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Han X, Jing MY, Zhao TY, Wu N, Song R, Li J. Role of dopamine projections from ventral tegmental area to nucleus accumbens and medial prefrontal cortex in reinforcement behaviors assessed using optogenetic manipulation. Metab Brain Dis 2017; 32:1491-1502. [PMID: 28523568 DOI: 10.1007/s11011-017-0023-3] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/06/2017] [Accepted: 04/28/2017] [Indexed: 01/06/2023]
Abstract
Dopamine (DA) neurons in the ventral tegmental area (VTA) are predicted to play important roles in reward. In pharmacological studies, the rewarding effects of methamphetamine are mediated by DA neurons localized in the VTA. The nucleus accumbens (NAc) and medial prefrontal cortices (mPFC) are the main projections from the VTA. However, the role of these projections remains unclear, particularly the mPFC projections. In the present study, DAT-Cre transgenic mice received an injection of adeno-associated viral vectors encoding channelrhodopsin2 (ChR2) or control vector into the VTA resulting in the selective expression of these opsins in DA neurons. Then, we stimulated the VTA, NAc (core and shell) or mPFC (prelimbic cortex (PL) and infralimbic cortex (IL)) via an optical fiber. The mice with ChR2 learned instrumental responses corresponding to the delivery of photostimulation into the VTA. The projections to the NAc core and shell from the VTA and stimulation of the NAc subregion both induced reinforcement. For projections to the mPFC (IL and PL), we verified that stimulation of the IL induced reinforcement dependent on DA from the VTA but not the PL. Furthermore, micro-infusion of methamphetamine into the NAc core and NAc shell also induced hyper-locomotion in a dose-dependent manner with a slight tendency of increased excitation of the IL but not PL. Taken together, excitation of the projection into the NAc core, NAc shell and IL elicited positive behavior during reward.
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Affiliation(s)
- Xiao Han
- State Key Laboratory of Toxicology and Medical Countermeasures, Beijing Key Laboratory of Neuropsychopharmacology, Beijing Institute of Pharmacology and Toxicology, 27th Taiping Road, Beijing, 100850, China
| | - Man-Yi Jing
- State Key Laboratory of Toxicology and Medical Countermeasures, Beijing Key Laboratory of Neuropsychopharmacology, Beijing Institute of Pharmacology and Toxicology, 27th Taiping Road, Beijing, 100850, China
| | - Tai-Yun Zhao
- State Key Laboratory of Toxicology and Medical Countermeasures, Beijing Key Laboratory of Neuropsychopharmacology, Beijing Institute of Pharmacology and Toxicology, 27th Taiping Road, Beijing, 100850, China
| | - Ning Wu
- State Key Laboratory of Toxicology and Medical Countermeasures, Beijing Key Laboratory of Neuropsychopharmacology, Beijing Institute of Pharmacology and Toxicology, 27th Taiping Road, Beijing, 100850, China
| | - Rui Song
- State Key Laboratory of Toxicology and Medical Countermeasures, Beijing Key Laboratory of Neuropsychopharmacology, Beijing Institute of Pharmacology and Toxicology, 27th Taiping Road, Beijing, 100850, China.
| | - Jin Li
- State Key Laboratory of Toxicology and Medical Countermeasures, Beijing Key Laboratory of Neuropsychopharmacology, Beijing Institute of Pharmacology and Toxicology, 27th Taiping Road, Beijing, 100850, China.
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Camarini R, Pautassi RM. Behavioral sensitization to ethanol: Neural basis and factors that influence its acquisition and expression. Brain Res Bull 2016; 125:53-78. [PMID: 27093941 DOI: 10.1016/j.brainresbull.2016.04.006] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2015] [Revised: 04/07/2016] [Accepted: 04/08/2016] [Indexed: 12/29/2022]
Abstract
Ethanol-induced behavioral sensitization (EBS) was first described in 1980, approximately 10 years after the phenomenon was described for psychostimulants. Ethanol acts on γ-aminobutyric acid (GABA) and glutamate receptors as an allosteric agonist and antagonist, respectively, but it also affects many other molecular targets. The multiplicity of factors involved in the behavioral and neurochemical effects of ethanol and the ensuing complexity may explain much of the apparent disparate results, found across different labs, regarding ethanol-induced behavioral sensitization. Although the mesocorticolimbic dopamine system plays an important role in EBS, we provide evidence of the involvement of other neurotransmitter systems, mainly the glutamatergic, GABAergic, and opioidergic systems. This review also analyses the neural underpinnings (e.g., induction of cellular transcription factors such as cyclic adenosine monophosphate response element binding protein and growth factors, such as the brain-derived neurotrophic factor) and other factors that influence the phenomenon, including age, sex, dose, and protocols of drug administration. One of the reasons that make EBS an attractive phenomenon is the assumption, firmly based on empirical evidence, that EBS and addiction-related processes have common molecular and neural basis. Therefore, EBS has been used as a model of addiction processes. We discuss the association between different measures of ethanol-induced reward and EBS. Parallels between the pharmacological basis of EBS and acute motor effects of ethanol are also discussed.
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Affiliation(s)
- Rosana Camarini
- Departamento de Farmacologia, Instituto de Ciências Biomédicas, Universidade de São Paulo, SP, Brazil.
