopharmacol 2017; 37:657-663. [PMID: 28984746 DOI: 10.1097/jcp.0000000000000789] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
PURPOSE Co-occurring schizophrenia spectrum disorder and International Statistical Classification of Diseases, 10th Revision cocaine dependence present a particularly destructive constellation that is often difficult to treat. Both conditions raise dopamine transmission effects in the brain. Traditional neuroleptics block dopamine receptors, whereas aripiprazole modulates dopamine activity as an agonist/antagonist. We tested whether dopamine modulation is superior to dopamine blocking in dual-diagnosis patients. METHODS In a randomized, double-blind, comparison design, cocaine-dependent schizophrenic subjects actively using cocaine received either aripiprazole or perphenazine in an 8-week trial. Primary outcome targeted cocaine-free urine sample proportions, whereas cocaine craving scores were a secondary variable. RESULTS Subjects (N = 44) randomized (n = 22 per group) did not differ at baseline. The proportion of cocaine-free urine samples did not differ by medication group. Contrasting weeks 3 to 5 vs 6 to 8 revealed significant late reductions in craving with aripiprazole. On the respective 5-point subscales, craving intensity decreased by 1.53 ± 0.43 (P < 0.0005) points, craving frequency by 1.4 ± 0.40 (P > 0.0004) points, and craving duration by 1.76 ± 0.44 (P > 0.0001) points. CONCLUSIONS A drug effect of aripiprazole on craving items appeared at week 6 of treatment, on average, and was not seen before that length of drug exposure. The data suggest that dopamine modulation reduces cocaine cravings but requires an acclimation period. To understand the mechanism of action better, a trial of depot aripiprazole may be useful. Clinically, a reduction in craving potentially offers a clearer focus for ongoing behavioral treatment. It may also offer a longer-term treatment effect with respect to the severity of relapse.
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Czoty PW, Gould RW, Gage HD, Nader MA. Effects of social reorganization on dopamine D2/D3 receptor availability and cocaine self-administration in male cynomolgus monkeys. Psychopharmacology (Berl) 2017; 234:2673-2682. [PMID: 28608008 PMCID: PMC5709179 DOI: 10.1007/s00213-017-4658-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/04/2017] [Accepted: 05/21/2017] [Indexed: 12/14/2022]
Abstract
RATIONALE Studies have demonstrated that brain dopamine D2/D3 receptors (D2/D3R) and the reinforcing effects of cocaine can be influenced by a monkey's position in the social dominance hierarchy. OBJECTIVE In this study, we manipulated the social ranks of monkeys by reorganizing social groups and assessed effects on D2/D3R availability and cocaine self-administration. METHODS Male cynomolgus monkeys (N = 12) had been trained to self-administer cocaine under a concurrent cocaine-food reinforcement schedule. Previously, PET measures of D2/D3R availability in the caudate nucleus and putamen had been obtained with [18F]fluoroclebopride during cocaine abstinence, while monkeys lived in stable social groups of four monkeys/pen. For this study, monkeys were reorganized into groups that consisted of (1) four previously dominant, (2) four previously subordinate, and (3) a mix of previously dominant and subordinate monkeys. After 3 months, D2/D3R availability was redetermined and cocaine self-administration was reexamined. RESULTS D2/D3R availability significantly increased after reorganization in monkeys who were formerly subordinate, with the greatest increases observed in those that became dominant. No consistent changes in D2/D3R availability were observed in formerly dominant monkeys. Cocaine self-administration did not vary according to rank after reorganization of social groups. However, when compared to their previous cocaine self-administration data, the potency of cocaine as a reinforcer decreased in 9 of 11 monkeys. CONCLUSIONS These results indicate that changing the social conditions can alter D2/D3R availability in subordinate monkeys in a manner suggestive of environmental enrichment. In most monkeys, social reorganization shifted the cocaine dose-response curve to the right, also consistent with environmental enrichment.
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Affiliation(s)
- P W Czoty
- Department of Physiology and Pharmacology, Wake Forest School of Medicine, Medical Center Boulevard, 546 NRC, Winston-Salem, NC, 27157-1083, USA
| | - R W Gould
- Department of Physiology and Pharmacology, Wake Forest School of Medicine, Medical Center Boulevard, 546 NRC, Winston-Salem, NC, 27157-1083, USA
| | - H D Gage
- Department of Radiology, Wake Forest School of Medicine, Winston-Salem, NC, 27157, USA
| | - M A Nader
- Department of Physiology and Pharmacology, Wake Forest School of Medicine, Medical Center Boulevard, 546 NRC, Winston-Salem, NC, 27157-1083, USA.
- Department of Radiology, Wake Forest School of Medicine, Winston-Salem, NC, 27157, USA.
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13
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Thomsen M, Barrett AC, Butler P, Negus SS, Caine SB. Effects of Acute and Chronic Treatments with Dopamine D 2 and D 3 Receptor Ligands on Cocaine versus Food Choice in Rats. J Pharmacol Exp Ther 2017; 362:161-176. [PMID: 28473458 PMCID: PMC5469403 DOI: 10.1124/jpet.117.241141] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2017] [Accepted: 04/20/2017] [Indexed: 02/01/2023] Open
Abstract
Dopamine D3 receptor ligands are potential medications for psychostimulant addiction. Medication assessment may benefit from preclinical studies that evaluate chronic medication effects on choice between an abused drug and an alternative, nondrug reinforcer. This study compared acute and chronic effects of dopamine D2- and D3-preferring ligands on choice between intravenous cocaine and palatable food in rats. Under baseline conditions, cocaine maintained dose-dependent increases in cocaine choice and reciprocal decreases in food choice. Acutely, the D2 agonist R-(-)-norpropylapomorphine (NPA) and antagonist L-741,626 [3-[[4-(4-chlorophenyl)-4-hydroxypiperidin-l-yl]methyl-1H-indole] produced leftward and rightward shifts in cocaine dose-effect curves, respectively, whereas the partial agonist terguride had no effect. All three drugs dose-dependently decreased food-maintained responding. Chronically, the effects of R-(-)-norpropylapomorphine and L-741,626 on cocaine self-administration showed marked tolerance, whereas suppression of food-reinforced behavior persisted. Acute effects of the D3 ligands were less systematic and most consistent with nonselective decreases in cocaine- and food-maintained responding. Chronically, the D3 agonist PF-592,379 [5-[(2R,5S)-5-methyl-4-propylmorpholin-2-yl]pyridin-2-amine] increased cocaine choice, whereas an intermediate dose of the D3 antagonist PG01037 [N-[(E)-4-[4-(2,3-dichlorophenyl)piperazin-1-yl]but-2-enyl]-4-pyridin-2-ylbenzamide] produced a therapeutically desirable decrease in cocaine choice early in treatment; however, tolerance to this effect developed, and lower and higher doses were ineffective. D3 ligands failed to significantly modify total cocaine intake but caused persistent decreases in food intake. Thus, D2-and D3-preferring ligands showed distinct profiles, consistent with different pharmacological actions. In addition, these results highlight the role of acute versus chronic treatment as a determinant of test drug effects. With the possible exception of the D3 antagonist PG01037, no ligand was promising in terms of cocaine addiction treatment.
