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D'Souza MS, Markou A. The "stop" and "go" of nicotine dependence: role of GABA and glutamate. Cold Spring Harb Perspect Med 2013; 3:3/6/a012146. [PMID: 23732855 DOI: 10.1101/cshperspect.a012146] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Nicotine plays an important role in the initiation and maintenance of tobacco smoking. Importantly, chronic nicotine exposure alters the function of brain reward systems, resulting in the development of a nicotine-dependent state. This nicotine-dependent state is associated with aversive affective and somatic signs upon abstinence from smoking, often leading to relapse in abstinent smokers. This article reviews the role of the major excitatory and inhibitory neurotransmitters glutamate and γ-aminobutyric acid (GABA), respectively, in both the reinforcing effects of nicotine and development of nicotine dependence. Evidence suggests that blockade of glutamatergic neurotransmission attenuates both nicotine intake and nicotine seeking. In contrast, both nicotine intake and nicotine seeking are attenuated when GABA neurotransmission is facilitated. In conclusion, medications that either attenuate/negatively modulate glutamatergic neurotransmission or facilitate/positively modulate GABA neurotransmission may be useful for promoting smoking cessation in humans.
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Affiliation(s)
- Manoranjan S D'Souza
- Department of Psychiatry, School of Medicine, University of California San Diego, La Jolla, California 92093, USA
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52
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Zotti M, Colaianna M, Morgese MG, Tucci P, Schiavone S, Avato P, Trabace L. Carvacrol: from ancient flavoring to neuromodulatory agent. Molecules 2013; 18:6161-72. [PMID: 23708230 PMCID: PMC6270539 DOI: 10.3390/molecules18066161] [Citation(s) in RCA: 82] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2013] [Revised: 05/08/2013] [Accepted: 05/20/2013] [Indexed: 11/16/2022] Open
Abstract
Oregano and thyme essential oils are used for therapeutic, aromatic and gastronomic purposes due to their richness in active substances, like carvacrol; however, the effects of the latter on the central nervous system have been poorly investigated. The aim of our study was to define the effects of carvacrol on brain neurochemistry and behavioural outcome in rats. Biogenic amine content in the prefrontal cortex and hippocampus after chronic or acute oral carvacrol administration was measured. Animals were assessed by a forced swimming test. Carvacrol, administered for seven consecutive days (12.5 mg/kg p.o.), was able to increase dopamine and serotonin levels in the prefrontal cortex and hippocampus. When single doses were used (150 and 450 mg/kg p.o.), dopamine content was increased in the prefrontal cortex at both dose levels. On the contrary, a significant dopamine reduction in hippocampus of animals treated with 450 mg/kg of carvacrol was found. Acute carvacrol administration only significantly reduced serotonin content in either the prefrontal cortex or in the hippocampus at the highest dose. Moreover, acute carvacrol was ineffective in producing changes in the forced swimming test. Our data suggest that carvacrol is a brain-active molecule that clearly influences neuronal activity through modulation of neurotransmitters. If regularly ingested in low concentrations, it might determine feelings of well-being and could possibly have positive reinforcer effects.
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Affiliation(s)
- Margherita Zotti
- Department of Clinical and Experimental Medicine, University of Foggia, Foggia 71121, Italy; E-Mails: (M.Z.); (M.C.); (M.G.M.); (P.T.)
| | - Marilena Colaianna
- Department of Clinical and Experimental Medicine, University of Foggia, Foggia 71121, Italy; E-Mails: (M.Z.); (M.C.); (M.G.M.); (P.T.)
- Department of Pathology and Immunology, University of Geneva, Geneva 1211, Switzerland
| | - Maria Grazia Morgese
- Department of Clinical and Experimental Medicine, University of Foggia, Foggia 71121, Italy; E-Mails: (M.Z.); (M.C.); (M.G.M.); (P.T.)
| | - Paolo Tucci
- Department of Clinical and Experimental Medicine, University of Foggia, Foggia 71121, Italy; E-Mails: (M.Z.); (M.C.); (M.G.M.); (P.T.)
| | - Stefania Schiavone
- Department of Mental Health and Psychiatry, Geneva University Hospital and University of Geneva, Geneva 1211, Switzerland; E-Mail:
| | - Pinarosa Avato
- Department of Pharmacy-Drug Sciences, University of Bari, “A. Moro”, Bari 70125, Italy; E-Mail:
| | - Luigia Trabace
- Department of Clinical and Experimental Medicine, University of Foggia, Foggia 71121, Italy; E-Mails: (M.Z.); (M.C.); (M.G.M.); (P.T.)
- Author to whom correspondence should be addressed; E-Mail: ; Tel.: +39-0881-588056; Fax: +39-0881-588037
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Davis C. From passive overeating to "food addiction": a spectrum of compulsion and severity. ISRN OBESITY 2013; 2013:435027. [PMID: 24555143 PMCID: PMC3901973 DOI: 10.1155/2013/435027] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/20/2013] [Accepted: 04/16/2013] [Indexed: 01/17/2023]
Abstract
A psychobiological dimension of eating behaviour is proposed, which is anchored at the low end by energy intake that is relatively well matched to energy output and is reflected by a stable body mass index (BMI) in the healthy range. Further along the continuum are increasing degrees of overeating (and BMI) characterized by more severe and more compulsive ingestive behaviours. In light of the many similarities between chronic binge eating and drug abuse, several authorities have adopted the perspective that an apparent dependence on highly palatable food-accompanied by emotional and social distress-can be best conceptualized as an addiction disorder. Therefore, this review also considers the overlapping symptoms and characteristics of binge eating disorder (BED) and models of food addiction, both in preclinical animal studies and in human research. It also presents this work in the context of the modern and "toxic" food environment and therein the ubiquitous triggers for over-consumption. We complete the review by providing evidence that what we have come to call "food addiction" may simply be a more acute and pathologically dense form of BED.
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Affiliation(s)
- Caroline Davis
- Kinesiology & Health Sciences, Faculty of Health, York University, 343 Bethune College, 4700 Keele Street, Toronto, ON, Canada M3J 1P3
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Cummins E, Leri F. Animal studies trigger new insights on the use of methadone maintenance. Expert Opin Drug Discov 2013; 4:577-86. [PMID: 23485087 DOI: 10.1517/17460440902915533] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
BACKGROUND Although steady-state methadone (SSM) treatment is mainly used for opioid addiction, some clinical studies indicate that it also reduces cocaine abuse in opioid-dependent individuals. OBJECTIVE/METHODS To present evidence suggesting that SSM may be useful in the treatment of cocaine addiction without pre-existing opioid dependence. We review studies in animals investigating the effects of SSM on behaviors motivated by cocaine and on cocaine-induced alterations of genes expression in the rat brain. CONCLUSION SSM reduces cocaine intake, blocks cocaine seeking and normalizes expression of genes known to regulate cocaine seeking. These findings suggest that SSM could be an effective pharmacological agent to assist cocaine detoxification and prevention of relapse to cocaine abuse in individuals not co-dependent on opioid.
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Affiliation(s)
- Erin Cummins
- PhD Student University of Guelph, Department of Psychology, Guelph (ON), N1G 2W1, Canada
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Lee G, Kikuno K, Bahn JH, Kim KM, Park JH. Dopamine D2 Receptor as a Cellular Component Controlling Nocturnal Hyperactivities inDrosophila melanogaster. Chronobiol Int 2013; 30:443-59. [DOI: 10.3109/07420528.2012.741169] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Piazza PV, Deroche-Gamonet V. A multistep general theory of transition to addiction. Psychopharmacology (Berl) 2013; 229:387-413. [PMID: 23963530 PMCID: PMC3767888 DOI: 10.1007/s00213-013-3224-4] [Citation(s) in RCA: 146] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/23/2013] [Accepted: 07/21/2013] [Indexed: 12/20/2022]
Abstract
BACKGROUND Several theories propose alternative explanations for drug addiction. OBJECTIVES We propose a general theory of transition to addiction that synthesizes knowledge generated in the field of addiction into a unitary explanatory frame. MAJOR PRINCIPLES OF THE THEORY Transition to addiction results from a sequential three-step interaction between: (1) individual vulnerability; (2) degree/amount of drug exposure. The first step, sporadic recreational drug use is a learning process mediated by overactivation of neurobiological substrates of natural rewards that allows most individuals to perceive drugs as highly rewarding stimuli. The second, intensified, sustained, escalated drug use occurs in some vulnerable individuals who have a hyperactive dopaminergic system and impaired prefrontal cortex function. Sustained and prolonged drug use induces incentive sensitization and an allostatic state that makes drugs strongly wanted and needed. Habit formation can also contribute to stabilizing sustained drug use. The last step, loss of control of drug intake and full addiction, is due to a second vulnerable phenotype. This loss-of-control-prone phenotype is triggered by long-term drug exposure and characterized by long-lasting loss of synaptic plasticity in reward areas in the brain that induce a form of behavioral crystallization resulting in loss of control of drug intake. Because of behavioral crystallization, drugs are now not only wanted and needed but also pathologically mourned when absent. CONCLUSIONS This general theory demonstrates that drug addiction is a true psychiatric disease caused by a three-step interaction between vulnerable individuals and amount/duration of drug exposure.
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Affiliation(s)
- Pier Vincenzo Piazza
- Neurocentre Magendie, Physiopathologie de la Plasticité Neuronale, U862, INSERM, 146 rue Léo Saignat, Bordeaux, 33076, France,
| | - Véronique Deroche-Gamonet
- Neurocentre Magendie, Physiopathologie de la Plasticité Neuronale, U862, INSERM, 146 rue Léo Saignat, Bordeaux, 33076 France ,Neurocentre Magendie, Physiopathologie de la Plasticité Neuronale, U862, University of Bordeaux, 146 rue Léo Saignat, Bordeaux, 33077 France
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57
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Smith MA, Witte MA. The effects of exercise on cocaine self-administration, food-maintained responding, and locomotor activity in female rats: importance of the temporal relationship between physical activity and initial drug exposure. Exp Clin Psychopharmacol 2012; 20:437-46. [PMID: 22924703 PMCID: PMC3752996 DOI: 10.1037/a0029724] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Previous studies have reported that exercise decreases cocaine self-administration in rats with long-term access (8+ weeks) to activity wheels in the home cage. The purpose of this study was to (a) examine the importance of the temporal relationship between physical activity and initial drug exposure, (b) determine the effects of exercise on responding maintained by a nondrug reinforcer (i.e., food), and (c) investigate the effects of exercise on cocaine-induced increases in locomotor activity. To this end, female rats were obtained at weaning and divided into 4 groups: (a) EXE-SED rats were housed in exercise cages for 6 weeks and then transferred to sedentary cages after the first day of behavioral testing; (b) SED-EXE rats were housed in sedentary cages for 6 weeks and then transferred to exercise cages after the first day of behavioral testing; (c) SED-SED rats remained in sedentary cages for the duration of the study; and (d) EXE-EXE rats remained in exercise cages for the duration of the study. Relative to the sedentary group (SED-SED), exercise reduced cocaine self-administration in both groups with access to activity wheels after initial drug exposure (EXE-EXE, SED-EXE) but did not reduce cocaine self-administration in the group with access to activity wheels only before drug exposure (EXE-SED). Exercise also decreased the effects of cocaine on locomotor activity but did not reduce responding maintained by food. These data suggest that exercise may reduce cocaine use in drug-experienced individuals with no prior history of aerobic activity without decreasing other types of positively reinforced behaviors.