| | - Ricardo Marcos Pautassi
- Instituto de Investigaciones Médicas M. y M. Ferreyra, Córdoba (IMMF-CONICET-Universidad Nacional de Córdoba), Universidad Nacional de Córdoba, Argentina
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3
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El Hage C, Bédard AM, Samaha AN. Antipsychotic treatment leading to dopamine supersensitivity persistently alters nucleus accumbens function. Neuropharmacology 2015; 99:715-25. [DOI: 10.1016/j.neuropharm.2015.03.012] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2014] [Revised: 03/13/2015] [Accepted: 03/14/2015] [Indexed: 10/23/2022]
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Dela Peña I, Gevorkiana R, Shi WX. Psychostimulants affect dopamine transmission through both dopamine transporter-dependent and independent mechanisms. Eur J Pharmacol 2015; 764:562-570. [PMID: 26209364 PMCID: PMC4600454 DOI: 10.1016/j.ejphar.2015.07.044] [Citation(s) in RCA: 69] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2015] [Revised: 07/15/2015] [Accepted: 07/20/2015] [Indexed: 12/14/2022]
Abstract
The precise mechanisms by which cocaine and amphetamine-like psychostimulants exert their reinforcing effects are not yet fully defined. It is widely believed, however, that these drugs produce their effects by enhancing dopamine neurotransmission in the brain, especially in limbic areas such as the nucleus accumbens, by inducing dopamine transporter-mediated reverse transport and/or blocking dopamine reuptake though the dopamine transporter. Here, we present the evidence that aside from dopamine transporter, non-dopamine transporter-mediated mechanisms also participate in psychostimulant-induced dopamine release and contribute to the behavioral effects of these drugs, such as locomotor activation and reward. Accordingly, psychostimulants could increase norepinephrine release in the prefrontal cortex, the latter then alters the firing pattern of dopamine neurons resulting in changes in action potential-dependent dopamine release. These alterations would further affect the temporal pattern of dopamine release in the nucleus accumbens, thereby modifying information processing in that area. Hence, a synaptic input to a nucleus accumbens neuron may be enhanced or inhibited by dopamine depending on its temporal relationship to dopamine release. Specific temporal patterns of dopamine release may also be required for certain forms of synaptic plasticity in the nucleus accumbens. Together, these effects induced by psychostimulants, mediated through a non-dopamine transporter-mediated mechanism involving norepinephrine and the prefrontal cortex, may also contribute importantly to the reinforcing properties of these drugs.
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Affiliation(s)
- Ike Dela Peña
- Departments of Pharmaceutical and Administrative Sciences, Loma Linda University Schools of Pharmacy and Medicine, Loma Linda, CA 92350, USA.
| | - Ruzanna Gevorkiana
- Departments of Pharmaceutical and Administrative Sciences, Loma Linda University Schools of Pharmacy and Medicine, Loma Linda, CA 92350, USA
| | - Wei-Xing Shi
- Departments of Pharmaceutical and Administrative Sciences, Loma Linda University Schools of Pharmacy and Medicine, Loma Linda, CA 92350, USA; Basic Sciences, Loma Linda University Schools of Pharmacy and Medicine, Loma Linda, CA 92350, USA.
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5
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Nikulina EM, Johnston CE, Wang J, Hammer RP. Neurotrophins in the ventral tegmental area: Role in social stress, mood disorders and drug abuse. Neuroscience 2014; 282:122-38. [PMID: 24875178 DOI: 10.1016/j.neuroscience.2014.05.028] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2014] [Revised: 05/04/2014] [Accepted: 05/11/2014] [Indexed: 01/19/2023]
Abstract
This review discusses the impact of neurotrophins and other trophic factors, including fibroblast growth factor and glial cell line-derived neurotrophic factor, on mood disorders, weight regulation and drug abuse, with an emphasis on stress- and drug-induced changes in the ventral tegmental area (VTA). Neurotrophins, comprising nerve growth factor, brain-derived neurotrophic factor (BDNF), and neurotrophins 3 and 4/5 play important roles in neuronal plasticity and the development of different psychopathologies. In the VTA, most research has focused on the role of BDNF, because other neurotrophins are not found there in significant quantities. BDNF originating in the VTA provides trophic support to dopamine neurons. The diverse intracellular signaling pathways activated by BDNF may underlie precise physiological functions specific to the VTA. In general, VTA BDNF expression increases after psychostimulant exposures, and enhanced BDNF level in the VTA facilitates psychostimulant effects. The impact of VTA BDNF on the behavioral effects of psychostimulants relies primarily on its action within the mesocorticolimbic circuit. In the case of opiates, VTA BDNF expression and effects seem to be dependent on whether an animal is drug-naïve or has a history of drug use, only the latter of which is related to dopamine mechanisms. Social defeat stress that is continuous in mice or intermittent in rats increases VTA BDNF expression, and is associated with depressive and social avoidance behaviors. Intermittent social defeat stress induces persistent VTA BDNF expression that triggers psychostimulant cross-sensitization. Understanding the cellular and molecular substrates of neurotrophin effects may lead to novel therapeutic approaches for the prevention and treatment of substance use and mood disorders.
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Affiliation(s)
- E M Nikulina
- Department of Basic Medical Sciences, University of Arizona College of Medicine, Phoenix, AZ, USA.
| | - C E Johnston
- Department of Basic Medical Sciences, University of Arizona College of Medicine, Phoenix, AZ, USA; Interdisciplinary Neuroscience Program, Arizona State University, Tempe, AZ, USA
| | - J Wang
- Interdisciplinary Neuroscience Program, Arizona State University, Tempe, AZ, USA
| | - R P Hammer
- Department of Basic Medical Sciences, University of Arizona College of Medicine, Phoenix, AZ, USA; Interdisciplinary Neuroscience Program, Arizona State University, Tempe, AZ, USA; Department of Pharmacology and Department of Psychiatry, University of Arizona College of Medicine, Tucson, AZ, USA
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Mathews IZ, Brudzynski SM, McCormick CM. Heightened locomotor-activating effects of amphetamine administered into the nucleus accumbens in adolescent rats. Int J Dev Neurosci 2011; 29:501-7. [PMID: 21616135 DOI: 10.1016/j.ijdevneu.2011.05.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2011] [Revised: 05/09/2011] [Accepted: 05/11/2011] [Indexed: 10/18/2022] Open
Abstract
There is a shift in sensitivity to systemically administered psychostimulants in adolescence, as evidenced by less amphetamine-induced locomotor activity in adolescent compared to adult rodents. Locomotor activating effects of amphetamine are dependent on drug actions in the core of the nucleus accumbens (NAc), but the contribution of this region to age differences in amphetamine sensitivity has not been studied directly. In the present study, we investigated the development of the NAc using targeted injections of amphetamine (0, 3, or 6 μg/side) directly into the NAc core in early (postnatal day 30; P30) or late (P45) adolescence, or in adulthood (P75). Locomotor activity was recorded during two 1h sessions, 48 h apart. Amphetamine increased locomotor activity at all ages. P45 rats were more active than adults only at the 3 μg/side dose, but this difference was not significant when baseline activity was taken into account. In contrast, P30 rats were more active than adults at the 6 μg/side dose, indicating that the magnitude of the locomotor response is highest in early adolescence. Results of the present study are the first to directly show a developmental difference in the sensitivity of the NAc to amphetamine under conditions in which the influence of pharmacokinetic factors and regulatory brain regions is minimized.