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Affiliation(s)
- Morgane Thomsen
- Alcohol and Drug Abuse Research Center, McLean Hospital, Belmont, Massachusetts (M.T., A.C.B., S.B.C.); Department of Psychiatry, Harvard Medical School, Belmont, Massachusetts (M.T., A.C.B., S.B.C.); Laboratory of Neuropsychiatry, Psychiatric Centre Copenhagen, University of Copenhagen, Copenhagen, Denmark (M.T.); Drug Safety Research and Development, Pfizer, San Diego, California (P.B.); and Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, Virginia (S.S.N.)
| | - Andrew C Barrett
- Alcohol and Drug Abuse Research Center, McLean Hospital, Belmont, Massachusetts (M.T., A.C.B., S.B.C.); Department of Psychiatry, Harvard Medical School, Belmont, Massachusetts (M.T., A.C.B., S.B.C.); Laboratory of Neuropsychiatry, Psychiatric Centre Copenhagen, University of Copenhagen, Copenhagen, Denmark (M.T.); Drug Safety Research and Development, Pfizer, San Diego, California (P.B.); and Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, Virginia (S.S.N.)
| | - Paul Butler
- Alcohol and Drug Abuse Research Center, McLean Hospital, Belmont, Massachusetts (M.T., A.C.B., S.B.C.); Department of Psychiatry, Harvard Medical School, Belmont, Massachusetts (M.T., A.C.B., S.B.C.); Laboratory of Neuropsychiatry, Psychiatric Centre Copenhagen, University of Copenhagen, Copenhagen, Denmark (M.T.); Drug Safety Research and Development, Pfizer, San Diego, California (P.B.); and Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, Virginia (S.S.N.)
| | - S Stevens Negus
- Alcohol and Drug Abuse Research Center, McLean Hospital, Belmont, Massachusetts (M.T., A.C.B., S.B.C.); Department of Psychiatry, Harvard Medical School, Belmont, Massachusetts (M.T., A.C.B., S.B.C.); Laboratory of Neuropsychiatry, Psychiatric Centre Copenhagen, University of Copenhagen, Copenhagen, Denmark (M.T.); Drug Safety Research and Development, Pfizer, San Diego, California (P.B.); and Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, Virginia (S.S.N.)
| | - S Barak Caine
- Alcohol and Drug Abuse Research Center, McLean Hospital, Belmont, Massachusetts (M.T., A.C.B., S.B.C.); Department of Psychiatry, Harvard Medical School, Belmont, Massachusetts (M.T., A.C.B., S.B.C.); Laboratory of Neuropsychiatry, Psychiatric Centre Copenhagen, University of Copenhagen, Copenhagen, Denmark (M.T.); Drug Safety Research and Development, Pfizer, San Diego, California (P.B.); and Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, Virginia (S.S.N.)
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Zernig G, Hiemke C. Making the Case for 'Power Abuse Disorder' as a Nosologic Entity. Pharmacology 2017; 100:50-63. [PMID: 28467994 DOI: 10.1159/000475600] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2017] [Accepted: 04/10/2017] [Indexed: 12/18/2022]
Abstract
The development of societies and cultures arguably is based on the ability of human primates to form hierarchies in which some individuals acquire and wield power, that is, control resources and influence and control the behavior of their conspecifics. In the following, we focus on the type of human primate power wielding that (a) harms and (b) produces excessive negative emotions in (1) the victim(s) of the power wielder and (2) the power wielder her/himself. If such a harmful behavior of the power wielder is not accompanied by an ethically justifiable benefit for the involved human primate groups, it can be considered "power abuse." We propose to term the associated behaviors, cognitions, and emotions of the power wielder as "power abuse disorder" (PAD). This behavior results from what we consider addictive behavior of the power abuse disordered (PADed) power wielder. PAD can be diagnosed on the basis of the World Health Organization's criteria for "dependence syndrome" as listed in the International Classification of Diseases version 10. We will demonstrate that many PADed individuals may very likely carry the Zeitgeist diagnosis "burnout." This article reviews the current understanding of the neural correlates of PAD and suggests future research. Based on the available evidence, PAD seems to be associated with a dysfunction of the mesocorticolimbic dopamine system, rendering PADed individuals vulnerable for psychostimulant abuse/dependence, and suggesting specific pharmacotherapeutic approaches to treat PAD.
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Affiliation(s)
- Gerald Zernig
- Experimental Psychiatry Unit, Department of Psychiatry 1, Medical University of Innsbruck, Innsbruck, Austria
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Gould RW, Czoty PW, Porrino LJ, Nader MA. Social Status in Monkeys: Effects of Social Confrontation on Brain Function and Cocaine Self-Administration. Neuropsychopharmacology 2017; 42:1093-1102. [PMID: 28025974 PMCID: PMC5506801 DOI: 10.1038/npp.2016.285] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/29/2016] [Revised: 12/05/2016] [Accepted: 12/11/2016] [Indexed: 12/23/2022]
Abstract
Individual differences in response to social stress and environmental enrichment may contribute to variability in response to behavioral and pharmacological treatments for drug addiction. In monkeys, social status influences the reinforcing effects of cocaine and the effects of some drugs on cocaine self-administration. In this study, we used male cynomolgus macaques (n=15) living in established social groups to examine the effects of social confrontation on the reinforcing effects of cocaine using a food-drug choice procedure. On the test day, a dominant or subordinate monkey was removed from his homecage and placed into another social pen; 30 min later he was studied in a cocaine-food choice paradigm. For the group, following social confrontation, sensitivity to cocaine reinforcement was significantly greater in subordinate monkeys compared with dominant animals. Examining individual-subject data revealed that for the majority of monkeys (9/15), serving as an intruder in another social group affected cocaine self-administration and these effects were dependent on the social rank of the monkey. For subordinate monkeys, sensitivity to the reinforcing effects of cocaine increased while sensitivity decreased in dominant monkeys. To investigate potential mechanisms mediating these effects, brain glucose metabolism was studied in a subset of monkeys (n=8) using [18F]fluorodeoxyglucose ([18F]FDG) with positron emission tomography. Dominant and subordinate monkeys displayed distinctly different patterns of brain glucose metabolism in their homecage, including areas associated with vigilance and stress/anxiety, respectively, and during social confrontation. These data demonstrate that, depending on an individual's social status, the same social experience can have divergent effects on brain function and cocaine self-administration. These phenotypic differences in response to social conditions support a personalized treatment approach to cocaine addiction.