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Affiliation(s)
- Mark A Smith
- Department of Psychology, Box 7037, Davidson College, Davidson, NC 28035-7037, USA.
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Dempsey S, Grisel JE. Locomotor sensitization to EtOH: contribution of β-Endorphin. Front Mol Neurosci 2012; 5:87. [PMID: 22952458 PMCID: PMC3430006 DOI: 10.3389/fnmol.2012.00087] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2012] [Accepted: 08/02/2012] [Indexed: 01/21/2023] Open
Abstract
Alcohol use disorders, like all drug addictions, involve a constellation of adaptive changes throughout the brain. Neural activity underlying changes in the rewarding properties of alcohol reflect changes in dopamine transmission in mesolimbic and nigrostriatal pathways and these effects are modulated by endogenous opioids such as β-Endorphin. In order to study the role of β-Endorphin in the development of locomotor sensitization to repeated EtOH exposure, we tested transgenic mice that vary in their capacity to synthesize this peptide as a result of constitutive modification of the Pomc gene. Our results indicate that mice deficient in β-Endorphin show attenuated locomotor activation following an acute injection of EtOH (2.0 g/kg) and, in contrast to wildtype mice, fail to demonstrate locomotor sensitization after 12 days of repeated EtOH injections. These data support the idea that β-Endorphin modulates the locomotor effects of EtOH and contributes to the neuroadaptive changes associated with chronic use.
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Wing VC, Barr MS, Wass CE, Lipsman N, Lozano AM, Daskalakis ZJ, George TP. Brain stimulation methods to treat tobacco addiction. Brain Stimul 2012; 6:221-30. [PMID: 22809824 DOI: 10.1016/j.brs.2012.06.008] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2012] [Revised: 06/08/2012] [Accepted: 06/30/2012] [Indexed: 10/28/2022] Open
Abstract
BACKGROUND Tobacco smoking is the leading cause of preventable deaths worldwide, but many smokers are simply unable to quit. Psychosocial and pharmaceutical treatments have shown modest results on smoking cessation rates, but there is an urgent need to develop treatments with greater efficacy. Brain stimulation methods are gaining increasing interest as possible addiction therapeutics. OBJECTIVES The purpose of this paper is to review the studies that have evaluated brain stimulation techniques on tobacco addiction, and discuss future directions for research in this novel area of addiction interventions. METHODS Electronic and manual literature searches identified fifteen studies that administered repetitive transcranial magnetic stimulation (rTMS), cranial electrostimulation (CES), transcranial direct current stimulation (tDCS) or deep brain stimulation (DBS). RESULTS rTMS was found to be the most well studied method with respect to tobacco addiction. Results indicate that rTMS and tDCS targeted to the dorsolateral prefrontal cortex (DLPFC) were the most efficacious in reducing tobacco cravings, an effect that may be mediated through the brain reward system involved in tobacco addiction. While rTMS was shown to reduce consumption of cigarettes, as yet no brain stimulation technique has been shown to significantly increase abstinence rates. It is possible that the therapeutic effects of rTMS and tDCS may be improved by optimization of stimulation parameters and increasing the duration of treatment. CONCLUSION Although further studies are needed to confirm the ability of brain stimulation methods to treat tobacco addiction, this review indicates that rTMS and tDCS both represent potentially novel treatment modalities.
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Affiliation(s)
- Victoria C Wing
- Biobehavioural Addictions and Concurrent Disorders Research Laboratory, Centre for Addiction and Mental Health, Toronto, ON, Canada.
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60
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Involvement of nucleus accumbens dopamine D1 receptors in ethanol drinking, ethanol-induced conditioned place preference, and ethanol-induced psychomotor sensitization in mice. Psychopharmacology (Berl) 2012; 222:141-53. [PMID: 22222864 DOI: 10.1007/s00213-011-2630-8] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/03/2011] [Accepted: 12/19/2011] [Indexed: 12/24/2022]
Abstract
RATIONALE Dopamine D1 receptor (D1R) signaling has been associated to ethanol consumption and reward in laboratory animals. OBJECTIVES Here, we hypothesize that this receptor, which is located within the nucleus accumbens (NAc) neurons, modulates alcohol reward mechanisms. METHODS To test this hypothesis, we measured alcohol consumption and ethanol-induced psychomotor sensitization and conditioned place preference (CPP) in mice that received bilateral microinjections of small interference RNA (siRNA)-expressing lentiviral vectors (LV-siD1R) producing D1R knock-down. The other group received control (LV-Mock) viral vectors into the NAc. RESULTS There were no differences in the total fluid consumed and also no differences in the amount of ethanol consumed between groups prior to surgery. However, after surgery, the LV-siD1R group consumed less ethanol than the control group. This difference was not associated to taste neophobia. In addition, results have shown that down-regulation of endogenous D1R using viral-mediated siRNA in the NAc significantly decreased ethanol-induced behavioral sensitization as well as acquisition, but not expression, of ethanol-induced place preference. CONCLUSIONS We conclude that decreased D1R expression into the NAc led to reduced ethanol rewarding properties, thereby leading to lower voluntary ethanol consumption. Together, these findings demonstrate that the D1 receptor pathway within the NAc controls ethanol reward and intake.
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Abstract
Neuroimaging studies have been crucial in understanding changes in the various neurotransmitter systems implicated in addiction in the living human brain. Predominantly reduced striatal dopamine transmission appears to play an important role in psychostimulant, alcohol and heroin addiction, while addiction to cannabis may be mediated primarily by the endocannabinoid system. However, the study of other neurotransmitter systems likely involved in addiction, for example glutamate, has been limited by the number and quality of available radiotracers, and data on changes in these systems in the most common addictions are emerging only now. Further studies are needed to understand fully how the interplay of various neurotransmitter systems contributes to addiction and to ultimately help to develop more effective treatment approaches.
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Affiliation(s)
- Nina B L Urban
- Department of Psychiatry, Division of Substance Abuse, Columbia University, New York, NY 10032, USA.
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62
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George O, Le Moal M, Koob GF. Allostasis and addiction: role of the dopamine and corticotropin-releasing factor systems. Physiol Behav 2012; 106:58-64. [PMID: 22108506 PMCID: PMC3288230 DOI: 10.1016/j.physbeh.2011.11.004] [Citation(s) in RCA: 122] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2011] [Revised: 10/31/2011] [Accepted: 11/02/2011] [Indexed: 11/16/2022]
Abstract
Allostasis, originally conceptualized to explain persistent morbidity of arousal and autonomic function, is defined as the process of achieving stability through physiological or behavioral change. Two types of biological processes have been proposed to describe the mechanisms underlying allostasis in drug addiction, a within-system adaptation and a between-system adaptation. In the within-system process, the drug elicits an opposing, neutralizing reaction within the same system in which the drug elicits its primary and unconditioned reinforcing actions, while in the between-system process, different neurobiological systems that the one initially activated by the drug are recruited. In this review, we will focus our interest on alterations in the dopaminergic and corticotropin releasing factor systems as within-system and between-system neuroadaptations respectively, that underlie the opponent process to drugs of abuse. We hypothesize that repeated compromised activity in the dopaminergic system and sustained activation of the CRF-CRF1R system with withdrawal episodes may lead to an allostatic load contributing significantly to the transition to drug addiction.
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Affiliation(s)
- Olivier George
- Committee on the Neurobiology of Addictive Disorders, The Scripps Research Institute, La Jolla, CA 92037, USA.
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63
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Scerbina T, Chatterjee D, Gerlai R. Dopamine receptor antagonism disrupts social preference in zebrafish: a strain comparison study. Amino Acids 2012; 43:2059-72. [PMID: 22491827 DOI: 10.1007/s00726-012-1284-0] [Citation(s) in RCA: 84] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2011] [Accepted: 03/31/2012] [Indexed: 01/03/2023]
Abstract
Zebrafish form shoals in nature and in the laboratory. The sight of conspecifics has been found reinforcing in zebrafish learning tasks. However, the mechanisms of shoaling, and those of its reinforcing properties, are not known. The dopaminergic system has been implicated in reward among other functions and it is also engaged by drugs of abuse as shown in a variety of vertebrates including zebrafish. The ontogenetic changes in dopamine levels and, to a lesser degree, in serotonin levels, have been found to accompany the maturation of shoaling in zebrafish. Thus, we hypothesized that the dopaminergic system may contribute to shoaling in zebrafish. To test this we employed a D1-receptor antagonist and quantified behavioral responses of our subjects using a social preference (shoaling) paradigm. We found significant reduction of social preference induced by the D1-R antagonist, SCH23390, in the AB strain of zebrafish, an alteration that was not accompanied by changes in motor function or vision. We also detected D1-R antagonist-induced changes in the level of dopamine, DOPAC, serotonin and 5HIAA, respectively, in the brain of AB zebrafish as quantified by HPLC with electrochemical detection. We found the antagonist-induced behavioral changes to be absent and the levels of these neurochemicals to be lower in another zebrafish population, SF, demonstrating naturally occurring genetic variability in these traits. We conclude that this variability may be utilized to unravel the mechanisms of social behavior in zebrafish, a line of research that may be extended to other vertebrates including our own species.