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Affiliation(s)
- I Z Mathews
- Department of Psychology and Centre for Neuroscience, Brock University, St. Catharines, ON, Canada L2S 3A1.
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7
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Conditioned cues and the expression of stimulant sensitization in animals and humans. Neuropharmacology 2008; 56 Suppl 1:160-8. [PMID: 18657553 DOI: 10.1016/j.neuropharm.2008.06.070] [Citation(s) in RCA: 123] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2008] [Revised: 06/19/2008] [Accepted: 06/29/2008] [Indexed: 11/21/2022]
Abstract
Repeated intermittent exposure to psychostimulants can lead to long-lasting sensitization of the drugs' behavioral and biochemical effects. Such findings have figured importantly in recent theories of drug addiction proposing that sensitized nucleus accumbens (NAcc) dopamine (DA) overflow in particular acts in concert with other alterations in the neurochemistry of this nucleus to promote drug seeking and self-administration. Yet, experiments in rodents, non-human primates and humans have not always detected behavioral or biochemical sensitization following drug exposure, bringing into doubt the utility of this model. In an effort to reconcile apparent discrepancies in the literature, this review assesses conditions that might affect the expression of sensitization during testing. Specifically, the role played by conditioned cues is reviewed. A number of reports strongly support a potent and critical role for conditioned stimuli in the expression of sensitization. Findings suggest that stimuli associated either with the presence or absence of drug can respectively facilitate or inhibit sensitized responding. It is concluded that the presence or absence of such stimuli during testing for sensitization in animal and human studies could significantly affect the results obtained. It is necessary to consider this possibility especially when interpreting the results of studies that fail to observe sensitized responding.
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8
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Morris HV, Dawson GR, Reynolds DS, Atack JR, Rosahl TW, Stephens DN. Alpha2-containing GABA(A) receptors are involved in mediating stimulant effects of cocaine. Pharmacol Biochem Behav 2008; 90:9-18. [PMID: 18358520 DOI: 10.1016/j.pbb.2008.02.010] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/12/2007] [Revised: 01/29/2008] [Accepted: 02/06/2008] [Indexed: 10/22/2022]
Abstract
alpha2 subunit-containing GABA(A) receptors are involved in incentive learning associated with cocaine, and in cocaine addiction. Deletion of alpha2-containing receptors abolishes cocaine-induced behavioural sensitisation (BS), while selective activation of alpha2 receptors, achieved using Ro 15-4513's agonist properties in alpha2(H101R) mice, induced BS. Here, we investigate further the mechanisms underlying Ro 15-4513-induced behavioural sensitisation in alpha2(H101R) mice. alpha2(H101R) mice sensitised to Ro 15-4513 (10 mg/kg) showed an enhanced stimulant response to cocaine (10 mg/kg). In contrast, cocaine (10 mg/kg)-sensitised alpha2(H101R) mice did not show enhanced sensitivity to the stimulant effects of Ro 15-4513 (1, 3 and 10 mg/kg), suggesting that the neural adaptations underlying Ro 15-4513 induced BS are related to, but not identical with those associated with cocaine-induced plasticity. Secondly, we investigated whether alpha2-containing receptors are involved in mediating the ability of BZs to facilitate cocaine-induced activity. The non-selective (i.e., alpha1, alpha2, alpha3 and alpha5 subtype) benzodiazepine GABA(A) receptor agonist midazolam (10 and 30 mg/kg) potentiated cocaine (10 mg/kg) hyperactivity in wildtype mice, but not in alpha2(H101R) mice, in which alpha2-containing receptors are insensitive to benzodiazepines. To determine where alpha2 receptors are localised we compared BZ-insensitive sites between wildtype (alpha4 and alpha6) and alpha2(H101R) (alpha2, alpha4 and alpha6) mice, using quantitative autoradiography to estimate [(3)H]Ro 15-4513 binding in the presence of 10 muM diazepam. alpha2 receptors were found in projection areas of the mesolimbic dopamine pathway including accumbens, central amygdala, and basolateral amygdala as well as CA1 and CA3 areas of the hippocampus. The involvement of the alpha2-containing receptor in mediating BZ's potentiating effect on cocaine hyperactivity suggests that the locomotor stimulant effects of BZs and psychostimulants may be mediated by a common neural system, but the lack of cross sensitisation to Ro 15-4513 in cocaine-sensitised alpha2(H101R) mice, suggests that this form of BS may occur downstream of plastic events underlying cocaine sensitisation.
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Affiliation(s)
- H V Morris
- Department of Psychology, University of Sussex, Falmer, Brighton, BN1 9QG, UK
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Hyman SE, Malenka RC, Nestler EJ. Neural mechanisms of addiction: the role of reward-related learning and memory. Annu Rev Neurosci 2006; 29:565-98. [PMID: 16776597 DOI: 10.1146/annurev.neuro.29.051605.113009] [Citation(s) in RCA: 1805] [Impact Index Per Article: 100.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Addiction is a state of compulsive drug use; despite treatment and other attempts to control drug taking, addiction tends to persist. Clinical and laboratory observations have converged on the hypothesis that addiction represents the pathological usurpation of neural processes that normally serve reward-related learning. The major substrates of persistent compulsive drug use are hypothesized to be molecular and cellular mechanisms that underlie long-term associative memories in several forebrain circuits (involving the ventral and dorsal striatum and prefrontal cortex) that receive input from midbrain dopamine neurons. Here we review progress in identifying candidate mechanisms of addiction.
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Affiliation(s)
- Steven E Hyman
- Office of the Provost, Harvard University, Cambridge, Massachusetts 02138, USA.