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Affiliation(s)
- Robert W Gould
- Department of Physiology and Pharmacology, Wake Forest School of Medicine, Winston-Salem, NC, USA
| | - Paul W Czoty
- Department of Physiology and Pharmacology, Wake Forest School of Medicine, Winston-Salem, NC, USA
| | - Linda J Porrino
- Department of Physiology and Pharmacology, Wake Forest School of Medicine, Winston-Salem, NC, USA
| | - Michael A Nader
- Department of Physiology and Pharmacology, Wake Forest School of Medicine, Winston-Salem, NC, USA
- Department of Radiology, Wake Forest School of Medicine, Winston-Salem, NC, USA
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Cortés A, Moreno E, Rodríguez-Ruiz M, Canela EI, Casadó V. Targeting the dopamine D3 receptor: an overview of drug design strategies. Expert Opin Drug Discov 2016; 11:641-64. [PMID: 27135354 DOI: 10.1080/17460441.2016.1185413] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
INTRODUCTION Dopamine is a neurotransmitter widely distributed in both the periphery and the central nervous system (CNS). Its physiological effects are mediated by five closely related G protein-coupled receptors (GPCRs) that are divided into two major subclasses: the D1-like (D1, D5) and the D2-like (D2, D3, D4) receptors. D3 receptors (D3Rs) have the highest density in the limbic areas of the brain, which are associated with cognitive and emotional functions. These receptors are therefore attractive targets for therapeutic management. AREAS COVERED This review summarizes the functional and pharmacological characteristics of D3Rs, including the design and clinical relevance of full agonists, partial agonists and antagonists, as well as the capacity of these receptors to form active homodimers, heterodimers or higher order receptor complexes as pharmacological targets in several neurological and neurodegenerative disorders. EXPERT OPINION The high sequence homology between D3R and the D2-type challenges the development of D3R-selective compounds. The design of new D3R-preferential ligands with improved physicochemical properties should provide a better pharmacokinetic/bioavailability profile and lesser toxicity than is found with existing D3R ligands. It is also essential to optimize D3R affinity and, especially, D3R vs. D2-type binding and functional selectivity ratios. Developing allosteric and bitopic ligands should help to improve the D3R selectivity of these drugs. As most evidence points to the ability of GPCRs to form homomers and heteromers, the most promising therapeutic strategy in the future is likely to involve the application of heteromer-selective drugs. These selective ligands would display different affinities for a given receptor depending on the receptor partners within the heteromer. Therefore, designing novel compounds that specifically target and modulate D1R-D3R heteromers would be an interesting approach for the treatment of levodopa (L-DOPA)-induced dyskinesias.
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Affiliation(s)
- Antoni Cortés
- a Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED) , Spain.,b Department of Biochemistry and Molecular Biomedicine, Faculty of Biology, Institute of Biomedicine of the University of Barcelona (IBUB) , University of Barcelona , Barcelona , Spain
| | - Estefanía Moreno
- a Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED) , Spain.,b Department of Biochemistry and Molecular Biomedicine, Faculty of Biology, Institute of Biomedicine of the University of Barcelona (IBUB) , University of Barcelona , Barcelona , Spain
| | - Mar Rodríguez-Ruiz
- a Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED) , Spain.,b Department of Biochemistry and Molecular Biomedicine, Faculty of Biology, Institute of Biomedicine of the University of Barcelona (IBUB) , University of Barcelona , Barcelona , Spain
| | - Enric I Canela
- a Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED) , Spain.,b Department of Biochemistry and Molecular Biomedicine, Faculty of Biology, Institute of Biomedicine of the University of Barcelona (IBUB) , University of Barcelona , Barcelona , Spain
| | - Vicent Casadó
- a Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED) , Spain.,b Department of Biochemistry and Molecular Biomedicine, Faculty of Biology, Institute of Biomedicine of the University of Barcelona (IBUB) , University of Barcelona , Barcelona , Spain
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Hutsell BA, Cheng K, Rice KC, Negus SS, Banks ML. Effects of the kappa opioid receptor antagonist nor-binaltorphimine (nor-BNI) on cocaine versus food choice and extended-access cocaine intake in rhesus monkeys. Addict Biol 2016; 21:360-73. [PMID: 25581305 DOI: 10.1111/adb.12206] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
The dynorphin/kappa opioid receptor (KOR) system has been implicated as one potential neurobiological modulator of the abuse-related effects of cocaine and as a potential target for medications development. This study determined effects of the KOR antagonist nor-binaltorphimine (nor-BNI) on cocaine self-administration under a novel procedure that featured two daily components: (1) a 2-hour 'choice' component (9:00-11:00 am) when monkeys could choose between food pellets and cocaine injections (0-0.1 mg/kg per injection, intravenous) and (2) a 20-hour 'extended-access' component (noon to 8:00 am) when cocaine (0.1 mg/kg per injection) was available under a fixed-ratio schedule to promote high daily cocaine intakes. Rhesus monkeys (n = 4) were given 14 days of exposure to the choice + extended-access procedure then treated with nor-BNI (3.2 or 10.0 mg/kg, intramuscular), and cocaine choice and extended-access cocaine intake were evaluated for an additional 14 days. Consistent with previous studies, cocaine maintained both a dose-dependent increase in cocaine choice during choice components and a high level of cocaine intake during extended-access components. Neither 3.2 nor 10 mg/kg nor-BNI significantly altered cocaine choice or extended-access cocaine intake. In two additional monkeys, nor-BNI also had no effect on cocaine choice or extended-access cocaine intake when it was administered at the beginning of exposure to the extended-access components. Overall, these results do not support a major role for the dynorphin/KOR system in modulating cocaine self-administration under these conditions in non-human primates nor do they support the clinical utility of KOR antagonists as a pharmacotherapeutic strategy for cocaine addiction.
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Affiliation(s)
- Blake A. Hutsell
- Department of Pharmacology and Toxicology; Virginia Commonwealth University; Richmond VA USA
| | - Kejun Cheng
- Chemical Biology Branch; National Institute on Alcohol Abuse and Alcoholism; National Institute of Health; Bethesda MD USA
| | - Kenner C. Rice
- Chemical Biology Branch; National Institute on Alcohol Abuse and Alcoholism; National Institute of Health; Bethesda MD USA
| | - Sidney Stevens Negus
- Department of Pharmacology and Toxicology; Virginia Commonwealth University; Richmond VA USA
- Institute for Drug and Alcohol Abuse Studies; Virginia Commonwealth University; Richmond VA USA
| | - Matthew L. Banks
- Department of Pharmacology and Toxicology; Virginia Commonwealth University; Richmond VA USA
- Institute for Drug and Alcohol Abuse Studies; Virginia Commonwealth University; Richmond VA USA
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Azorin JM, Simon N, Adida M, Belzeaux R. Pharmacological treatment of schizophrenia with comorbid substance use disorder. Expert Opin Pharmacother 2015; 17:231-53. [DOI: 10.1517/14656566.2016.1114101] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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Banks ML, Hutsell BA, Schwienteck KL, Negus SS. Use of Preclinical Drug vs. Food Choice Procedures to Evaluate Candidate Medications for Cocaine Addiction. CURRENT TREATMENT OPTIONS IN PSYCHIATRY 2015; 2:136-150. [PMID: 26009706 PMCID: PMC4441409 DOI: 10.1007/s40501-015-0042-9] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Drug addiction is a disease that manifests as an inappropriate allocation of behavior towards the procurement and use of the abused substance and away from other behaviors that produce more adaptive reinforcers (e.g. exercise, work, family and social relationships). The goal of treating drug addiction is not only to decrease drug-maintained behaviors, but also to promote a reallocation of behavior towards alternative, nondrug reinforcers. Experimental procedures that offer concurrent access to both a drug reinforcer and an alternative, nondrug reinforcer provide a research tool for assessment of medication effects on drug choice and behavioral allocation. Choice procedures are currently the standard in human laboratory research on medications development. Preclinical choice procedures have been utilized in biomedical research since the early 1940's, and during the last 10-15 years, their use for evaluation of medications to treat drug addiction has increased. We propose here that parallel use of choice procedures in preclinical and clinical studies will facilitate translational research on development of medications to treat cocaine addiction. In support of this proposition, a review of the literature suggests strong concordance between preclinical effectiveness of candidate medications to modify cocaine choice in nonhuman primates and rodents and clinical effectiveness of these medications to modify either cocaine choice in human laboratory studies or metrics of cocaine abuse in patients with cocaine use disorder. The strongest evidence for medication effectiveness in preclinical choice studies has been obtained with maintenance on the monoamine releaser d-amphetamine, a candidate agonist medication for cocaine use analogous to use of methadone to treat heroin abuse or nicotine formulations to treat tobacco dependence.