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Affiliation(s)
- Tanya Scerbina
- Department of Psychology, University of Toronto Mississauga, 3359 Mississauga Road North, Rm 4020C, Mississauga, ON, L5L 1C6, Canada
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Femenía T, Manzanares J. Increased ethanol intake in prodynorphin knockout mice is associated to changes in opioid receptor function and dopamine transmission. Addict Biol 2012; 17:322-37. [PMID: 21966993 DOI: 10.1111/j.1369-1600.2011.00378.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The purpose of this study was to examine the role of the prodynorphin gene in alcohol sensitivity, preference and vulnerability to alcohol consumption. Handling-induced convulsion (HIC) associated to alcohol, alcohol-induced loss of righting reflex (LORR), hypothermic effects in response to acute ethanol challenge, blood ethanol levels (BELs), conditioned place preference, voluntary ethanol consumption and preference, tyrosine hydroxylase (TH), dopamine transporter (DAT) and proenkephalin (PENK) gene expression, and µ-, δ- and κ-opioid agonist-stimulated [S(35) ]- guanosine 5'-triphosphate-binding autoradiography were studied in prodynorphin knockout (PDYN KO) and wild-type (WT) mice. There were no differences in HIC, LORR or the decrease in body temperature in response to acute ethanol challenge between PDYN KO and WT mice. PDYN KO mice presented higher BEL, higher ethanol-conditioned place preference and more ethanol consumption and preference in a two-bottle choice paradigm than WT mice. These findings were associated with lower TH and higher DAT gene expression in the ventral tegmental area and substantia nigra, and with lower PENK gene expression in the caudate-putamen (CPu), accumbens core (AcbC) and accumbens shell (AcbSh) in PDYN KO. The functional activity of the µ-opioid receptor was lower in the CPu, AcbC, AcbSh and cingulate cortex (Cg) of PDYN KO mice. In contrast, δ- and κ-opioid receptor-binding autoradiographies were increased in the CPu and Cg (δ), and in the CPu, AcbC and Cg (κ) of PDYN KO. These results suggest that deletion of the PDYN gene increased vulnerability for ethanol consumption by altering, at least in part, PENK, TH and DAT gene expression, and µ-, δ- and κ-opioid receptor functional activity in brain areas closely related to ethanol reinforcement.
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Affiliation(s)
- Teresa Femenía
- Instituto de Neurociencias de Alicante, Universidad Miguel Hernández-CSIC, San Juan de Alicante, Spain
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65
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Canales JJ. Deficient plasticity in the hippocampus and the spiral of addiction: focus on adult neurogenesis. Curr Top Behav Neurosci 2012; 15:293-312. [PMID: 22976276 DOI: 10.1007/7854_2012_230] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Addiction is a complex neuropsychiatric disorder which causes disruption at multiple levels, including cognitive, emotional, and behavioral domains. Traditional biological theories of addiction have focused on the mesolimbic dopamine pathway and the nucleus accumbens as anatomical substrates mediating addictive-like behaviors. More recently, we have begun to recognize the engagement and dynamic influence of a much broader circuitry which encompasses the frontal cortex, the amygdala, and the hippocampus. In particular, neurogenesis in the adult hippocampus has become a major focus of attention due to its ability to influence memory, motivation, and affect, all of which are disrupted in addiction. First, I summarize toxicological data that reveal strongly suppressive effects of drug exposure on adult hippocampal neurogenesis. Then, I discuss the impact of deficient neurogenesis on learning and memory function, stress responsiveness and affective behavior, as they relate to addiction. Finally, I examine recent behavioral observations that implicate neurogenesis in the adult hippocampus in the emergence and maintenance of addictive behavior. The evidence reviewed here suggests that deficient neurogenesis is associated with several components of the downward spiraling loop that characterizes addiction, including elevated sensitivity to drug-induced reward and reinforcement, enhanced neurohormonal responsiveness, emergence of a negative affective state, memory impairment, and inflexible behavior.
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Affiliation(s)
- Juan J Canales
- Behavioural Neuroscience, Department of Psychology, The University of Canterbury, Private Bag 4800, 8140, Christchurch, New Zealand,
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Bahi A, Dreyer JL. Involvement of tissue plasminogen activator “tPA” in ethanol-induced locomotor sensitization and conditioned-place preference. Behav Brain Res 2012; 226:250-8. [DOI: 10.1016/j.bbr.2011.09.024] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2011] [Revised: 08/25/2011] [Accepted: 09/12/2011] [Indexed: 12/26/2022]
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Abul-Husn NS, Annangudi SP, Ma'ayan A, Ramos-Ortolaza DL, Stockton SD, Gomes I, Sweedler JV, Devi LA. Chronic morphine alters the presynaptic protein profile: identification of novel molecular targets using proteomics and network analysis. PLoS One 2011; 6:e25535. [PMID: 22043286 PMCID: PMC3197197 DOI: 10.1371/journal.pone.0025535] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2011] [Accepted: 09/06/2011] [Indexed: 02/01/2023] Open
Abstract
Opiates produce significant and persistent changes in synaptic transmission; knowledge of the proteins involved in these changes may help to understand the molecular mechanisms underlying opiate dependence. Using an integrated quantitative proteomics and systems biology approach, we explored changes in the presynaptic protein profile following a paradigm of chronic morphine administration that leads to the development of dependence. For this, we isolated presynaptic fractions from the striata of rats treated with saline or escalating doses of morphine, and analyzed the proteins in these fractions using differential isotopic labeling. We identified 30 proteins that were significantly altered by morphine and integrated them into a protein-protein interaction (PPI) network representing potential morphine-regulated protein complexes. Graph theory-based analysis of this network revealed clusters of densely connected and functionally related morphine-regulated clusters of proteins. One of the clusters contained molecular chaperones thought to be involved in regulation of neurotransmission. Within this cluster, cysteine-string protein (CSP) and the heat shock protein Hsc70 were downregulated by morphine. Interestingly, Hsp90, a heat shock protein that normally interacts with CSP and Hsc70, was upregulated by morphine. Moreover, treatment with the selective Hsp90 inhibitor, geldanamycin, decreased the somatic signs of naloxone-precipitated morphine withdrawal, suggesting that Hsp90 upregulation at the presynapse plays a role in the expression of morphine dependence. Thus, integration of proteomics, network analysis, and behavioral studies has provided a greater understanding of morphine-induced alterations in synaptic composition, and identified a potential novel therapeutic target for opiate dependence.
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Affiliation(s)
- Noura S. Abul-Husn
- Department of Pharmacology and Systems Therapeutics, Mount Sinai School of Medicine, New York, New York, United States of America
| | - Suresh P. Annangudi
- Department of Chemistry, Beckman Institute, University of Illinois at Urban-Champaign, Urbana, Illinois, United States of America
| | - Avi Ma'ayan
- Department of Pharmacology and Systems Therapeutics, Mount Sinai School of Medicine, New York, New York, United States of America
| | - Dinah L. Ramos-Ortolaza
- Department of Pharmacology and Systems Therapeutics, Mount Sinai School of Medicine, New York, New York, United States of America
| | - Steven D. Stockton
- Department of Pharmacology and Systems Therapeutics, Mount Sinai School of Medicine, New York, New York, United States of America
| | - Ivone Gomes
- Department of Pharmacology and Systems Therapeutics, Mount Sinai School of Medicine, New York, New York, United States of America
| | - Jonathan V. Sweedler
- Department of Chemistry, Beckman Institute, University of Illinois at Urban-Champaign, Urbana, Illinois, United States of America
| | - Lakshmi A. Devi
- Department of Pharmacology and Systems Therapeutics, Mount Sinai School of Medicine, New York, New York, United States of America
- * E-mail:
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68
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Yger M, Girault JA. DARPP-32, Jack of All Trades… Master of Which? Front Behav Neurosci 2011; 5:56. [PMID: 21927600 PMCID: PMC3168893 DOI: 10.3389/fnbeh.2011.00056] [Citation(s) in RCA: 81] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2011] [Accepted: 08/16/2011] [Indexed: 02/03/2023] Open
Abstract
DARPP-32 (PPP1R1B) was discovered as a substrate of cAMP-dependent protein kinase (PKA) enriched in dopamine-innervated brain areas. It is one of three related, PKA-regulated inhibitors of protein phosphatase-1 (PP1). These inhibitors seem to have appeared in early vertebrate ancestors, possibly Gnathostomes. DARPP-32 has additional important biochemical properties including inhibition of PKA when phosphorylated by Cdk5 and regulation by casein kinases 1 and 2. It is highly enriched in specific neuronal populations, especially striatal medium-size spiny neurons. As PP1 inhibitor DARPP-32 amplifies and/or mediates many actions of PKA at the plasma membrane and in the cytoplasm, with a broad spectrum of potential targets and functions. DARPP-32 also undergoes a continuous and tightly regulated cytonuclear shuttling. This trafficking is controlled by phosphorylation of Ser-97, which is necessary for nuclear export. When phosphorylated on Thr-34 and dephosphorylated on Ser-97, DARPP-32 can inhibit PP1 in the nucleus and modulate signaling pathways involved in the regulation of chromatin response. Recent work with multiple transgenic and knockout mutant mice has allowed the dissection of DARPP-32 function in striato-nigral and striato-pallidal neurons. It is implicated in the action of therapeutic and abused psychoactive drugs, in prefrontal cortex function, and in sexual behavior. However, the contribution of DARPP-32 in human behavior remains poorly understood. Post-mortem studies in humans suggest possible alterations of DARPP-32 levels in schizophrenia and bipolar disorder. Genetic studies have revealed a polymorphism with possible association with psychological and psychopathological traits. In addition, a short isoform of DARPP-32, t-DARPP, plays a role in cancer, indicating additional signaling properties. Thus, DARPP-32 is a non-essential but tightly regulated signaling hub molecule which may improve the general performance of the neuronal circuits in which it is expressed.
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Affiliation(s)
- Marion Yger
- INSERM UMR-S 839Paris, France
- Université Pierre et Marie CurieParis, France
- Institut du Fer à MoulinParis, France
| | - Jean-Antoine Girault
- INSERM UMR-S 839Paris, France
- Université Pierre et Marie CurieParis, France
- Institut du Fer à MoulinParis, France
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69
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Agster KL, Clark BD, Gao WJ, Shumsky JS, Wang HX, Berridge CW, Waterhouse BD. Experimental strategies for investigating psychostimulant drug actions and prefrontal cortical function in ADHD and related attention disorders. Anat Rec (Hoboken) 2011; 294:1698-712. [PMID: 21901844 DOI: 10.1002/ar.21403] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2010] [Revised: 10/26/2010] [Accepted: 02/14/2011] [Indexed: 01/09/2023]
Abstract
Amphetamine-like psychostimulant drugs have been used for decades to treat a variety of clinical conditions. Methylphenidate (MPH)-Ritalin(R) , a compound that blocks reuptake of synaptically released norepinephrine (NE) and dopamine (DA) in the brain, has been used for more than 30 years in low dose, long-term regimens to treat attention deficit-hyperactive disorder (ADHD) in juveniles, adolescents, and adults. Now, these agents are also becoming increasingly popular among healthy individuals from all walks of life (e.g., military, students) and age groups (teenagers thru senior citizens) to promote wakefulness and improve attention. Although there is agreement regarding the primary biochemical action of MPH, the physiological basis for its efficacy in normal individuals and ADHD patients is lacking. Study of the behavioral and physiological actions of clinically and behaviorally relevant doses of MPH in normal animals provides an opportunity to explore the role of catecholamine transmitters in prefrontal cortical function and attentional processes as they relate to normal operation of brain circuits and ADHD pathology. The goal of ongoing studies has been to: (1) assess the effects of low dose MPH on rodent performance in a well characterized sensory-guided sustained attention task, (2) examine the effects of the same low-dose chronic MPH administration on task-related discharge of prefrontal cortical (PFC) neurons, and (3) investigate the effects of NE and DA on membrane response properties and synaptic transmission in identified subsets of PFC neurons. Combinations of these approaches can be used in adolescent, adult, and aged animals to identify the parameters of cell and neural circuit function that are regulated by MPH and to establish an overarching explanation of how MPH impacts PFC operations from cellular through behavioral functional domains.