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10
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Couceyro PR, Evans C, McKinzie A, Mitchell D, Dube M, Hagshenas L, White FJ, Douglass J, Richards WG, Bannon AW. Cocaine- and Amphetamine-Regulated Transcript (CART) Peptides Modulate the Locomotor and Motivational Properties of Psychostimulants. J Pharmacol Exp Ther 2005; 315:1091-100. [PMID: 16099925 DOI: 10.1124/jpet.105.091678] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Drug addiction results from a subversion of neural circuits that control motivation. Although the hedonic and addictive properties of psychostimulants and drugs of abuse are predominantly attributed to dopamine and glutamate, it is appreciated that other signaling molecules in the brain are important. This study suggests that cocaine- and amphetamine-regulated transcript (CART) peptides modulate the locomotor and motivational properties of psychostimulants. The behavioral effects of cocaine and amphetamine were examined in Carttm1Amgen knockout (Cart KO) and wild-type (WT) mice. Acute amphetamine administration increased in locomotor activity in WT mice, but this response was attenuated in Cart KO mice. Repeated amphetamine produced locomotor sensitization in WT mice but hardly any in Cart KO mice. Amphetamine elicited conditioned place preference in both genotypes, but amphetamine's potency was reduced in the Cart KO mice. Intravenous cocaine self-administration was observed in both genotypes, but Cart KO mice consumed less cocaine and responded less for cocaine than WT mice. The behavioral effects of psychostimulants were reduced in the mutant Cart KO mice. By contrast, open field activity and sucrose preference of drug-naive mice WT and Cart KO mice were not significantly different. The attenuated effects of amphetamine and cocaine in Cart KO mice suggest a positive neuromodulatory role for CART peptides in the locomotor and motivational properties of psychostimulants and implicate CART peptides in psychostimulant addiction.
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Affiliation(s)
- Pastor R Couceyro
- Department of Cellular and Molecular Pharmacology, Rosalind Franklin University of Medicine and Science/Chicago Medical School, North Chicago, IL 60064, USA.
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Kauer JA. Learning mechanisms in addiction: synaptic plasticity in the ventral tegmental area as a result of exposure to drugs of abuse. Annu Rev Physiol 2004; 66:447-75. [PMID: 14977410 DOI: 10.1146/annurev.physiol.66.032102.112534] [Citation(s) in RCA: 154] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
One of the central questions in neurobiology is how experience modifies neural function, and how changes in the nervous system permit an animal to adapt its behavior to a changing environment. Learning and adaptation to a host of different environmental stimuli exemplify processes we know must alter the nervous system because the behavioral output changes after experience. Alterations in behavior after exposure to addictive drugs are a striking example of chemical alterations of nervous system function producing long-lasting changes in behavior. The alterations produced in the central nervous system (CNS) by addictive drugs are of interest because of their relationship to human substance abuse but also because these CNS alterations produce dramatic, easily observed alterations in behavior in response to discrete stimuli. Considerable study has been given to behavioral and biochemical correlates of addiction over the past 50 or more years; however, our understanding of the cellular physiological responses of affected CNS neurons is in its infancy. This review focuses on alterations in cellular and synaptic physiology in the ventral tegmental area (VTA) in response to addictive drugs.
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Affiliation(s)
- Julie A Kauer
- Department of Pharmacology, Physiology and Biotechnology, Brown University, Providence, Rhode Island 02912, USA.
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Vezina P. Sensitization of midbrain dopamine neuron reactivity and the self-administration of psychomotor stimulant drugs. Neurosci Biobehav Rev 2004; 27:827-39. [PMID: 15019432 DOI: 10.1016/j.neubiorev.2003.11.001] [Citation(s) in RCA: 392] [Impact Index Per Article: 19.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Psychostimulant drugs like amphetamine are readily self-administered by humans and laboratory animals by virtue of their actions on dopamine (DA) neurons in the midbrain. Exposing animals to this drug either systemically or in the cell body region of these neurons in the ventral tegmental area leads to long-lasting alterations in dopaminergic function. These have most often been assessed as increased locomotor activity and enhanced DA overflow in the nucleus accumbens (NAcc) after re-exposure to the drug weeks to months later. Evidence is presented showing that manipulations that produce this sensitization of midbrain DA neuron reactivity enhance the pursuit and self-administration of psychostimulant drugs. Procedures known to prevent the induction of sensitization by amphetamine also prevent the facilitation of drug taking. Enhanced drug self-administration and primed reinstatement of drug seeking are also accompanied by enhanced NAcc DA reactivity. Finally, drugs that increase NAcc DA overflow acutely but fail to produce sensitization of this effect are not associated with the subsequent enhancement of self-administration. These results indicate a direct relationship between the sensitization of midbrain dopamine neuron reactivity and the excessive pursuit and self-administration of psychostimulant drugs. Understanding the neuronal events and adaptations that underlie the induction and expression of sensitization may thus help elucidate how drug abuse develops, how it is reinstated and ultimately how both may be prevented.
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Affiliation(s)
- Paul Vezina
- Department of Psychiatry, The University of Chicago, 5841 S Maryland Avenue, MC 3077, Chicago, IL 60637-1478, USA.
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Faleiro LJ, Jones S, Kauer JA. Rapid AMPAR/NMDAR response to amphetamine: a detectable increase in AMPAR/NMDAR ratios in the ventral tegmental area is detectable after amphetamine injection. Ann N Y Acad Sci 2004; 1003:391-4. [PMID: 14684469 DOI: 10.1196/annals.1300.032] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- L J Faleiro
- Department of Molecular Physiology, Pharmacology and Biotechnology, Brown University, Providence, Rhode Island 02912, USA
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14
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Beinfeld MC. What we know and what we need to know about the role of endogenous CCK in psychostimulant sensitization. Life Sci 2003; 73:643-54. [PMID: 12801586 DOI: 10.1016/s0024-3205(03)00384-9] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The unique distribution of CCK and its receptors and its co-localization with dopamine makes it ideally situated to pay a role in dopamine-mediated reward and psychostimulant sensitization. A number of studies support the hypothesis that CCK acting through the CCK 1 and CCK 2 receptors is an endogenous modulator of dopamine neurotransmission. Behavioral studies with CCK antagonists and CCK 1 receptor mutant rats support a role for endogenous CCK in behavioral sensitization to psychostimulants. CCK microdialysis studies in the nucleus accumbens (NAC) have demonstrated that extracellular CCK is increased in the NAC by psychostimulants, providing neurochemical evidence that CCK could be involved in the behavioral response to psychostimulants. A model for how CCK may be acting in multiple brain regions to foster sensitization is presented and the gaps in our knowledge about the role of CCK in psychostimulant sensitization are described.