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Affiliation(s)
- Matthew L Banks
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, VA, USA
- Institute for Drug and Alcohol Abuse Studies, Virginia Commonwealth University, Richmond, VA, USA
| | - Blake A Hutsell
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, VA, USA
| | - Kathryn L Schwienteck
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, VA, USA
- School of Pharmacy, Virginia Commonwealth University, Richmond, VA, USA
| | - S. Stevens Negus
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, VA, USA
- Institute for Drug and Alcohol Abuse Studies, Virginia Commonwealth University, Richmond, VA, USA
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John WS, Newman AH, Nader MA. Differential effects of the dopamine D3 receptor antagonist PG01037 on cocaine and methamphetamine self-administration in rhesus monkeys. Neuropharmacology 2015; 92:34-43. [PMID: 25576373 PMCID: PMC4346463 DOI: 10.1016/j.neuropharm.2014.12.024] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2014] [Revised: 12/17/2014] [Accepted: 12/22/2014] [Indexed: 12/17/2022]
Abstract
The dopamine D3 receptor (D3R) has been shown to mediate many of the behavioral effects of psychostimulants associated with high abuse potential. This study extended the assessment of the highly selective D3R antagonist PG01037 on cocaine and methamphetamine (MA) self-administration to include a food-drug choice procedure. Eight male rhesus monkeys (n=4/group) served as subjects in which complete cocaine and MA dose-response curves were determined daily in each session. When choice was stable, monkeys received acute and five-day treatment of PG01037 (1.0-5.6 mg/kg, i.v.). Acute administration of PG01037 was effective in reallocating choice from cocaine to food and decreasing cocaine intake, however, tolerance developed by day 5 of treatment. Up to doses that disrupted responding, MA choice and intake were not affected by PG01037 treatment. PG01037 decreased total reinforcers earned per session and the behavioral potency was significantly greater on MA-food choice compared to cocaine-food choice. Furthermore, the acute efficacy of PG01037 was correlated with the sensitivity of the D3/D2R agonist quinpirole to elicit yawning. These data suggest (1) that efficacy of D3R compounds in decreasing drug choice is greater in subjects with lower D3R, perhaps suggesting that it is percent occupancy that is the critical variable in determining efficacy and (2) differences in D3R activity in chronic cocaine vs. MA users. Although tolerance developed to the effects of PG01037 treatment on cocaine choice, tolerance did not develop to the disruptive effects on food-maintained responding. These findings suggest that combination treatments that decrease cocaine-induced elevations in DA may enhance the efficacy of D3R antagonists on cocaine self-administration.
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Affiliation(s)
- William S John
- Department of Physiology and Pharmacology, Wake Forest School of Medicine, Winston-Salem, NC, USA.
| | - Amy Hauck Newman
- Medicinal Chemistry Section, Molecular Targets and Medications Discovery Branch, National Institute on Drug Abuse - Intramural Research Program, National Institutes of Health, Baltimore, MD, USA.
| | - Michael A Nader
- Department of Physiology and Pharmacology, Wake Forest School of Medicine, Winston-Salem, NC, USA.
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Czoty PW, Nader MA. Effects of oral and intravenous administration of buspirone on food-cocaine choice in socially housed male cynomolgus monkeys. Neuropsychopharmacology 2015; 40:1072-83. [PMID: 25393717 PMCID: PMC4367460 DOI: 10.1038/npp.2014.300] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/14/2014] [Revised: 10/31/2014] [Accepted: 11/03/2014] [Indexed: 01/05/2023]
Abstract
Drugs acting at D3 dopamine receptors have been suggested as medications for cocaine dependence. These experiments examined the effects of intravenously and orally administered buspirone, a D2-like receptor antagonist with high affinity for D3 and D4 receptors, on the relative reinforcing strength of cocaine in group-housed male cynomolgus monkeys. Use of socially housed monkeys permitted the assessment of whether social status, known to influence D2-like receptor availability, modulates the behavioral effects of buspirone. Buspirone was administered acutely to monkeys self-administering cocaine under a food-drug choice procedure in which a cocaine self-administration dose-effect curve was determined daily. When administered by either route, buspirone significantly decreased cocaine choice in dominant-ranked monkeys. In subordinate monkeys, however, i.v. buspirone was ineffective on average, and oral buspirone increased choice of lower cocaine doses. The effects of buspirone only differed according to route of administration in subordinate monkeys. Moreover, it is noteworthy that the effects of buspirone were similar to those of the D3 receptor-selective antagonist PG01037 and qualitatively different than those of less selective drugs that act at D2-like or serotonin (5-HT)1A receptors, suggesting a D3 and possibly D4 receptor mechanism of action for buspirone. Taken together, the data support the utility of drugs targeting D3/D4 receptors as potential treatments for cocaine addiction, particularly in combination with enriching environmental manipulations.