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Affiliation(s)
- Kara L Agster
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, Pennsylvania 19129, USA
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70
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Ethanol drinking reduces extracellular dopamine levels in the posterior ventral tegmental area of nondependent alcohol-preferring rats. Alcohol 2011; 45:549-57. [PMID: 21827929 DOI: 10.1016/j.alcohol.2011.02.304] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2010] [Revised: 02/15/2011] [Accepted: 02/16/2011] [Indexed: 11/22/2022]
Abstract
Moderate ethanol exposure produces neuroadaptive changes in the mesocorticolimbic dopamine (DA) system in nondependent rats and increases measures of DA neuronal activity in vitro and in vivo. Moreover, moderate ethanol drinking and moderate systemic exposure elevates extracellular DA levels in mesocorticolimbic projection regions. However, the neuroadaptive changes subsequent to moderate ethanol drinking on basal DA levels have not been investigated in the ventral tegmental area (VTA). In the present study, adult female alcohol-preferring (P) rats were divided into alcohol-naive, alcohol-drinking, and alcohol-deprived groups. The alcohol-drinking group had continuous access to water and ethanol (15%, vol/vol) for 8 weeks. The alcohol-deprived group had 6 weeks of access followed by 2 weeks of ethanol deprivation, 2 weeks of ethanol re-exposure, followed again by 2 weeks of deprivation. The deprived rats demonstrated a robust alcohol deprivation effect (ADE) on ethanol reinstatement. The alcohol-naïve group had continuous access to water only. In the last week of the drinking protocol, all rats were implanted with unilateral microdialysis probes aimed at the posterior VTA and no-net-flux microdialysis was conducted to quantify extracellular DA levels and DA clearance. Results yielded significantly lower basal extracellular DA concentrations in the posterior VTA of the alcohol-drinking group compared with the alcohol-naive and alcohol-deprived groups (3.8±0.3nM vs. 5.0±0.5nM [P<.02] and 4.8±0.4nM, [P<.05], respectively). Extraction fractions were significantly (P<.0002) different between the alcohol-drinking and alcohol-naive groups (72±2% vs. 46±4%, respectively) and not significantly different (P=.051) between alcohol-deprived and alcohol-naive groups (61±6% for the alcohol-deprived group). The data indicate that reductions in basal DA levels within the posterior VTA occur after moderate chronic ethanol intake in nondependent P rats. This reduction may result, in part, from increased DA uptake and may be important for the maintenance of ethanol drinking. These adaptations normalize with ethanol deprivation and may not contribute to the ADE.
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71
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The metabotropic glutamate 2/3 receptor agonist LY379268 blocked nicotine-induced increases in nucleus accumbens shell dopamine only in the presence of a nicotine-associated context in rats. Neuropsychopharmacology 2011; 36:2111-24. [PMID: 21654734 PMCID: PMC3158309 DOI: 10.1038/npp.2011.103] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The metabotropic glutamate 2/3 (mGlu2/3) receptor agonist LY379268 ([-]-2-oxa-4-aminobicyclo [3.1.0] hexane-4,6-dicarboxylate) attenuates both nicotine self-administration and cue-induced nicotine seeking in rats. In this study, the effects of LY379268 (1 mg/kg) or saline pretreatment on nicotine-induced increases in nucleus accumbens (NAcc) shell dopamine were evaluated using in vivo microdialysis under different experimental conditions: (i) nicotine (0.4 mg/kg, base) was experimenter-administered subcutaneously to nicotine-naïve rats; (ii) nicotine was experimenter-administered either subcutaneously (0.4 mg/kg) or by a single experimenter-administered infusion (0.06 mg/kg, base) in rats with a history of nicotine self-administration (nicotine experienced) in the absence of a nicotine-associated context (ie, context and cues associated with nicotine self-administration); (iii) nicotine (0.06 mg/kg) was self-administered or experimenter-administered in nicotine-experienced rats in the presence of a nicotine-associated context. In saline-pretreated nicotine-naïve and nicotine-experienced rats, nicotine increased NAcc shell dopamine regardless of the context used for testing. Interestingly, LY379268 pretreatment blocked nicotine-induced increases in NAcc shell dopamine in nicotine-experienced rats only when tested in the presence of a nicotine-associated context. LY379268 did not block nicotine-induced increases in NAcc shell dopamine in nicotine-naïve or -experienced rats tested in the absence of a nicotine-associated context. These intriguing findings suggest that activation of mGlu2/3 receptors negatively modulates the combined effects of nicotine and nicotine-associated contexts/cues on NAcc dopamine. Thus, these data highlight a critical role for mGlu2/3 receptors in context/cue-induced drug-seeking behavior and suggest a neurochemical mechanism by which mGlu2/3 receptor agonists may promote smoking cessation by preventing relapse induced by the combination of nicotine and nicotine-associated contexts and cues.
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72
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Min C, Cheong SY, Cheong SJ, Kim M, Cho DI, Kim KM. RGS4 exerts inhibitory activities on the signaling of dopamine D2 receptor and D3 receptor through the N-terminal region. Pharmacol Res 2011; 65:213-20. [PMID: 21896332 DOI: 10.1016/j.phrs.2011.08.008] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/11/2011] [Accepted: 08/22/2011] [Indexed: 11/28/2022]
Abstract
Dopamine D(2) receptor and D(3) receptor (D(2)R and D(3)R) are the major targets for current antipsychotic drugs, and their proper regulation has pathological and pharmacological significance. This study was conducted to understand the functional roles and molecular mechanisms of RGS proteins (RGS2, RGS4, and RGS9-2) on the signaling of D(2)R and D(3)R. RGS proteins were co-expressed with D(2)R and D(3)R in HEK-293 cells. The protein interactions between RGS proteins and D(2)R/D(3)R, and effects of RGS proteins on the internalization, signaling, and desensitization of D(2)R/D(3)R were determined. In addition, the RGS4 proteins were subdivided into N-terminal region, RGS domain, and the C-terminal region, and the specific subdomain of RGS4 protein involved in the regulation of the signaling of D(2)R/D(3)R was determined. All of RGS proteins we tested interacted with D(2)R/D(3)R. RGS4 exerted potent inhibitory activities on the signaling of D(2)R/D(3)R. RGS9-2 exerted selective but moderate inhibitory activity on D(3)R and the internalization of D(2)R. RGS2 had no effect. The N-terminal domain of RGS4 was involved in its interaction with D(2)R and D(3)R and was required for the inhibitory activity of the RGS domain. The study for the first time showed that RGS4 is the major RGS protein which interacts through the N-terminal region and exerts potent inhibitory activities on the signaling of D(2)R and D(3)R.
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Affiliation(s)
- Chengchun Min
- Department of Pharmacology, College of Pharmacy, Chonnam National University, Gwang-Ju, Republic of Korea
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73
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Barak S, Carnicella S, Yowell QV, Ron D. Glial cell line-derived neurotrophic factor reverses alcohol-induced allostasis of the mesolimbic dopaminergic system: implications for alcohol reward and seeking. J Neurosci 2011; 31:9885-94. [PMID: 21734280 PMCID: PMC3144766 DOI: 10.1523/jneurosci.1750-11.2011] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2011] [Revised: 05/16/2011] [Accepted: 05/19/2011] [Indexed: 11/21/2022] Open
Abstract
We previously showed that infusion of glial cell line-derived neurotrophic factor (GDNF) into the ventral tegmental area (VTA) rapidly reduces alcohol intake and relapse (Carnicella et al., 2008, 2009a), and increases dopamine (DA) levels in the nucleus accumbens (NAc) of alcohol-naive rats (Wang et al., 2010). Withdrawal from excessive alcohol intake is associated with a reduction in NAc DA levels, whereas drug-induced increases in NAc DA levels are associated with reward. We therefore tested whether GDNF in the VTA reverses alcohol withdrawal-associated DA deficiency and/or possesses rewarding properties. Rats were trained for 7 weeks to consume high levels of alcohol (5.47 ± 0.37 g/kg/24 h) in intermittent access to 20% alcohol in a two-bottle choice procedure. Using in vivo microdialysis, we show that 24 h withdrawal from alcohol causes a substantial reduction in NAc DA overflow, which was reversed by intra-VTA GDNF infusion. Using conditioned place preference (CPP) paradigm, we observed that GDNF on its own does not induce CPP, suggesting that the growth factor is not rewarding. However, GDNF blocked acquisition and expression of alcohol-CPP. In addition, GDNF induced a downward shift in the dose-response curve for operant self-administration of alcohol, further suggesting that GDNF suppresses, rather than substitutes for, the reinforcing effects of alcohol. Our findings suggest that GDNF reduces alcohol-drinking behaviors by reversing an alcohol-induced allostatic DA deficiency in the mesolimbic system. In addition, as it lacks abuse liability, the study further highlights GDNF as a promising target for treatment of alcohol use/abuse disorders.
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Affiliation(s)
- Segev Barak
- The Ernest Gallo Research Center, Department of Neurology, University of California, San Francisco, Emeryville, California 94608
| | - Sebastien Carnicella
- The Ernest Gallo Research Center, Department of Neurology, University of California, San Francisco, Emeryville, California 94608
| | - Quinn V. Yowell
- The Ernest Gallo Research Center, Department of Neurology, University of California, San Francisco, Emeryville, California 94608
| | - Dorit Ron
- The Ernest Gallo Research Center, Department of Neurology, University of California, San Francisco, Emeryville, California 94608
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74
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Suto N, Wise RA, Vezina P. Dorsal as well as ventral striatal lesions affect levels of intravenous cocaine and morphine self-administration in rats. Neurosci Lett 2011; 493:29-32. [PMID: 21315801 PMCID: PMC3065204 DOI: 10.1016/j.neulet.2011.02.011] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2011] [Revised: 02/02/2011] [Accepted: 02/03/2011] [Indexed: 11/30/2022]
Abstract
While the ventral striatum has long been implicated in the rewarding properties of psychomotor stimulants and opiates, little attention has been paid to the possible contribution of more dorsal regions of the striatum. We have thus examined the effects of lesions in three different striatal subregions on cocaine and morphine self-administration. Different groups of rats were trained to self-administer intravenous cocaine (1.0mg/kg/infusion) or morphine (0.5mg/kg/infusion) first under fixed ratio (FR) and then under progressive ratio (PR) schedules of reinforcement. Upon completion of the training, independent groups received bilateral electrolytic or sham lesions of the dorsal portion of the caudate-putamen (dCPu), the ventral portion of the caudate-putamen (vCPu) or the more ventral nucleus accumbens (NAS). Following recovery, they were tested for self-administration of cocaine (0.25, 0.5, 1.0 and 1.5mg/kg/infusion) or morphine (0.125, 0.25, 0.5 and 0.75mg/kg/infusion) under the PR schedule. The PR responding for each drug was significantly reduced in a dose-dependent manner following lesions of dCPu, vCPu and NAS. While the relative effectiveness of these lesions is likely to be specific to the conditions of this experiment, NAS lesions reduced self-administration of each drug to a greater extent than did dCPu or vCPu lesions.