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Affiliation(s)
- Margery C Beinfeld
- Department of Pharmacology and Experimental Therapeutics, Tufts University School of Medicine, 136 Harrison Ave., Boston, MA 02111, USA.
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Reid MS, Ho LB, Hsu K, Fox L, Tolliver BK, Adams JU, Franco A, Berger SP. Evidence for the involvement of cyclooxygenase activity in the development of cocaine sensitization. Pharmacol Biochem Behav 2002; 71:37-54. [PMID: 11812506 DOI: 10.1016/s0091-3057(01)00614-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Phospholipase A2 (PLA(2)) activation generates the release of arachidonic acid (AA) and platelet-activating factor (PAF), two compounds which may be involved in neuroplasticity. In previous studies, we found that PLA(2) activation is involved in the development of stimulant sensitization. In the present study, we have examined the roles of AA and PAF in the development of stimulant sensitization using agonists and antagonists selective for PAF receptors or the induction of various AA cascade-mediated eicosanoids. Sprague-Dawley rats were treated for 5 days with cocaine (30 mg/kg) or D-amphetamine (1 mg/kg) preceded 15 min earlier by various antagonists, and then tested following a 10-day withdrawal period for cocaine (15 mg/kg) or D-amphetamine (0.5 mg/kg)-induced locomotion. Consistent with our earlier work, pretreatment with the PLA(2) inhibitor quinacrine (25 mg/kg) blocked the development of cocaine and amphetamine sensitization. The lipoxygenase (LOX) inhibitors nordihydroguaiaretic acid (NDGA) (5-10 mg/kg) and MK-886 (1 mg/kg) had no effect on cocaine sensitization. The PAF receptor antagonist WEB 2086 (5-10 mg/kg) reduced the development of cocaine sensitization. The cyclooxygenase (COX) inhibitors indomethacin (1-2 mg/kg), piroxicam (0.5-1 mg/kg), 6-methoxy-2-napthylacetic acid (6-MNA; 0.5-1 mg/kg), and NS-398 (0.5-1 mg/kg) blocked the development of cocaine sensitization. The COX inhibitors indomethacin (2 mg/kg) and 6-MNA (1 mg/kg) also reduced the development of amphetamine sensitization. Rats were administered bilateral intraventral tegmental area (VTA) injections of D-amphetamine (5 microg/side) or saline coadministered with indomethacin (0.5 microg/side) or vehicle three times over 5 days and were then tested after a 10-day withdrawal for D-amphetamine (0.5 mg/kg ip)-induced locomotion. Intra-VTA amphetamine induced a robust form of amphetamine sensitization, which was blocked by coadministration of indomethacin. Unilateral intra-VTA injections of PAF (1 microg) did not significantly alter cocaine (15 mg/kg ip)-induced locomotion when tested after a 3-day withdrawal. These findings suggest that COX, and possibly PAF, activity is involved in the development of stimulant sensitization. Neuroanatomical studies demonstrate that this may occur at the level of the VTA.
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Affiliation(s)
- Malcolm S Reid
- Department of Psychiatry, New York University School of Medicine, Psychiatry Research 116A, New York Veterans Affairs Medical Center, 423 East 23rd Street, New York, NY 10010, USA.
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Pierce RC, Bari AA. The role of neurotrophic factors in psychostimulant-induced behavioral and neuronal plasticity. Rev Neurosci 2001; 12:95-110. [PMID: 11392459 DOI: 10.1515/revneuro.2001.12.2.95] [Citation(s) in RCA: 98] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Several neurotrophic factors influence the development, maintenance and survival of dopaminergic neurons in the mammalian central nervous system (CNS), including neurotrophin-3 (NT-3), brain derived neurotrophic factor (BDNF), ciliary neurotrophic factor (CNTF), basic fibroblast growth factor (bFGF) and glial derived neurotrophic factor (GDNF). This review focuses on the role of these neurotrophic factors in psychostimulant-induced behavioral sensitization, a form of dopamine-mediated neuronal plasticity that models aspects of paranoid schizophrenia as well as drug craving among psychostimulant addicts. Whereas NT-3, CNTF and bFGF appear to play a positive role in psychostimulant-induced behavioral sensitization, GDNF inhibits this form of behavioral plasticity. The role of BDNF in behavioral sensitization, however, remains elusive. While it has been shown that neurotrophic factors can influence the behavioral, structural and biochemical phenomena related to psychostimulant-induced neuronal plasticity, it is unclear which neurotrophic factors are important physiologically and which have purely pharmacological effects. In either case, examining the role of neurotrophic factors in behavioral sensitization may enhance our understanding of the mechanisms underlying the development of paranoid psychosis and drug craving and lead to the development of novel pharmacological treatments for these disorders.
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Affiliation(s)
- R C Pierce
- Department of Pharmacology, Boston University School of Medicine, MA 02118, USA.
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17
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Richtand NM, Woods SC, Berger SP, Strakowski SM. D3 dopamine receptor, behavioral sensitization, and psychosis. Neurosci Biobehav Rev 2001; 25:427-43. [PMID: 11566480 DOI: 10.1016/s0149-7634(01)00023-9] [Citation(s) in RCA: 115] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Behavioral sensitization is a progressive, enduring enhancement of behaviors that develops following repeated stimulant administration. It is mediated in part by dopaminergic pathways that also modulate a number of psychiatric conditions including the development of psychosis. We propose that down-regulation of D3 dopamine receptor function in critical brain regions contributes to sensitization. Rodent locomotion, a sensitizable behavior, is regulated by the opposing influence of dopamine receptor subtypes, with D3 stimulation opposing concurrent D1 and D2 receptor activation. The D3 dopamine receptor has a 70-fold greater affinity for dopamine than D1 or D2 dopamine receptors. This imbalance in ligand affinity dictates greater occupancy for D3 than D1 or D2 receptors at typical dopamine concentrations following stimulant drug administration, resulting in differences in the relative tolerance at D3 vs D1 and D2 receptors. Sensitization may therefore result in part from accommodation of the inhibitory D3 receptor 'brake' on D1/D2 mediated behaviors, leading to a progressive locomotion increase following repeated stimulant exposure. The requirement for differential tolerance at D3 vs D1 and D2 receptors may explain the observed development of sensitization following application of cocaine, but not amphetamine, directly into nucleus accumbens. If correct, the 'D3 Dopamine Receptor Hypothesis' suggests D3 antagonists could prevent sensitization, and may interrupt the development of psychosis when administered during the prodromal phase of psychotic illness. Additional study is needed to clarify the role of the D3 dopamine receptor in sensitization and psychosis.