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Affiliation(s)
- Paul W Czoty
- Departments of Physiology and Pharmacology, Wake Forest University School of Medicine, Winston-Salem, NC, USA
| | - Michael A Nader
- Departments of Physiology and Pharmacology, Wake Forest University School of Medicine, Winston-Salem, NC, USA,Department Radiology, Wake Forest University School of Medicine, Winston-Salem, NC, USA,Department of Physiology and Pharmacology, Wake Forest University School of Medicine, Medical Center Boulevard, Winston-Salem, NC 27157-1083, USA, Tel: +1 336 713 7172, Fax: +1 336 713 7180, E-mail:
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John WS, Banala AK, Newman AH, Nader MA. Effects of buspirone and the dopamine D3 receptor compound PG619 on cocaine and methamphetamine self-administration in rhesus monkeys using a food-drug choice paradigm. Psychopharmacology (Berl) 2015; 232:1279-89. [PMID: 25327444 PMCID: PMC4754084 DOI: 10.1007/s00213-014-3760-6] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/27/2014] [Accepted: 09/25/2014] [Indexed: 12/30/2022]
Abstract
RATIONALE The dopamine (DA) D2 and D3 receptors have been associated with cocaine abuse. A recent study with the D3 receptor (D3R) partial agonist PG619 found that it attenuated cocaine-induced reinstatement and the D2-like receptor antagonist buspirone has shown positive outcomes in two studies of cocaine abuse in monkeys. However, a recent clinical trial indicated that buspirone did not improve abstinence in treatment-seeking cocaine abusers. OBJECTIVE The objective of the study was to examine PG619 and buspirone under a food-drug choice paradigm in order to better model the clinical findings. In addition, we extended the characterization of both compounds to include methamphetamine (MA) self-administration (SA). METHODS Six adult male rhesus monkeys were trained to respond under a concurrent food (1.0-g pellets) and drug (0.01-0.3 mg/kg/injection cocaine or MA) choice paradigm in which complete SA dose-response curves were determined each session (N = 3/group). Monkeys received 5 days of treatment with either PG619 (0.1-3.0 mg/kg, i.v.) or buspirone (0.01-1.0 mg/kg, i.m.). In a follow-up study, the SA doses were reduced (0.003-0.1 mg/kg/injection) to increase reinforcement frequency and buspirone was retested. RESULTS PG619 did not affect cocaine or MA choice, while buspirone increased low-dose cocaine choice. Changing the SA doses increased the number of reinforcers received each session, but buspirone did not decrease drug choice. CONCLUSIONS Consistent with clinical findings, these results do not support the use of buspirone for psychostimulant abuse and suggest that food-drug choice paradigms may have greater predictive validity than the use of other schedules of reinforcement.
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Affiliation(s)
- William S. John
- Department of Physiology and Pharmacology, Wake Forest, University School of Medicine, Medical Center Boulevard, Winston-Salem, NC 27157-1083, USA
| | - Ashwini K. Banala
- Medicinal Chemistry Section, Molecular Targets and Medications, Discovery Branch, National Institute on Drug Abuse-Intramural, Research Program, National Institutes of Health, Baltimore, MD, USA
| | - Amy H. Newman
- Medicinal Chemistry Section, Molecular Targets and Medications, Discovery Branch, National Institute on Drug Abuse-Intramural, Research Program, National Institutes of Health, Baltimore, MD, USA
| | - Michael A. Nader
- Department of Physiology and Pharmacology, Wake Forest, University School of Medicine, Medical Center Boulevard, Winston-Salem, NC 27157-1083, USA
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Keck TM, John WS, Czoty PW, Nader MA, Newman AH. Identifying Medication Targets for Psychostimulant Addiction: Unraveling the Dopamine D3 Receptor Hypothesis. J Med Chem 2015; 58:5361-80. [PMID: 25826710 PMCID: PMC4516313 DOI: 10.1021/jm501512b] [Citation(s) in RCA: 88] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The dopamine D3 receptor (D3R) is a target for developing medications to treat substance use disorders. D3R-selective compounds with high affinity and varying efficacies have been discovered, providing critical research tools for cell-based studies that have been translated to in vivo models of drug abuse. D3R antagonists and partial agonists have shown especially promising results in rodent models of relapse-like behavior, including stress-, drug-, and cue-induced reinstatement of drug seeking. However, to date, translation to human studies has been limited. Herein, we present an overview and illustrate some of the pitfalls and challenges of developing novel D3R-selective compounds toward clinical utility, especially for treatment of cocaine abuse. Future research and development of D3R-selective antagonists and partial agonists for substance abuse remains critically important but will also require further evaluation and development of translational animal models to determine the best time in the addiction cycle to target D3Rs for optimal therapeutic efficacy.
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Affiliation(s)
- Thomas M Keck
- †Medicinal Chemistry Section, Molecular Targets and Medications Discovery Branch, National Institute on Drug Abuse-Intramural Research Program, National Institutes of Health, 333 Cassell Drive, Baltimore, Maryland 21224, United States
| | - William S John
- §Department of Physiology and Pharmacology, Wake Forest School of Medicine, Winston-Salem, North Carolina 27157-1083, United States
| | - Paul W Czoty
- §Department of Physiology and Pharmacology, Wake Forest School of Medicine, Winston-Salem, North Carolina 27157-1083, United States
| | - Michael A Nader
- §Department of Physiology and Pharmacology, Wake Forest School of Medicine, Winston-Salem, North Carolina 27157-1083, United States
| | - Amy Hauck Newman
- †Medicinal Chemistry Section, Molecular Targets and Medications Discovery Branch, National Institute on Drug Abuse-Intramural Research Program, National Institutes of Health, 333 Cassell Drive, Baltimore, Maryland 21224, United States
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Blum K, Febo M, Thanos PK, Baron D, Fratantonio J, Gold M. Clinically Combating Reward Deficiency Syndrome (RDS) with Dopamine Agonist Therapy as a Paradigm Shift: Dopamine for Dinner? Mol Neurobiol 2015; 52:1862-1869. [PMID: 25750061 PMCID: PMC4586005 DOI: 10.1007/s12035-015-9110-9] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2014] [Accepted: 01/21/2015] [Indexed: 01/23/2023]
Abstract
Everyday, there are several millions of people that are increasingly unable to combat their frustrating and even fatal romance with getting high and/or experiencing “normal” feelings of well-being. In the USA, the FDA has approved pharmaceuticals for drug and alcohol abuse: tobacco and nicotine replacement therapy. The National Institute on Drug Abuse (NIDA) and the National Institute on Alcohol Abuse and Alcoholism (NIAAA) remarkably continue to provide an increasing understanding of the intricate functions of brain reward circuitry through sophisticated neuroimaging and molecular genetic applied technology. Similar work is intensely investigated on a worldwide basis with enhanced clarity and increased interaction between not only individual scientists but across many disciplines. However, while it is universally agreed that dopamine is a major neurotransmitter in terms of reward dependence, there remains controversy regarding how to modulate its role clinically to treat and prevent relapse for both substance and non-substance-related addictive behaviors. While the existing FDA-approved medications promote blocking dopamine, we argue that a more prudent paradigm shift should be biphasic—short-term blockade and long-term upregulation, enhancing functional connectivity of brain reward circuits.