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Affiliation(s)
- Nobuyoshi Suto
- Department of Psychiatry and Behavioral Neuroscience, The University of Chicago, Chicago, IL 60637, USA.
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75
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da Silva Alves F, Schmitz N, Figee M, Abeling N, Hasler G, van der Meer J, Nederveen A, de Haan L, Linszen D, van Amelsvoort T. Dopaminergic modulation of the human reward system: a placebo-controlled dopamine depletion fMRI study. J Psychopharmacol 2011; 25:538-49. [PMID: 20530591 DOI: 10.1177/0269881110367731] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Reward related behaviour is linked to dopaminergic neurotransmission. Our aim was to gain insight into dopaminergic involvement in the human reward system. Combining functional magnetic resonance imaging with dopaminergic depletion by α-methylparatyrosine we measured dopamine-related brain activity in 10 healthy volunteers. In addition to blood-oxygen-level-dependent (BOLD) contrast we assessed the effect of dopaminergic depletion on prolactin response, peripheral markers for dopamine and norepinephrine. In the placebo condition we found increased activation in the left caudate and left cingulate gyrus during anticipation of reward. In the α-methylparatyrosine condition there was no significant brain activation during anticipation of reward or loss. In α-methylparatyrosine, anticipation of reward vs. loss increased activation in the right insula, left frontal, right parietal cortices and right cingulate gyrus. Comparing placebo versus α-methylparatyrosine showed increased activation in the left cingulate gyrus during anticipation of reward and the left medial frontal gyrus during anticipation of loss. α-methylparatyrosine reduced levels of dopamine in urine and homovanillic acid in plasma and increased prolactin. No significant effect of α-methylparatyrosine was found on norepinephrine markers. Our findings implicate distinct patterns of BOLD underlying reward processing following dopamine depletion, suggesting a role of dopaminergic neurotransmission for anticipation of monetary reward.
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76
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McHardy SF, Heck SD, Guediche S, Kalman M, Allen MP, Tu M, Bryce DK, Schmidt AW, Vanase-Frawley M, Callegari E, Doran S, Grahame NJ, McLean S, Liras S. Discovery of CP-866,087, a mu opioid receptor antagonist for the treatment of alcohol abuse and dependence. MEDCHEMCOMM 2011. [DOI: 10.1039/c1md00164g] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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77
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Diana M. The dopamine hypothesis of drug addiction and its potential therapeutic value. Front Psychiatry 2011; 2:64. [PMID: 22144966 PMCID: PMC3225760 DOI: 10.3389/fpsyt.2011.00064] [Citation(s) in RCA: 141] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/14/2011] [Accepted: 11/02/2011] [Indexed: 01/28/2023] Open
Abstract
Dopamine (DA) transmission is deeply affected by drugs of abuse, and alterations in DA function are involved in the various phases of drug addiction and potentially exploitable therapeutically. In particular, basic studies have documented a reduction in the electrophysiological activity of DA neurons in alcohol, opiate, cannabinoid, and other drug-dependent rats. Further, DA release in the Nucleus accumbens (Nacc) is decreased in virtually all drug-dependent rodents. In parallel, these studies are supported by increments in intracranial self stimulation (ICSS) thresholds during withdrawal from alcohol, nicotine, opiates, and other drugs of abuse, thereby suggesting a hypofunction of the neural substrate of ICSS. Accordingly, morphological evaluations fed into realistic computational analysis of the medium spiny neuron of the Nacc, post-synaptic counterpart of DA terminals, show profound changes in structure and function of the entire mesolimbic system. In line with these findings, human imaging studies have shown a reduction of dopamine receptors accompanied by a lesser release of endogenous DA in the ventral striatum of cocaine, heroin, and alcohol-dependent subjects, thereby offering visual proof of the "dopamine-impoverished" addicted human brain. The lasting reduction in physiological activity of the DA system leads to the idea that an increment in its activity, to restore pre-drug levels, may yield significant clinical improvements (reduction of craving, relapse, and drug-seeking/taking). In theory, it may be achieved pharmacologically and/or with novel interventions such as transcranial magnetic stimulation (TMS). Its anatomo-physiological rationale as a possible therapeutic aid in alcoholics and other addicts will be described and proposed as a theoretical framework to be subjected to experimental testing in human addicts.
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Affiliation(s)
- Marco Diana
- 'G. Minardi' Cognitive Neuroscience Laboratory, Department of Drug Sciences, University of Sassari Sassari, Italy
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78
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Ronan PJ, Summers CH. Molecular Signaling and Translational Significance of the Corticotropin Releasing Factor System. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2011; 98:235-92. [DOI: 10.1016/b978-0-12-385506-0.00006-5] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
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79
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McNamara IM, Robinson JK. Conditional stimulation by galanin of saccharin and ethanol consumption under free and response contingent access. Neuropeptides 2010; 44:445-51. [PMID: 20580982 DOI: 10.1016/j.npep.2010.04.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/01/2009] [Revised: 03/19/2010] [Accepted: 04/14/2010] [Indexed: 11/20/2022]
Abstract
Prior research has shown that the neuropeptide galanin strongly stimulates food intake in sated rats when food is made freely available. However, when access to food is made contingent upon lever pressing on a reinforcement schedule, no such stimulation occurs. This dissociation is consistent with the theorized "behavioral energizing" function of the ascending mesolimbic dopamine system, which purports that this ascending dopamine system is involved in only the goal directed effort maintaining (appetitive) and not the hedonic (consummatory) aspects of reward. Further, these results suggest that galanin may play an inhibitory role therein, or itself may be inhibited by mesolimbic dopamine activity underlying instrumental behavior. Prior research into this phenomenon has only utilized caloric foods or water, so the current work assessed the generality of this finding by determining if a similar dissociation also applies to commodities with other properties. For the present experiments, two commodities which varied in the dimensions of palatability and caloric load but which are both known to serve as reinforcers in other settings were chosen. In the first experiment, under the current single commodity free consumption test conditions shown to be sensitive to galanin effects of food and water consumption, galanin did not significantly alter the consumption of caloric laden but poorly palatable 7% alcohol solution. However, in the second experiment, galanin significantly increased free consumption of a highly palatable but non-caloric 0.2% saccharin solution but not when operant responding was required for access to saccharin, extending the basic appetitive-consummatory dissociation observed for food. Taken together, these results suggest that the gustatory properties may be a specific factor involved in galanin stimulation of free consumption, and that there may be a continuum of influence of galanin based on the relative "elasticity" of the commodities as reinforcers.
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Affiliation(s)
- I M McNamara
- Biopsychology Area, Dept. of Psychology, Stony Brook University, Stony Brook, NY, USA
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80
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Iñiguez SD, Vialou V, Warren BL, Cao JL, Alcantara LF, Davis LC, Manojlovic Z, Neve RL, Russo SJ, Han MH, Nestler EJ, Bolaños-Guzmán CA. Extracellular signal-regulated kinase-2 within the ventral tegmental area regulates responses to stress. J Neurosci 2010; 30:7652-63. [PMID: 20519540 PMCID: PMC2895424 DOI: 10.1523/jneurosci.0951-10.2010] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2010] [Revised: 04/09/2010] [Accepted: 04/15/2010] [Indexed: 12/12/2022] Open
Abstract
Neurotrophic factors and their signaling pathways have been implicated in the neurobiological adaptations in response to stress and the regulation of mood-related behaviors. A candidate signaling molecule implicated in mediating these cellular responses is the extracellular signal-regulated kinase (ERK1/2), although its functional role in mood regulation remains to be fully elucidated. Here we show that acute (1 d) or chronic (4 weeks) exposure to unpredictable stress increases phosphorylation of ERK1/2 and of two downstream targets (ribosomal S6 kinase and mitogen- and stress-activated protein kinase 1) within the ventral tegmental area (VTA), an important substrate for motivated behavior and mood regulation. Using herpes simplex virus-mediated gene transfer to assess the functional significance of this ERK induction, we show that overexpressing ERK2 within the VTA increases susceptibility to stress as measured in the forced swim test, responses to unconditioned nociceptive stimuli, and elevated plus maze in Sprague Dawley male rats, and in the tail suspension test and chronic social defeat stress procedure in C57BL/6 male mice. In contrast, blocking ERK2 activity in the VTA produces stress-resistant behavioral responses in these same assays and also blocks a chronic stress-induced reduction in sucrose preference. The effects induced by ERK2 blockade were accompanied by decreases in the firing frequency of VTA dopamine neurons, an important electrophysiological hallmark of resilient-like behavior. Together, these results strongly implicate a role for ERK2 signaling in the VTA as a key modulator of responsiveness to stress and mood-related behaviors.