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Affiliation(s)
- N M Richtand
- Department of Psychiatry, V-116A, Cincinnati Veterans Affairs Medical Center, 3200 Vine Street, Cincinnati, OH 45220, USA.
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Zhang Y, Loonam TM, Noailles PA, Angulo JA. Comparison of cocaine- and methamphetamine-evoked dopamine and glutamate overflow in somatodendritic and terminal field regions of the rat brain during acute, chronic, and early withdrawal conditions. Ann N Y Acad Sci 2001; 937:93-120. [PMID: 11458542 DOI: 10.1111/j.1749-6632.2001.tb03560.x] [Citation(s) in RCA: 104] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Methamphetamine and cocaine are among the most commonly abused psychostimulants. Repeated injections of psychostimulants produce behavioral sensitization or augmented locomotion in rats. Behavioral sensitization to methamphetamine and cocaine is long lasting and persists after cessation of drug treatment. Because dopamine and glutamate are major neurotransmitters of the neostriatum, we evaluated the profile of cocaine- or methamphetamine-evoked dopamine and glutamate overflow in the caudate putamen, nucleus accumbens, ventral tegmental area, and substantia nigra compacta of the rat brain. We also compared acute exposure to these drugs with chronic treatment and early withdrawal. Acute injection of methamphetamine (1 mg/kg of body weight) or cocaine (10 mg/kg) resulted in elevated levels of extracellular dopamine in all brain regions measured, although the magnitude of increase varied between brain regions. Overall, methamphetamine caused more dopamine to accumulate in the extracellular space than did cocaine when administered to animals during early withdrawal (7 days of daily injections and challenge on day 11). For example, a challenge injection of methamphetamine produced a greater elevation of extracellular dopamine in the caudate putamen when compared to acute (naïve) exposure. By contrast, a challenge injection of cocaine resulted in dopamine levels in the caudate putamen that were lower than those observed for acute exposure. In the ventral tegmental area and the substantia nigra compacta, a challenge injection of methamphetamine or cocaine resulted in extracellular dopamine levels that were lower than those for acute exposure. Thus, it appears that behavioral sensitization to cocaine can be sustained during early withdrawal in the absence of augmented drug-evoked dopamine overflow. Acute injection of methamphetamine or cocaine did not change extracellular levels of glutamate in the neostriatum. Cocaine challenge (early withdrawal) increased glutamate overflow in the caudate putamen and the nucleus accumbens. In contrast, methamphetamine challenge increased glutamate overflow in the caudate putamen, but it decreased glutamate in the nucleus accumbens. In the ventral tegmental area and the substantia nigra compacta, acute methamphetamine exposure decreased glutamate overflow, but acute cocaine exposure increased it. Although amphetamines and cocaine induce similar behavioral responses, the results presented here demonstrate that at the neurochemical level (neurotransmitter release) they sometimes evoke opposite effects depending on the brain region studied and the duration of drug treatment. Moreover, the sensitized augmentation of locomotor activity observed by us and others in response to a challenge injection of cocaine is not dependent on elevation of the extracellular concentration of dopamine in the neostriatum. We are currently investigating the hypothesis that cocaine activates peptidergic systems of the neostriatum and that these systems modulate the synaptic release of dopamine in response to psychostimulants.
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Affiliation(s)
- Y Zhang
- Department of Biological Sciences, Hunter College, City University of New York, 695 Park Avenue, New York, NY 10021, USA
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19
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Gong W, Neill DB, Lynn M, Justice JB. Dopamine D1/D2 agonists injected into nucleus accumbens and ventral pallidum differentially affect locomotor activity depending on site. Neuroscience 2001; 93:1349-58. [PMID: 10501459 DOI: 10.1016/s0306-4522(99)00235-3] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Ventral pallidal dopamine has been recently shown to play an important role in psychostimulant reward and locomotor activation. The aim of the present study was to compare the roles of ventral pallidal D1 and D2 receptors in evoking locomotor activity with those in the nucleus accumbens. The D1 agonist SKF 38393 and the D2 agonist quinpirole hydrochloride (0.3-3 microg/ 0.5 microl) were bilaterally injected into ventral pallidum or nucleus accumbens through pre-implanted cannulae. In the ventral pallidum, 0.3-1 microg SKF 38393 increased locomotor activity while 3 microg had no effect; 3 microg quinpirole suppressed locomotion while 0.3-1 microg had no effect. Locomotor activity induced by an equigram (0.3 microg) mixture of SKF 38393 and quinpirole, while significantly higher than that induced by 0.3 microg quinpirole was not significantly higher than that induced by 0.3 microg SKF 38393 alone. At the 3 microg dose, SKF 38393 injections into anterior ventral pallidum increased activity; injections into posterior ventral pallidum decreased activity. In the nucleus accumbens, 0.3-3 microg SKF 38393 dramatically increased locomotor activity while quinpirole moderately increased locomotion. In the group that had previously received the full quinpirole dose range, injection of the equigram (0.3 microg) mixture of SKF 38393 and quinpirole induced locomotor activation which was higher than that induced by either drug alone or by the addition of the effect of each drug alone, i.e. synergy occurred. Moreover, rats that had previously received SKF 38393 developed a sensitized locomotor response to subsequent SKF 38393, quinpirole or the mixture of these two drugs. The difference in locomotor response to dopamine agonists between the ventral pallidum and nucleus accumbens is consistent with electrophysiological evidence collected at these two sites. These findings suggest that, unlike the nucleus accumbens, where D1 and D2 receptor activation may facilitate each other to induce a synergistic effect on locomotor activity, ventral pallidal D1 and D2 receptors may be located on different neurons and coupled with different, if not opposite, behavioral output.