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Affiliation(s)
- Kenneth Blum
- Department of Psychiatry and McKnight Brain Institute, College of Medicine, University of Florida, P. O. Box 100256, Gainesville, FL 32610-0256 USA
- Human Integrated Services Unit, Center for Clinical and Translational Science, Department of Psychiatry, College of Medicine, University of Vermont, Burlington, VT USA
- Division of Applied Clinical Research, Dominion Diagnostics, LLC, North Kingstown, RI USA
- Department of Addiction Research and Therapy, Malibu Beach Recovery Center, Malibu, CA USA
| | - Marcelo Febo
- Department of Psychiatry and McKnight Brain Institute, College of Medicine, University of Florida, P. O. Box 100256, Gainesville, FL 32610-0256 USA
| | - Panayotis K. Thanos
- Behavior Neuropharmacology and Neuroimaging Laboratory, Department of Psychology, SUNY at Stony Brook, Stony Brook, NY USA
| | - David Baron
- Department of Psychiatry, Keck School of Medicine, University of Southern California, Los Angeles, CA USA
- Keck School of Medicine, University of Southern California, Los Angeles, CA USA
| | - James Fratantonio
- Division of Applied Clinical Research, Dominion Diagnostics, LLC, North Kingstown, RI USA
| | - Mark Gold
- Department of Psychiatry and McKnight Brain Institute, College of Medicine, University of Florida, P. O. Box 100256, Gainesville, FL 32610-0256 USA
- Department of Research, Rivermernd Health, Atlanta, GA USA
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Banks ML, Hutsell BA, Blough BE, Poklis JL, Negus SS. Preclinical Assessment of Lisdexamfetamine as an Agonist Medication Candidate for Cocaine Addiction: Effects in Rhesus Monkeys Trained to Discriminate Cocaine or to Self-Administer Cocaine in a Cocaine Versus Food Choice Procedure. Int J Neuropsychopharmacol 2015; 18:pyv009. [PMID: 25618405 PMCID: PMC4458439 DOI: 10.1093/ijnp/pyv009] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/10/2014] [Accepted: 01/20/2015] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND Chronic amphetamine treatment decreases cocaine consumption in preclinical and human laboratory studies and in clinical trials. Lisdexamfetamine is an amphetamine prodrug in which L-lysine is conjugated to the terminal nitrogen of d-amphetamine. Prodrugs may be advantageous relative to their active metabolites due to slower onsets and longer durations of action; however, lisdexamfetamine treatment's efficacy in decreasing cocaine consumption is unknown. METHODS This study compared lisdexamfetamine and d-amphetamine effects in rhesus monkeys using two behavioral procedures: (1) a cocaine discrimination procedure (training dose = 0.32mg/kg cocaine, i.m.); and (2) a cocaine-versus-food choice self-administration procedure. RESULTS In the cocaine-discrimination procedure, lisdexamfetamine (0.32-3.2mg/kg, i.m.) substituted for cocaine with lower potency, slower onset, and longer duration of action than d-amphetamine (0.032-0.32mg/kg, i.m.). Consistent with the function of lisdexamfetamine as an inactive prodrug for amphetamine, the time course of lisdexamfetamine effects was related to d-amphetamine plasma levels by a counter-clockwise hysteresis loop. In the choice procedure, cocaine (0-0.1mg/kg/injection, i.v.) and food (1g banana-flavored pellets) were concurrently available, and cocaine maintained a dose-dependent increase in cocaine choice under baseline conditions. Treatment for 7 consecutive days with lisdexamfetamine (0.32-3.2mg/kg/day, i.m.) or d-amphetamine (0.032-0.1mg/kg/h, i.v.) produced similar dose-dependent rightward shifts in cocaine dose-effect curves and decreases in preference for 0.032mg/kg/injection cocaine. CONCLUSIONS Lisdexamfetamine has a slower onset and longer duration of action than amphetamine but retains amphetamine's efficacy to reduce the choice of cocaine in rhesus monkeys. These results support further consideration of lisdexamfetamine as an agonist-based medication candidate for cocaine addiction.
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Affiliation(s)
- Matthew L Banks
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, VA (Drs Banks, Hutsell, Negus, and Mr Poklis); Institute for Drug and Alcohol Studies, Virginia Commonwealth University, Richmond, VA (Drs Banks and Negus); Center for Drug Discovery, Research Triangle Institute, Research Triangle Park, NC (Dr Blough)
| | - Blake A Hutsell
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, VA (Drs Banks, Hutsell, Negus, and Mr Poklis); Institute for Drug and Alcohol Studies, Virginia Commonwealth University, Richmond, VA (Drs Banks and Negus); Center for Drug Discovery, Research Triangle Institute, Research Triangle Park, NC (Dr Blough)
| | - Bruce E Blough
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, VA (Drs Banks, Hutsell, Negus, and Mr Poklis); Institute for Drug and Alcohol Studies, Virginia Commonwealth University, Richmond, VA (Drs Banks and Negus); Center for Drug Discovery, Research Triangle Institute, Research Triangle Park, NC (Dr Blough)
| | - Justin L Poklis
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, VA (Drs Banks, Hutsell, Negus, and Mr Poklis); Institute for Drug and Alcohol Studies, Virginia Commonwealth University, Richmond, VA (Drs Banks and Negus); Center for Drug Discovery, Research Triangle Institute, Research Triangle Park, NC (Dr Blough)
| | - S Stevens Negus
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, VA (Drs Banks, Hutsell, Negus, and Mr Poklis); Institute for Drug and Alcohol Studies, Virginia Commonwealth University, Richmond, VA (Drs Banks and Negus); Center for Drug Discovery, Research Triangle Institute, Research Triangle Park, NC (Dr Blough)
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Performance on a strategy set shifting task in rats following adult or adolescent cocaine exposure. Psychopharmacology (Berl) 2014; 231:4489-501. [PMID: 24800898 PMCID: PMC4224606 DOI: 10.1007/s00213-014-3598-y] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/05/2013] [Accepted: 04/14/2014] [Indexed: 10/25/2022]
Abstract
RATIONALE Neuropsychological testing is widespread in adult cocaine abusers, but lacking in teens. Animal models may provide insight into age-related neuropsychological consequences of cocaine exposure. OBJECTIVES The objective of the present study is to determine whether developmental plasticity protects or hinders behavioral flexibility after cocaine exposure in adolescent vs. adult rats. METHODS Using a yoked-triad design, one rat controlled cocaine delivery and the other two passively received cocaine or saline. Rats controlling cocaine delivery (1.0 mg/kg) self-administered for 18 sessions (starting P37 or P77), followed by 18 drug-free days. Rats next were tested in a strategy set shifting task, lasting 11-13 sessions. RESULTS Cocaine self-administration did not differ between age groups. During initial set formation, adolescent-onset groups required more trials to reach criterion and made more errors than adult-onset groups. During the set shift phase, rats with adult-onset cocaine self-administration experience had higher proportions of correct trials and fewer perseverative + regressive errors than age-matched yoked-controls or rats with adolescent-onset cocaine self-administration experience. During reversal learning, rats with adult-onset cocaine experience (self-administered or passive) required fewer trials to reach criterion, and the self-administering rats made fewer perseverative + regressive errors than yoked-saline rats. Rats receiving adolescent-onset yoked-cocaine had more trial omissions and longer lever press reaction times than age-matched rats self-administering cocaine or receiving yoked-saline. CONCLUSIONS Prior cocaine self-administration may impair memory to reduce proactive interference during set shifting and reversal learning in adult-onset but not adolescent-onset rats (developmental plasticity protective). Passive cocaine may disrupt aspects of executive function in adolescent-onset but not adult-onset rats (developmental plasticity hinders).