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MESH Headings
- Action Potentials/physiology
- Analysis of Variance
- Animals
- Animals, Genetically Modified
- Behavior, Animal/physiology
- Dominance-Subordination
- Electroshock/adverse effects
- Escape Reaction/physiology
- Food Preferences/physiology
- Gene Expression Regulation, Enzymologic/physiology
- Green Fluorescent Proteins/genetics
- Hindlimb Suspension/methods
- In Vitro Techniques
- Male
- Maze Learning/physiology
- Mice
- Mice, Inbred C57BL
- Mitogen-Activated Protein Kinase 1/genetics
- Mitogen-Activated Protein Kinase 1/metabolism
- Motor Activity
- Neurons/physiology
- Oncogene Proteins, Fusion
- Pain/enzymology
- Pain/etiology
- Pain/pathology
- Phosphorylation/physiology
- Rats
- Rats, Sprague-Dawley
- Receptors, Fibroblast Growth Factor
- Signal Transduction/physiology
- Simplexvirus/physiology
- Stress, Psychological/enzymology
- Stress, Psychological/etiology
- Stress, Psychological/pathology
- Sucrose/administration & dosage
- Sweetening Agents/administration & dosage
- Swimming/psychology
- Time Factors
- Transduction, Genetic/methods
- Tyrosine 3-Monooxygenase/metabolism
- Ventral Tegmental Area/enzymology
- Ventral Tegmental Area/pathology
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Affiliation(s)
- Sergio D. Iñiguez
- Department of Psychology and Program in Neuroscience, Florida State University, Tallahassee, Florida 32306-4301
| | | | - Brandon L. Warren
- Department of Psychology and Program in Neuroscience, Florida State University, Tallahassee, Florida 32306-4301
| | - Jun-Li Cao
- Department of Pharmacology and Systems Therapeutics, Mount Sinai School of Medicine, New York, New York 10029-6574, and
| | - Lyonna F. Alcantara
- Department of Psychology and Program in Neuroscience, Florida State University, Tallahassee, Florida 32306-4301
| | - Lindsey C. Davis
- Department of Psychology and Program in Neuroscience, Florida State University, Tallahassee, Florida 32306-4301
| | - Zarko Manojlovic
- Department of Psychology and Program in Neuroscience, Florida State University, Tallahassee, Florida 32306-4301
| | - Rachael L. Neve
- Massachusetts Institute of Technology, Cambridge, Massachusetts 02139-4307
| | | | - Ming-Hu Han
- Fishberg Department of Neuroscience and
- Department of Pharmacology and Systems Therapeutics, Mount Sinai School of Medicine, New York, New York 10029-6574, and
| | | | - Carlos A. Bolaños-Guzmán
- Department of Psychology and Program in Neuroscience, Florida State University, Tallahassee, Florida 32306-4301
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81
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Guarraci FA. "Sex, drugs and the brain": the interaction between drugs of abuse and sexual behavior in the female rat. Horm Behav 2010; 58:138-48. [PMID: 20025882 DOI: 10.1016/j.yhbeh.2009.12.002] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/09/2009] [Revised: 12/02/2009] [Accepted: 12/04/2009] [Indexed: 10/20/2022]
Abstract
Preclinical and clinical research investigating female sexual motivation has lagged behind research on male sexual function. The present review summarizes recent advances in our understanding of the specific roles of various brain areas, as well as our understanding of the role of dopaminergic neurotransmission in sexual motivation of the female rat. A number of behavioral paradigms that can be used to thoroughly evaluate sexual behavior in the female rat are first discussed. Although traditional assessment of the reflexive, lordosis posture has been useful in understanding the neuroanatomical and neurochemical systems that contribute to copulatory behavior, the additional behavioral paradigms described in this review have helped us expand our understanding of appetitive and consumatory behavioral patterns that better assess sexual motivation - the equivalent of "desire" in humans. A summary of numerous lesion studies indicates that different areas of the brain, including forebrain and midbrain structures, work together to produce the complex repertoire of female sexual behavior. In addition, by investigating the effects of commonly addictive drugs, we are beginning to elucidate the role of dopaminergic neurotransmission in female sexual motivation. Consequently, research in this area may contribute to meaningful advances in the treatment of human female sexual dysfunction.
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Affiliation(s)
- Fay A Guarraci
- Department of Psychology, Southwestern University, Georgetown, TX 78626, USA.
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82
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George O, Koob GF. Individual differences in prefrontal cortex function and the transition from drug use to drug dependence. Neurosci Biobehav Rev 2010; 35:232-47. [PMID: 20493211 DOI: 10.1016/j.neubiorev.2010.05.002] [Citation(s) in RCA: 221] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2009] [Revised: 05/10/2010] [Accepted: 05/12/2010] [Indexed: 12/17/2022]
Abstract
Several neuropsychological hypotheses have been formulated to explain the transition to addiction, including hedonic allostasis, incentive salience, and the development of habits. A key feature of addiction that remains to be explored is the important individual variability observed in the propensity to self-administer drugs, the sensitivity to drug-associated cues, the severity of the withdrawal state, and the ability to quit. In this review, we suggest that the concept of self-regulation, combined with the concept of modularity of cognitive function, may aid in the understanding of the neural basis of individual differences in the vulnerability to drugs and the transition to addiction. The thesis of this review is that drug addiction involves a failure of the different subcomponents of the executive systems controlling key cognitive modules that process reward, pain, stress, emotion, habits, and decision-making. A subhypothesis is that the different patterns of drug addiction and individual differences in the transition to addiction may emerge from differential vulnerability in one or more of the subcomponents.
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Affiliation(s)
- Olivier George
- Committee on the Neurobiology of Addictive Disorders, The Scripps Research Institute, 10550 North Torrey Pines Road, SP30-2400, La Jolla, CA 92037, USA.
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83
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Morzorati SL, Marunde RL, Downey D. Limited access to ethanol increases the number of spontaneously active dopamine neurons in the posterior ventral tegmental area of nondependent P rats. Alcohol 2010; 44:257-64. [PMID: 20682193 DOI: 10.1016/j.alcohol.2010.02.009] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2009] [Revised: 01/28/2010] [Accepted: 02/10/2010] [Indexed: 10/19/2022]
Abstract
Microdialysis experiments in alcohol-preferring (P) rats have shown that chronic ethanol exposure increases extracellular levels of dopamine (DA) in the nucleus accumbens. Because DA neuronal activity contributes to the regulation of DA overflow in terminal regions, we hypothesized that posterior ventral tegmental area (VTA) DA neuronal activity (firing frequency, burst activity, and/or the number of spontaneously active DA neurons) would be increased in P rats consuming ethanol compared with P rats consuming only water. In vivo electrophysiological techniques were used to evaluate the activity of single DA neurons in the posterior VTA. Our findings show that voluntary ethanol intake by nondependent P rats significantly increased the number of spontaneously active DA neurons in the posterior VTA compared with P rats that consumed only water. Firing frequency and burst activity did not differ between the two groups. These results suggest that adaptive changes occur in the mesolimbic DA system of nondependent P rats to increase the excitability of posterior VTA DA neurons and enhance DA release from nerve terminals in the nucleus accumbens.
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84
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Abstract
There is no specialized alcohol addiction area in the brain; rather, alcohol acts on a wide range of excitatory and inhibitory nervous networks to modulate neurotransmitters actions by binding with and altering the function of specific proteins. With no hemato-encephalic barrier for alcohol, its actions are strongly related to the amount of intake. Heavy alcohol intake is associated with both structural and functional changes in the central nervous system with long-term neuronal adaptive changes contributing to the phenomena of tolerance and withdrawal. The effects of alcohol on the function of neuronal networks are heterogeneous. Because ethanol affects neural activity in some brain sites but is without effect in others, its actions are analyzed in terms of integrated connectivities in the functional circuitry of neuronal networks, which are of particular interest because of the cognitive interactions discussed in the manuscripts contributing to this review. Recent molecular data are reviewed as a support for the other contributions dealing with cognitive disturbances related to alcohol acute and addicted consumption.
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Affiliation(s)
- Claude Tomberg
- Brain Research Unit, Faculty of Medicine and CENOLI, Free University of Brussels, Belgium
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85
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Abstract
There has been increasing interest in the ability of neuropeptides involved in feeding to modulate circuits important for responses to drugs of abuse. A number of peptides with effects on hypothalamic function also modulate the mesolimbic dopamine system (ventral tegmental area and nucleus accumbens). Similarly, common stress-related pathways can modulate food intake, drug reward and symptoms of drug withdrawal. Galanin promotes food intake and the analgesic properties of opiates, thus it initially seemed possible that galanin might potentiate opiate reinforcement. Instead, galanin agonists decrease opiate reward, measured by conditioned place preference, and opiate withdrawal signs, whereas opiate reward and withdrawal are increased in knockout mice lacking galanin. This is consistent with studies showing that galanin decreases activity-evoked dopamine release in striatal slices and decreases the firing rate of noradrenergic neurons in locus coeruleus, areas involved in drug reward and withdrawal, respectively. These data suggest that polymorphisms in genes encoding galanin or galanin receptors might be associated with susceptibility to opiate abuse. Further, galanin receptors might be potential targets for development of novel treatments for addiction.
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Affiliation(s)
- Marina R Picciotto
- Department of Psychiatry, Yale University School of Medicine, 34 Park Street, 3rd Floor Research, New Haven, CT 06508, USA.
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86
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Oz M, Jaligam V, Galadari S, Petroianu G, Shuba YM, Shippenberg TS. The endogenous cannabinoid, anandamide, inhibits dopamine transporter function by a receptor-independent mechanism. J Neurochem 2009; 112:1454-64. [PMID: 20050977 DOI: 10.1111/j.1471-4159.2009.06557.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The endocannabinoid, anandamide (AEA), modulates the activity of the dopamine transporter (DAT) in heterologous cells and synaptosomal preparations. The cellular mechanisms mediating this effect are unknown. The present studies employed live cell imaging techniques and the fluorescent, high affinity DAT substrate, 4-(4-(dimethylamino)-styryl)-N-methylpyridinium (ASP(+)), to address this issue. AEA addition to EM4 cells expressing yellow fluorescent protein-tagged human DAT (hDAT) produced a concentration-dependent inhibition of ASP(+) accumulation (IC(50): 3.2 +/- 0.8 microM). This effect occurred within 1 min after AEA addition and persisted for 10 min thereafter. Pertussis toxin did not attenuate the effects of AEA suggesting a mechanism independent of G(i)/G(o) coupled receptors. The amidohydrolase inhibitor, phenylmethylsulfonyl fluoride (0.2 mM), failed to alter the AEA-evoked inhibition of ASP(+) accumulation. Methanandamide (10 microM), a metabolically stable analogue of AEA inhibited accumulation but arachidonic acid (10 microM) was without effect suggesting that the effects of AEA are not mediated by its metabolic products. The extent of AEA inhibition of ASP(+) accumulation was not altered in cells pre-treated with 1 microM URB597, a specific and potent fatty acid amide hydrolase inhibitor, and the cyclooxygenase inhibitor, indomethacin (5 microM) Live cell imaging revealed a significant redistribution of hDAT from the membrane to the cytosol in response to AEA treatment (10 microM; 10 min). Similarly biotinylation experiments revealed that the decrease in DAT function was associated with a reduction in hDAT cell surface expression. These results demonstrate that AEA modulates DAT function via a cannabinoid receptor-independent mechanism and suggest that AEA may produces this effect, in part, by modulating DAT trafficking.
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Affiliation(s)
- Murat Oz
- Integrative Neuroscience Section, Intramural Research Program, National Institute on Drug Abuse, National Institutes of Health, US Department of Health and Human Services, Baltimore, Maryland 21224, USA
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87
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Abstract
Human infants are often exposed to opiates chronically but the mechanisms by which opiates induce dependence in the infant are not well studied. In the adult the brain regions involved in the physical signs of opiate withdrawal include the periaqueductal gray area, the locus coeruleus, amygdala, ventral tegmental area, nucleus accumbens, hypothalamus, and spinal cord. Microinjection studies show that many of these brain regions are involved in opiate withdrawal in the infant rat. Our goal here was to determine if these regions become metabolically active during physical withdrawal from morphine in the infant rat as they do in the adult. Following chronic morphine or saline treatment, withdrawal was precipitated in 7-day-old pups with the opiate antagonist naltrexone. Cells positive for Fos-like immunoreactivity were quantified within select brain regions. Increased Fos-like labeled cells were found in the periaqueductal gray, nucleus accumbens, locus coeruleus, and spinal cord. These are consistent with other studies showing that the neural circuits underlying the physical signs of opiate withdrawal are similar in the infant and adult.