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MESH Headings
- 2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-benzazepine/pharmacology
- Animals
- Behavior, Animal/drug effects
- Dopamine Agonists/pharmacology
- Electrophysiology
- Globus Pallidus/chemistry
- Globus Pallidus/drug effects
- Locomotion/drug effects
- Male
- Microinjections
- Motor Activity/drug effects
- Nucleus Accumbens/chemistry
- Nucleus Accumbens/drug effects
- Quinpirole/pharmacology
- Rats
- Rats, Sprague-Dawley
- Receptors, Dopamine D1/agonists
- Receptors, Dopamine D1/physiology
- Receptors, Dopamine D2/agonists
- Receptors, Dopamine D2/physiology
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Affiliation(s)
- W Gong
- Department of Chemistry, Emory University, Atlanta, GA 30322, USA
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20
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Abstract
The prefrontal cortex (PFC) has long been known to be involved in the mediation of complex behavioral responses. Considerable research efforts are directed towards refining the knowledge about the function of this brain area and the role it plays in cognitive performance and behavioral output. In the first part, this review provides, from a pharmacological perspective, an overview of anatomical, electrophysiological and neurochemical aspects of the function of the PFC, with an emphasis on the mesocortical dopamine system. Anatomy of the mesocortical system, basic physiological and pharmacological properties of neurotransmission within the PFC, and interactions between dopamine and glutamate as well as other transmitters within the mesocorticolimbic circuit are included. The coverage of these data is largely restricted to what is relevant for the second part of the review which focuses on behavioral studies that have examined the role of the PFC in a variety of phenomena, behaviors and paradigms. These include reward and addiction, locomotor activity and sensitization, learning, cognition, and schizophrenia. Although the focus of this review is on the mesocortical dopamine system, given the intricate interactions of dopamine with other transmitter systems within the PFC and the importance of the PFC as a source of glutamate in subcortical areas, these aspects are also covered in some detail where appropriate. Naturally, a topic as complex as this cannot be covered comprehensively in its entirety. Therefore this review is largely limited to data derived from studies using rats, and it is also specifically restricted to data concerning the medial PFC (mPFC). Since in several fields of research the findings concerning the function or role of the mPFC are relatively inconsistent, the question is addressed whether these inconsistencies might, at least in part, be related to the anatomical and functional heterogeneity of this brain area.
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Affiliation(s)
- T M Tzschentke
- Grünenthal GmbH, Research and Development, Department of Pharmacology, Postfach 500444, 52088, Aachen, Germany.
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21
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King GR, Xiong Z, Douglass S, Ellinwood EH. Long-term blockade of the expression of cocaine sensitization by ondansetron, a 5-HT(3) receptor antagonist. Eur J Pharmacol 2000; 394:97-101. [PMID: 10771040 DOI: 10.1016/s0014-2999(99)00926-7] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
Intermittent cocaine administration induces sensitization (reverse tolerance) to its behavioral effects. The mechanism(s) mediating sensitization is not clear, however, previous research has implicated 5-HT(3) receptors in the expression of sensitization. The present experiment evaluated the ability of the 5-HT(3) receptor antagonist, ondansetron, administered during withdrawal from chronic intermittent cocaine administration, to block the expression of sensitization. Rats were pretreated for 14 days by daily subcutaneous injections of either 40 mg/kg cocaine or 0.9% saline. During the first 5 days of withdrawal from this pretreatment regimen, all rats received a daily subcutaneous injection of 0-1.0 mg/kg ondansetron. On days 7, 14 or 28 of withdrawal from the cocaine pretreatment, the rats received a 15.0-mg/kg cocaine challenge. Ambulatory behavior was automatically recorded for 60 min. Ondansetron had no significant effect on the subsequent behavioral response to cocaine in the saline control subjects. In contrast, daily injections of ondansetron blocked the expression of sensitization at all withdrawal times. We thus report that it is possible to permanently block the expression of sensitization once it has developed by administering a 5-HT(3) receptor antagonist.
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Affiliation(s)
- G R King
- Department of Psychiatry, Duke University Medical Center, Durham, NC 27710, USA.
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22
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Affiliation(s)
- J D Berke
- Secton on Molecular Plasticity, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland 20892, USA
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23
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West CH, Boss-Williams KA, Weiss JM. Motor activation by amphetamine infusion into nucleus accumbens core and shell subregions of rats differentially sensitive to dopaminergic drugs. Behav Brain Res 1999; 98:155-65. [PMID: 10210531 DOI: 10.1016/s0166-4328(98)00064-3] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Selective breeding based on activity in a swim test has been used to produce lines of rats that show a high level of activity in the swim test (Swim High-active (SwHi) rats) and a low level of activity in the swim test (Swim Low-active (SwLo) rats). Previous studies have indicated that dopamine (DA) function is enhanced in SwHi rats and reduced in SwLo rats; a principal finding was that SwLo rats showed much smaller increases in ambulatory activity after systemic administration of amphetamine than did SwHi or non-selected rats. In light of the importance of the nucleus accumbens (NAC) in amphetamine-induced activity, the present study investigated whether DA function in NAC differs in SwHi and SwLo rats. Amphetamine was infused bilaterally into either the core or shell subregion of NAC, and ambulation or swim test activity was then measured. In SwLo rats, infusion of amphetamine (0.2-2.0 microg) into either NAC core or shell produced moderate increases in ambulation. In SwHi rats, infusion of amphetamine into NAC shell produced similar moderate increases in ambulation, but infusion into the core produced markedly larger dose-related increases in ambulation. In the swim test, infusion of amphetamine (1.0 microg) increased activity by affecting the dominant behavior of each line; i.e. struggling increased in SwHi rats and floating decreased in SwLo rats, with large effects seen in both lines with infusion into either NAC core or shell. These results support the idea that the distinct behavioral characteristics of SwHi and SwLo rats are mediated in part by differences in NAC-DA function.
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Affiliation(s)
- C H West
- Department of Psychiatry and Behavioral Sciences, Emory University School of Medicine, Atlanta, GA 30322, USA.