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Nader MA, Balster RL, Henningfield JE. William L. Woolverton: a case history in unraveling the behavioral pharmacology of stimulants. Neuropharmacology 2014; 87:4-8. [PMID: 24859612 DOI: 10.1016/j.neuropharm.2014.05.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2014] [Revised: 05/01/2014] [Accepted: 05/06/2014] [Indexed: 11/25/2022]
Abstract
Clinical findings suggest that the most promising strategy for cocaine addiction is a combination of indirect-acting monoamine agonists with some form of behavioral intervention. This approach can be traced back to preclinical research, some of which was conducted by William L. Woolverton. The goal of this brief review is to provide readers with an appreciation for the experimental breadth involving both behavior and pharmacology that encompassed Woolverton's amazing career, from the evaluation of abuse liability of drugs to the use of complex behavioral contingencies to better model the human condition. We begin with Woolverton's research using simple and complex schedules of reinforcement to evaluate abuse liability and how that has impacted current animal models. We also discuss his use of cocaine vs. food choice schedules of reinforcement as a model to evaluate potential medications for treating cocaine use disorders. Woolverton concluded that drug taking behavior was not "impulsive" and "out of control" as has often been proposed, but rather directly determined by the environmental contingencies and the context of its availability, providing a nuanced understanding of drug-behavior interactions. This article is part of the Special Issue entitled 'CNS Stimulants'
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Affiliation(s)
- Michael A Nader
- Department of Physiology and Pharmacology, Wake Forest School of Medicine, Winston-Salem, NC, USA.
| | - Robert L Balster
- Department of Pharmacology and Toxicology, School of Medicine, Virginia Commonwealth University, Richmond, VA, USA
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Nader MA, Banks ML. Environmental modulation of drug taking: Nonhuman primate models of cocaine abuse and PET neuroimaging. Neuropharmacology 2014; 76 Pt B:510-7. [PMID: 23748095 PMCID: PMC3812308 DOI: 10.1016/j.neuropharm.2013.05.044] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2013] [Revised: 05/06/2013] [Accepted: 05/15/2013] [Indexed: 11/27/2022]
Abstract
The current review highlights the importance of environmental variables on cocaine self-administration in nonhuman primate models of drug abuse. In addition to describing the behavioral consequences, potential mechanisms of action are discussed, based on imaging results using the non-invasive and translational technique of positron emission tomography (PET). In this review, the role of three environmental variables - both positive and negative - are described: alternative non-drug reinforcers; social rank (as an independent variable) and punishment of cocaine self-administration. These environmental stimuli can profoundly influence brain function and drug self-administration. We focus on environmental manipulations involving non-drug alternatives (e.g., food reinforcement) using choice paradigms. Manipulations such as response cost and social variables (e.g., social rank, social stress) also influence the behavioral effects of drugs. Importantly, these manipulations are amenable to brain imaging studies. Taken together, these studies emphasize the profound impact environmental variables can have on drug taking, which should provide important information related to individual-subject variability in treatment responsiveness, and the imaging work may highlight pharmacological targets for medications related to treating drug abuse. This article is part of a Special Issue entitled 'NIDA 40th Anniversary Issue'.
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Affiliation(s)
- Michael A Nader
- Department of Physiology and Pharmacology, Wake Forest University School of Medicine, Medical Center Blvd., 546 NRC, Winston-Salem, NC 27157-1083, USA.
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Banks ML, Blough BE, Fennell TR, Snyder RW, Negus SS. Effects of phendimetrazine treatment on cocaine vs food choice and extended-access cocaine consumption in rhesus monkeys. Neuropsychopharmacology 2013; 38:2698-707. [PMID: 23893022 PMCID: PMC3828541 DOI: 10.1038/npp.2013.180] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/15/2013] [Revised: 07/23/2013] [Accepted: 07/24/2013] [Indexed: 01/25/2023]
Abstract
There is currently no Food and Drug Administration-approved pharmacotherapy for cocaine addiction. Monoamine releasers such as d-amphetamine constitute one class of candidate medications, but clinical use and acceptance are hindered by their own high-abuse liability. Phendimetrazine (PDM) is a schedule III anorectic agent that functions as both a low-potency monoamine-uptake inhibitor and as a prodrug for the monoamine-releaser phenmetrazine (PM), and it may serve as a clinically available, effective, and safer alternative to d-amphetamine. This study determined efficacy of chronic PDM to reduce cocaine self-administration by rhesus monkeys (N=4) using a novel procedure that featured both daily assessments of cocaine vs food choice (to assess medication efficacy to reallocate behavior away from cocaine choice and toward choice of an alternative reinforcer) and 20 h/day cocaine access (to allow high-cocaine intake). Continuous 21-day treatment with ramping PDM doses (days 1-7: 0.32 mg/kg/h; days 8-21: 1.0 mg/kg/h) reduced cocaine choices, increased food choices, and nearly eliminated extended-access cocaine self-administration without affecting body weight. There was a trend for plasma PDM and PM levels to correlate with efficacy to decrease cocaine choice such that the monkey with the highest plasma PDM and PM levels also demonstrated the greatest reductions in cocaine choice. These results support further consideration of PDM as a candidate anti-cocaine addiction pharmacotherapy. Moreover, PDM may represent a novel pharmacotherapeutic approach for cocaine addiction because it may simultaneously function as both a monoamine-uptake inhibitor (via the parent drug PDM) and as a monoamine releaser (via the active metabolite PM).
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Affiliation(s)
- Matthew L Banks
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, VA, USA,Institute for Drug and Alcohol Studies, Virginia Commonwealth University, Richmond, VA, USA,Department of Pharmacology and Toxicology, Virginia Commonwealth University, 410 North 12th Street, PO Box 980613, Richmond, VA 23298, USA, Tel: +1 804 828 8466, Fax: +1 804 828 2117, E-mail:
| | - Bruce E Blough
- Center for Organic and Medicinal Chemistry, Research Triangle Institute International, Research Triangle Park, NC, USA
| | - Timothy R Fennell
- Department of Pharmacology and Toxicology, Research Triangle Institute International, Research Triangle Park, NC, USA
| | - Rodney W Snyder
- Department of Pharmacology and Toxicology, Research Triangle Institute International, Research Triangle Park, NC, USA
| | - S Stevens Negus
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, VA, USA,Institute for Drug and Alcohol Studies, Virginia Commonwealth University, Richmond, VA, USA
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Czoty PW, Gage HD, Garg PK, Garg S, Nader MA. Effects of repeated treatment with the dopamine D2/D3 receptor partial agonist aripiprazole on striatal D2/D3 receptor availability in monkeys. Psychopharmacology (Berl) 2013; 231:10.1007/s00213-013-3274-7. [PMID: 24077804 PMCID: PMC3969775 DOI: 10.1007/s00213-013-3274-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/19/2012] [Accepted: 08/29/2013] [Indexed: 01/11/2023]
Abstract
RATIONALE Chronic treatment with dopamine (DA) receptor agonists and antagonists can differentially affect measures of DA D2/D3 receptor number and function, but the effects of chronic treatment with a partial D2/D3 receptor agonist are not clear. OBJECTIVE We used a within-subjects design in male cynomolgus monkeys to determine the effects of repeated (17-day) treatment with the D2/D3 receptor partial agonist aripiprazole (ARI; 0.03 mg/kg and 0.1 mg/kg i.m.) on food-reinforced behavior (n = 5) and on D2/D3 receptor availability as measured with positron emission tomography (PET; n = 9). METHODS Five monkeys responded under a fixed-ratio 50 schedule of food reinforcement and D2/D3 receptor availability was measured before and 4 days after ARI treatment using PET and the D2/D3 receptor-selective radioligand [18F]fluoroclebopride (FCP). Four additional monkeys were studied using [11C]raclopride and treated sequentially with each dose of ARI for 17 days. RESULTS ARI decreased food-maintained responding with minimal evidence of tolerance. Repeated ARI administration increased FCP and raclopride distribution volume ratios (DVRs) in the caudate nucleus and putamen in most monkeys, but decreases were observed in monkeys with the highest baseline DVRs. CONCLUSIONS The results indicate that repeated treatment with a low-efficacy DA receptor partial agonist produces effects on brain D2/D3 receptor availability that are qualitatively different from those of both high-efficacy receptor agonists and antagonists, and suggest that the observed individual differences in response to ARI treatment may reflect its partial agonist activity.