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Affiliation(s)
- Anika A McPhie
- Department of Psychology, Hunter College and the Graduate Center, City University of New York, New York, NY 10016, USA
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88
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Abstract
Tobacco use is predicted to result in over 1 billion deaths worldwide by the end of the 21(st) century. How genetic variation contributes to the observed differential predisposition in the human population to drug dependence is unknown. The zebrafish (Danio rerio) is an emerging vertebrate model system for understanding the genetics of behavior. We developed a nicotine behavioral assay in zebrafish and applied it in a forward genetic screen using gene-breaking transposon mutagenesis. We used this method to molecularly characterize bdav/cct8 and hbog/gabbr1.2 as mutations with altered nicotine response. Each have a single human ortholog, identifying two points for potential scientific, diagnostic, and drug development for nicotine biology and cessation therapeutics. We show this insertional method generates mutant alleles that are reversible through Cre-mediated recombination, representing a conditional mutation system for the zebrafish. The combination of this reporter-tagged insertional mutagen approach and zebrafish provides a powerful platform for a rich array of questions amenable to genetic-based scientific inquiry, including the basis of behavior, epigenetics, plasticity, stress, memory, and learning.
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89
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Clague J, Cinciripini P, Blalock J, Wu X, Hudmon KS. The D2 dopamine receptor gene and nicotine dependence among bladder cancer patients and controls. Behav Genet 2009; 40:49-58. [PMID: 19842028 DOI: 10.1007/s10519-009-9301-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2009] [Accepted: 09/26/2009] [Indexed: 11/28/2022]
Abstract
Multiple twin, family, and genetic studies have rendered substantial evidence supporting an association between hereditary factors and smoking initiation and maintenance. To investigate further the relationships between the DRD2 genotypes, cigarette use and nicotine dependence, we examined the prevalence of polymorphisms in the TaqIA (A1 and A2) and the TaqIB (B1 and B2) alleles among a series of 608 non-Hispanic White bladder cancer patients and 608 matched controls. Among ever-smoking controls, A1 and B1 genotypes exhibited a greater smoking intensity and were significantly younger at the age of initiation than A2A2 or B2B2 genotypes (two-sided P < 0.05). Among former smoking cases, persons with the A1 genotypes exhibited significantly higher mean pack-years and years of smoking, and were younger at the age of initiation than were persons with the A2A2 genotype (two-sided P < 0.05). Additionally, current smokers with the A1 genotypes reported fewer quit attempts than those with the A2A2 genotype (two-sided P < 0.01). The present study suggests that the DRD2 alleles A1 and B1 confer greater vulnerability to tobacco use.
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Affiliation(s)
- Jessica Clague
- Department of Epidemiology, Unit 1340, The University of Texas M D Anderson Cancer Center, 1155 Pressler Blvd. Unit 1340, Houston, TX 77030, USA
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90
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Abstract
Persistent symptoms of depression suggest the involvement of stable molecular adaptations in brain, which may be reflected at the level of chromatin remodeling. We find that chronic social defeat stress in mice causes a transient decrease, followed by a persistent increase, in levels of acetylated histone H3 in the nucleus accumbens, an important limbic brain region. This persistent increase in H3 acetylation is associated with decreased levels of histone deacetylase 2 (HDAC2) in the nucleus accumbens. Similar effects were observed in the nucleus accumbens of depressed humans studied postmortem. These changes in H3 acetylation and HDAC2 expression mediate long-lasting positive neuronal adaptations, since infusion of HDAC inhibitors into the nucleus accumbens, which increases histone acetylation, exerts robust antidepressant-like effects in the social defeat paradigm and other behavioral assays. HDAC inhibitor [N-(2-aminophenyl)-4-[N-(pyridine-3-ylmethoxy-carbonyl)aminomethyl]benzamide (MS-275)] infusion also reverses the effects of chronic defeat stress on global patterns of gene expression in the nucleus accumbens, as determined by microarray analysis, with striking similarities to the effects of the standard antidepressant fluoxetine. Stress-regulated genes whose expression is normalized selectively by MS-275 may provide promising targets for the future development of novel antidepressant treatments. Together, these findings provide new insight into the underlying molecular mechanisms of depression and antidepressant action, and support the antidepressant potential of HDAC inhibitors and perhaps other agents that act at the level of chromatin structure.
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91
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Schramm-Sapyta NL, Walker QD, Caster JM, Levin ED, Kuhn CM. Are adolescents more vulnerable to drug addiction than adults? Evidence from animal models. Psychopharmacology (Berl) 2009; 206:1-21. [PMID: 19547960 PMCID: PMC3025448 DOI: 10.1007/s00213-009-1585-5] [Citation(s) in RCA: 155] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/07/2008] [Accepted: 05/26/2009] [Indexed: 01/26/2023]
Abstract
BACKGROUND AND RATIONALE Epidemiological evidence suggests that people who begin experimenting with drugs of abuse during early adolescence are more likely to develop substance use disorders (SUDs), but this correlation does not guarantee causation. Animal models, in which age of onset can be tightly controlled, offer a platform for testing causality. Many animal models address drug effects that might promote or discourage drug intake and drug-induced neuroplasticity. METHODS We have reviewed the preclinical literature to investigate whether adolescent rodents are differentially sensitive to rewarding, reinforcing, aversive, locomotor, and withdrawal-induced effects of drugs of abuse. RESULTS AND CONCLUSIONS The rodent model literature consistently suggests that the balance of rewarding and aversive effects of drugs of abuse is tipped toward reward in adolescence. However, increased reward does not consistently lead to increased voluntary intake: age effects on voluntary intake are drug and method specific. On the other hand, adolescents are consistently less sensitive to withdrawal effects, which could protect against compulsive drug seeking. Studies examining neuronal function have revealed several age-related effects but have yet to link these effects to vulnerability to SUDs. Taken together, the findings suggest factors which may promote recreational drug use in adolescents, but evidence relating to pathological drug-seeking behavior is lacking. A call is made for future studies to address this gap using behavioral models of pathological drug seeking and for neurobiologic studies to more directly link age effects to SUD vulnerability.
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92
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Smith MA, Greene-Naples JL, Lyle MA, Iordanou JC, Felder JN. The effects of repeated opioid administration on locomotor activity: I. Opposing actions of mu and kappa receptors. J Pharmacol Exp Ther 2009; 330:468-75. [PMID: 19403853 DOI: 10.1124/jpet.108.150011] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Repeated administration of many addictive drugs leads to a progressive increase in their locomotor effects. This increase in locomotor activity often develops concomitantly with increases in their positive-reinforcing effects, which are believed to contribute to the etiology of substance use disorders. The purpose of this study was to examine changes in sensitivity to the locomotor effects of opioids after their repeated administration and to determine the role of mu and kappa receptors in mediating these effects. Separate groups of rats were treated with opioid receptor agonists and antagonists every other day for 10 days, and changes in locomotor activity were measured. Repeated administration of the mu agonists, morphine and buprenorphine, produced a progressive increase in locomotor activity during the treatment period, and this effect was blocked by coadministration of the opioid antagonist naltrexone. The kappa agonist spiradoline decreased locomotor activity when administered alone and blocked the progressive increase in locomotor activity produced by morphine. The ability of spiradoline to block morphine-induced increases in locomotor activity was itself blocked by pretreatment with the kappa antagonist nor-binaltorphimine. Repeated administration of high doses, but not low or moderate doses, of the mixed mu/kappa agonists butorphanol, nalbuphine, and nalorphine produced a progressive increase in locomotor activity during the treatment period. Doses of butorphanol, nalbuphine, and nalorphine that failed to produce a progressive increase in locomotor activity when administered alone did so when subjects were pretreated with nor-binaltorphimine. These findings suggest that mu and kappa receptors have functionally opposing effects on opioid-mediated locomotor activity and sensitization-related processes.
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Affiliation(s)
- Mark A Smith
- Department of Psychology and Program in Neuroscience, Davidson College, Davidson, North Carolina, USA
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93
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Leri F, Zhou Y, Goddard B, Levy A, Jacklin D, Kreek MJ. Steady-state methadone blocks cocaine seeking and cocaine-induced gene expression alterations in the rat brain. Eur Neuropsychopharmacol 2009; 19:238-49. [PMID: 18990547 PMCID: PMC2900837 DOI: 10.1016/j.euroneuro.2008.09.004] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/04/2008] [Revised: 08/22/2008] [Accepted: 09/30/2008] [Indexed: 11/26/2022]
Abstract
To elucidate the effects of steady-state methadone exposure on responding to cocaine conditioned stimuli and on cocaine-induced alterations in central opioid, hypocretin/orexin, and D2 receptor systems, male Sprague-Dawley rats received intravenous infusions of 1 mg/kg/inf cocaine paired with an audiovisual stimulus over three days of conditioning. Then, mini pumps releasing vehicle or 30 mg/kg/day methadone were implanted (SC), and lever pressing for the stimulus was assessed in the absence of cocaine and after a cocaine prime (20 mg/kg, IP). It was found that rats treated with vehicle, but not methadone, responded for the cocaine conditioned stimulus and displayed elevated mu-opioid receptor mRNA expression in the nucleus accumbens core and basolateral amygdala, reduced hypocretin/orexin mRNA in the lateral hypothalamus, and reduced D2 receptor mRNA in the caudate-putamen. This is the first demonstration that steady-state methadone administered after cocaine exposure blocks cocaine-induced behavioral and neural adaptations.
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MESH Headings
- Acoustic Stimulation/methods
- Analgesics, Opioid/administration & dosage
- Analysis of Variance
- Animals
- Behavior, Animal/drug effects
- Brain/drug effects
- Cocaine/pharmacology
- Cocaine-Related Disorders/drug therapy
- Cocaine-Related Disorders/metabolism
- Conditioning, Classical/drug effects
- Conditioning, Operant/drug effects
- Dopamine Uptake Inhibitors/pharmacology
- Drug Administration Schedule
- Drug Delivery Systems/methods
- Dynorphins/genetics
- Dynorphins/metabolism
- Gene Expression Regulation/drug effects
- Intracellular Signaling Peptides and Proteins/genetics
- Intracellular Signaling Peptides and Proteins/metabolism
- Locomotion/drug effects
- Male
- Methadone/administration & dosage
- Neuropeptides/genetics
- Neuropeptides/metabolism
- Orexins
- Photic Stimulation/methods
- RNA, Messenger/metabolism
- Rats
- Rats, Sprague-Dawley
- Receptors, Dopamine D2/genetics
- Receptors, Dopamine D2/metabolism
- Receptors, Opioid, mu/genetics
- Receptors, Opioid, mu/metabolism
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Affiliation(s)
- Francesco Leri
- Department of Psychology, University of Guelph, Guelph, Canada.