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Affiliation(s)
- Paul W. Czoty
- Department of Physiology and Pharmacology, Wake Forest University School of Medicine, Winston-Salem, NC 27157-1083
| | - H. Donald Gage
- Department of Radiology, Wake Forest University School of Medicine, Winston-Salem, NC 27157-1083
| | - Pradeep K. Garg
- Department of Radiology, Wake Forest University School of Medicine, Winston-Salem, NC 27157-1083
| | - Sudha Garg
- Department of Radiology, Wake Forest University School of Medicine, Winston-Salem, NC 27157-1083
| | - Michael A. Nader
- Department of Physiology and Pharmacology, Wake Forest University School of Medicine, Winston-Salem, NC 27157-1083
- Department of Radiology, Wake Forest University School of Medicine, Winston-Salem, NC 27157-1083
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Neisewander JL, Cheung THC, Pentkowski NS. Dopamine D3 and 5-HT1B receptor dysregulation as a result of psychostimulant intake and forced abstinence: Implications for medications development. Neuropharmacology 2013; 76 Pt B:301-19. [PMID: 23973315 DOI: 10.1016/j.neuropharm.2013.08.014] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2013] [Revised: 07/24/2013] [Accepted: 08/05/2013] [Indexed: 10/26/2022]
Abstract
Addiction to psychostimulants, including cocaine and amphetamine, is associated with dysregulation of dopamine and serotonin (5-HT) neurotransmitter systems. Neuroadaptations in these systems vary depending on the stage of the drug taking-abstinence-relapse cycle. Consequently, the effects of potential treatments that target these systems may vary depending on whether they are given during abstinence or relapse. In this review, we discuss evidence that dopamine D3 receptors (D3Rs) and 5-HT1B receptors (5-HT1BRs) are dysregulated in response to both chronic psychostimulant use and subsequent abstinence. We then review findings from preclinical self-administration models which support targeting D3Rs and 5-HT1BRs as potential medications for psychostimulant dependence. Potential side effects of the treatments are discussed and attention is given to studies reporting positive treatment outcomes that depend on: 1) whether testing occurs during self-administration versus abstinence, 2) whether escalation of drug self-administration has occurred, 3) whether the treatments are given repeatedly, and 4) whether social factors influence treatment outcomes. We conclude that D3/D2 agonists may decrease psychostimulant intake; however, side effects of D3/D2R full agonists may limit their therapeutic potential, whereas D3/D2R partial agonists have fewer undesirable side effects. D3-selective antagonists may not reduce psychostimulant intake during relapse, but nonetheless, may decrease motivation for seeking psychostimulants with relatively few side-effects. 5-HT1BR agonists provide a striking example of treatment outcomes that are dependent on the stage of the addiction cycle. Specifically, these agonists initially increase cocaine's reinforcing effects during maintenance of self-administration, but after a period of abstinence they reduce psychostimulant seeking and the resumption of self-administration. In conclusion, we suggest that factors contributing to dysregulation of monoamine systems, including drug history, abstinence, and social context, should be considered when evaluating potential treatments to better model treatment effects in humans. This article is part of a Special Issue entitled 'NIDA 40th Anniversary Issue'.
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Affiliation(s)
- Janet L Neisewander
- School of Life Sciences, P.O. Box 874501, Arizona State University, Tempe, AZ 85287-4501, USA.
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Effects of 14-day treatment with the schedule III anorectic phendimetrazine on choice between cocaine and food in rhesus monkeys. Drug Alcohol Depend 2013; 131:204-13. [PMID: 23726979 PMCID: PMC3713102 DOI: 10.1016/j.drugalcdep.2013.05.005] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/19/2012] [Revised: 04/22/2013] [Accepted: 05/02/2013] [Indexed: 12/25/2022]
Abstract
BACKGROUND The clinical utility of monoamine releasers such as phenmetrazine or d-amphetamine as candidate agonist medications for cocaine dependence is hindered by their high abuse liability. Phendimetrazine is a clinically available schedule III anorectic that functions as a prodrug for phenmetrazine and thus may have lower abuse liability. This study determined the effects of continuous 14-day treatment with phendimetrazine on cocaine vs. food choice in rhesus monkeys (N=4). METHODS Responding was maintained under a concurrent schedule of food delivery (1-g pellets, fixed-ratio 100 schedule) and cocaine injections (0-0.1mg/kg/injection, fixed-ratio 10 schedule). Cocaine choice dose-effect curves were determined daily before and during 14-day periods of continuous intravenous treatment with saline or (+)-phendimetrazine (0.32-1.0mg/kg/h). Effects of 14-day treatment with (+)-phenmetrazine (0.1-0.32 mg/kg/h; N=5) and d-amphetamine (0.032-0.1mg/kg/h; N=6) were also examined for comparison. RESULTS During saline treatment, food was primarily chosen during availability of low cocaine doses (0, 0.0032, and 0.01 mg/kg/injection), and cocaine was primarily chosen during availability of higher cocaine doses (0.032 and 0.1mg/kg/injection). Phendimetrazine initially decreased overall responding without significantly altering cocaine choice. Over the course of 14 days, tolerance developed to rate decreasing effects, and phendimetrazine dose-dependently decreased cocaine choice (significant at 0.032 mg/kg/injection cocaine). Phenmetrazine and d-amphetamine produced qualitatively similar effects. CONCLUSIONS These results demonstrate that phendimetrazine can produce significant, though modest, reductions in cocaine choice in rhesus monkeys. Phendimetrazine may be especially suitable as a candidate medication for human studies because of its schedule III clinical availability.
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