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94
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Abstract
Accumulating evidence suggests that the antecedents, consequences, and mechanisms of drug abuse and dependence are not identical in males and females and that gender may be an important variable in treatment and prevention. Although there has been a decline in smoking prevalence in developed countries, females are less successful in quitting. Tobacco use is accepted to be a form of addiction, which manifests sex differences. There is also evidence for sex differences in the central effects of nicotine in laboratory animals. Although social factors impact smoking substantially in humans, findings from nonhuman subjects in controlled experiments provide support that sex differences in nicotine/tobacco addiction have a biological basis. Differences in the pharmacokinetic properties of nicotine or the effect of gonadal hormones may underlie some but not all sex differences observed. Laboratory-based information is very important in developing treatment strategies. Literature findings suggest that including sex as a factor in nicotine/tobacco-related studies will improve our success rates in individually tailored smoking cessation programs.
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Affiliation(s)
- Sakire Pogun
- Ege University Center for Brain Research, Ege University, Bornova, Izmir, 35100, Turkey.
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95
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Alvarez-Jaimes L, Polis I, Parsons LH. Regional Influence of Cannabinoid CB 1 Receptors in the Regulation of Ethanol Self-Administration by Wistar Rats. THE OPEN NEUROPSYCHOPHARMACOLOGY JOURNAL 2009; 2:77-85. [PMID: 27974944 PMCID: PMC5152943 DOI: 10.2174/1876523800902020077] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Substantial evidence suggests a facilitatory influence of cannabinoid CB1 receptors in the modulation of ethanol consumption by rodents. Studies performed in rats selectively bred for high alcohol preference point to an involvement of CB1 receptors in the nucleus accumbens (NAC), ventral tegmental area (VTA) and medial prefrontal cortex (mPFC) in the modulation ethanol self-administration. However, the neural mechanisms through which CB1 receptors regulate ethanol intake in out-bred Wistar rats have not been investigated. The present study evaluated alterations in ethanol self-administration induced by localized infusions of the CB1 receptor antagonist SR141716A (0, 1 and 3 μg/side) into the NAC, anterior and posterior VTA and mPFC. Separate groups of Wistar rats were trained to operantly respond for an oral ethanol solution and prepared with bilateral injection cannulae aimed at each brain region. Results revealed significant decreases in ethanol intake following intra-NAC SR141716A administration, consistent with our prior observation of ethanol-induced increases extracellular 2-arachidonoyl glycerol (2-AG) in this brain region. We also observed a significant dose-dependent reduction in ethanol intake following SR141716A administration into the posterior, but not anterior VTA, consistent with evidence of a specific involvement of the posterior VTA in the regulation of ethanol intake. Ethanol consumption was unaltered following intra-mPFC SR141716A administration and ethanol self-administration did not induce robust changes in anandamide or 2-AG levels in mPFC microdialysates. These findings implicate an involvement of CB1 receptors in the NAC and posterior VTA, but not anterior VTA and mPFC in the regulation of ethanol self-administration behavior by outbred Wistar rats.
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Affiliation(s)
- Lily Alvarez-Jaimes
- Committee on the Neurobiology of Addictive Disorders, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Ilham Polis
- Committee on the Neurobiology of Addictive Disorders, The Scripps Research Institute, La Jolla, CA 92037, USA
| | - Loren H. Parsons
- Committee on the Neurobiology of Addictive Disorders, The Scripps Research Institute, La Jolla, CA 92037, USA
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96
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Elisabetsky E, Castilhos ZC. Plants Used as Analgesics by Amazonian Caboclos as a Basis for Selecting Plants for Investigation. ACTA ACUST UNITED AC 2008. [DOI: 10.3109/13880209009082838] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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97
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Kitanaka N, Kitanaka J, Hall FS, Tatsuta T, Morita Y, Takemura M, Wang XB, Uhl GR. Alterations in the levels of heterotrimeric G protein subunits induced by psychostimulants, opiates, barbiturates, and ethanol: Implications for drug dependence, tolerance, and withdrawal. Synapse 2008; 62:689-99. [PMID: 18566973 DOI: 10.1002/syn.20543] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Neuronal adaptations have been found to occur in multiple brain regions after chronic intake of abused drugs, and are therefore thought to underlie drug dependence, tolerance, and withdrawal. Pathophysiological changes in drug responsiveness as well as behavioral sequelae of chronic drug exposure are thought to depend largely upon the altered state of heterotrimeric GTP binding protein (G protein)-coupled receptor (GPCR)-G protein interactions. Responsiveness of GPCR-related intracellular signaling systems to drugs of abuse is heterogeneous, depending on the types of intracellular effectors to which the specific Galpha protein subtypes are coupled and GPCR-G protein coupling efficiency, factors influenced by the class of drug, expression levels of G protein subunits, and drug treatment regimens. To enhance understanding of the molecular mechanisms that underlie the development of pathophysiological states resulting from chronic intake of abused drugs, this review focuses on alterations in the expression levels of G protein subunits induced by various drugs of abuse. Changes in these mechanisms appear to be specific to particular drugs of abuse, and specific conditions of drug treatment.
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Affiliation(s)
- Nobue Kitanaka
- Department of Pharmacology, Hyogo College of Medicine, 1-1 Mukogawa-cho, Nishinomiya, Hyogo, Japan.
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98
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Wise RA, Wang B, You ZB. Cocaine serves as a peripheral interoceptive conditioned stimulus for central glutamate and dopamine release. PLoS One 2008; 3:e2846. [PMID: 18682722 PMCID: PMC2475658 DOI: 10.1371/journal.pone.0002846] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2008] [Accepted: 07/08/2008] [Indexed: 11/18/2022] Open
Abstract
Intravenous injections of cocaine HCl are habit-forming because, among their many actions, they elevate extracellular dopamine levels in the terminal fields of the mesocorticolimbic dopamine system. This action, thought to be very important for cocaine's strong addiction liability, is believed to have very short latency and is assumed to reflect rapid brain entry and pharmacokinetics of the drug. However, while intravenous cocaine HCl has almost immediate effects on behavior and extracellular dopamine levels, recent evidence suggests that its central pharmacological effects are not evident until 10 or more seconds after IV injection. Thus the immediate effects of a given intravenous cocaine injection on extracellular dopamine concentration and behavior appear to occur before there is sufficient time for cocaine to act centrally as a dopamine uptake inhibitor. To explore the contribution of peripheral effects of cocaine to the early activation of the dopamine system, we used brain microdialysis to measure the effects of cocaine methiodide (MI)--a cocaine analogue that does not cross the blood brain barrier--on glutamate (excitatory) input to the dopamine cells. IP injections of cocaine MI were ineffective in cocaine-naïve animals but stimulated ventral tegmental glutamate release in rats previously trained to lever-press for cocaine HCl. This peripherally triggered glutamate input was sufficient to reinstate cocaine-seeking in previously trained animals that had undergone extinction of the habit. These findings offer an explanation for short-latency behavioral responses and immediate dopamine elevations seen following cocaine injections in cocaine-experienced but not cocaine-naïve animals.
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Affiliation(s)
- Roy A Wise
- Department of Health and Human Services, Behavioral Neuroscience Branch, Intramural Research Program, National Institute on Drug Abuse, National Institutes of Health, Baltimore, Maryland, United States of America.
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99
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Abstract
The mechanisms underlying responses to drugs of abuse have been widely investigated; however, less is known about pathways normally protective against the development of drug reinforcement. These pathways are also important since they may regulate individual differences in vulnerability to addiction. The neuropeptide galanin and its binding sites are expressed in brain areas important for drug reward. Previous studies have shown that centrally infused galanin attenuates morphine place preference and peripheral injection of galnon, a galanin agonist, decreases opiate withdrawal signs. The current studies in galanin knockout (GKO) mice examined the hypothesis that galanin is an endogenous negative regulator of opiate reward and identified downstream signaling pathways regulated by galanin. We show that GKO mice demonstrate increased locomotor activation following morphine administration, which is inhibited by acute administration of galnon. GKO mice also show enhanced morphine place preference, supporting the idea that galanin normally antagonizes opiate reward. In addition, morphine-induced ERK1/2 phosphorylation was increased in the VTA of both wild-type and GKO mice, but only the GKO mice showed increases in ERK1/2 and CREB phosphorylation in the amygdala or nucleus accumbens. Furthermore, a single systemic injection of galnon in GKO mice was sufficient to reverse some of the biochemical changes brought about by morphine administration. These data suggest that galanin normally attenuates behavioral and neurochemical effects of opiates; thus, galanin agonists may represent a new class of therapeutic targets for opiate addiction.
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Maric T, Tobin S, Quinn T, Shalev U. Food deprivation-like effects of neuropeptide Y on heroin self-administration and reinstatement of heroin seeking in rats. Behav Brain Res 2008; 194:39-43. [PMID: 18639589 DOI: 10.1016/j.bbr.2008.06.023] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2008] [Revised: 06/06/2008] [Accepted: 06/18/2008] [Indexed: 10/21/2022]
Abstract
Numerous findings suggest that drug seeking and ingestive behaviors share common neurobiological mechanisms, but the relevant pathways are unknown. Dietary manipulations result in changes in endocrine the and/or neuropeptide signals, such as the hormones leptin and ghrelin, which are dynamically linked to energy balance and the regulation of feeding behavior. We have recently demonstrated that food deprivation-induced reinstatement of heroin seeking can be blocked with leptin, and others have suggested a role for ghrelin in drug-related behaviors. The feeding-relevant effects of leptin and ghrelin involve the inhibition or activation, respectively, of neuropeptide Y/agouti-related peptide (NPY/AGRP) neurons in the hypothalamus. However, the effects of NPY, a highly potent orexigenic peptide, on drug-related behaviors have not been thoroughly studied. Here we examined the effect of acute NPY administration on the rate of heroin self-administration and the reinstatement of extinguished heroin-seeking behavior. Heroin intake (0.05mg/kg/infusion) was tested using a self-administration procedure (FR-1), 10-min post-NPY injections (0.0, 4.0, and 10microg/rat, ICV). In a different group of rats, NPY-induced reinstatement (0.0, 4.0, and 10microg/rat, ICV) of extinguished heroin seeking was assessed. NPY injections increased on-going heroin self-administration, and induced a reinstatement of extinguished heroin-seeking behavior. These findings suggest that NPY can modulate the rewarding and conditioned reinforcing effects of drugs of abuse.
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Affiliation(s)
- Tia Maric
- Department of Psychology, Center for Studies in Behavioral Neurobiology, Concordia University, 7141 Sherbrooke Street West, H4B 1R6, Montreal, Quebec Canada
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