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24
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Steketee JD. Repeated injection of GBR 12909, but not cocaine or WIN 35,065-2, into the ventral tegmental area induces behavioral sensitization. Behav Brain Res 1998; 97:39-48. [PMID: 9867229 DOI: 10.1016/s0166-4328(98)00016-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
A role for the mesolimbic dopamine system in the development of behavioral sensitization to psychostimulants, such as cocaine and amphetamine, is well established. Previous reports have suggested that the ventral tegmental area (VTA) is involved in the initiation of, while the nucleus accumbens is in involved in the expression of behavioral sensitization. This hypothesis is supported in part, by studies which demonstrated that behavioral sensitization could be induced by repeated intra-VTA, but not intra-accumbal, administration of amphetamine. The present studies were designed to determine whether repeated intra-VTA cocaine would similarly induce behavioral sensitization. Rats receiving four daily injections of cocaine (1.5, 5 or 15 nmol/side) into the VTA did not show a sensitized behavioral response when challenged with cocaine (15 mg/kg, ip) 1 week later. In contrast to this, repeated injection of the specific dopamine reuptake inhibitor, GBR 12909 (15 nmol/side) produced behavioral sensitization to a challenge injection of cocaine. Repeated injections of the cocaine analog WIN 35,065-2 did not induce behavioral sensitization to cocaine, suggesting that the local anesthetic properties of cocaine were not responsible for the inability of intra-VTA cocaine to induce sensitization. In summary, the data suggest that sensitization to cocaine may involve mechanisms different from amphetamine.
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Affiliation(s)
- J D Steketee
- Department of Pharmacology and Therapeutics, Louisiana State University Medical Center, Shreveport 71130-3932, USA.
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25
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Ben-Shahar O, Ettenberg A. Amphetamine infusions into the prefrontal cortex attenuate the sensitization to amphetamine. Prog Neuropsychopharmacol Biol Psychiatry 1998; 22:763-73. [PMID: 9723118 DOI: 10.1016/s0278-5846(98)00038-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
1. Adult male rats were implanted with chronic medial prefrontal cortex cannulae. 2. On each of 5 consecutive days, rats received bilateral 0.5 ml intra-prefrontal cortex injections of either 5 mg d-amphetamine or saline, followed by a subcutaneous injection of either 1 mg/kg d-amphetamine or saline. 3. Immediately after the drug treatments each rat was placed into a photocell equipped locomotor activity chamber for 60 min. 4. Administration of d-amphetamine into the prefrontal cortex did not block the acute locomotor response to subcutaneous d-amphetamine nor did it in itself produce an increase in locomotor activity. However, prefrontal cortex amphetamine treatments did attenuate the sensitized locomotor effects of subcutaneous amphetamine that developed over trials/days. 5. Dopamine in the prefrontal cortex may be involved in the development of amphetamine-induced behavioral sensitization.
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Affiliation(s)
- O Ben-Shahar
- Department of Psychology, University of California, Santa Barbara, USA
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26
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Pinheiro Carrera M, Brunhara FC, Schwarting RK, Tomaz C. Drug conditioning induced by intrastriatal apomorphine administration. Brain Res 1998; 790:60-6. [PMID: 9593824 DOI: 10.1016/s0006-8993(98)00047-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The present study examined (1) whether the neostriatum is involved in a drug-induced conditioned locomotor response and; (2) whether this structure participates in the development of behavioral sensitization. Moreover, the present study addressed the question whether the development of behavioral sensitization is necessary for the induction of conditioning. Rats received injections of either apomorphine (2 microg) or vehicle (solution of 0.1% ascorbate/saline) into the dorsal neostriatum daily for 7 days. These treatments were performed immediately prior to (apomorphine-paired group and vehicle group) or 30 min following (apomorphine-unpaired group) 10-min placement in an open field which served as the test environment. After a 3-day drug withdrawal period, the animals were given a 10-min non-drug vehicle test trial in the test environment. Three days later, a drug test with apomorphine was administered to the animals of the paired and unpaired treatment groups; the vehicle group again received an injection of vehicle. The analysis of locomotor activity in the open field (measured as the distance traversed) revealed that locomotor activity in the apomorphine-paired group was higher than in the other groups. There were no indications for behavioral sensitization to intrastriatal apomorphine, since the locomotor response in the apomorphine-paired group did not increase, but rather decreased with daily repeated injections of apomorphine. Furthermore, only the apomorphine-paired animals showed a higher locomotor response when tested after an intrastriatal injection of vehicle in the previously apomorphine-paired environment, which is indicative of a conditioned drug effect. These results suggest that the neostriatum is directly involved in the development of drug-induced conditioning of locomotor behavior but not in the establishment of behavioral sensitization.
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Affiliation(s)
- M Pinheiro Carrera
- Laboratory of Psychobiology and Center for Neuroscience and Behavior, University of São Paulo, FFCL-RP, Ribeirão Preto, SP, Brazil
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27
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CLARK DAVID, OVERTON PAULG. Alterations in excitatory amino acid-mediated regulation of midbrain dopaminergic neurones induced by chronic psychostimulant administration and stress: relevance to behavioural sensitization and drug addiction. Addict Biol 1998; 3:109-35. [PMID: 26734818 DOI: 10.1080/13556219872191] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
Repeated, intermittent administration of the psychostimulants d-amphetamine and cocaine, as well as other drugs of abuse, leads to an enduring augmentation of certain behavioural responses (e.g. locomotor activity) produced by these drugs. This behavioural sensitization has been the subject of considerable interest due to its potential relevance to drug addiction. Repeated administration of d-amphetamine also leads to an enhancement in the ability of electrical stimulation of the prefrontal cortex to induce burst firing in midbrain dopaminergic (DA) neurones. This hyper-responsiveness probably reflects a potentiation of transmission at excitatory amino acid (EAA)ergic synapses on DA neurones. In addition, we have previously reported that selective activation of mineralocorticoid receptors (MRs) by corticosterone leads to a potentiation of EAA-induced burst firing in midbrain DA neurones, an effect antagonized by glucocorticoid receptor (GR) activation. In this review article, we propose a model describing how drugs of abuse and stress alter EAA function at the level of DA cells in the ventral tegmental area (VTA), which can result in a long-lasting impact on behaviour. D-amphetamine produces a transitory increase in EAA-mediated transmission at the level of DA cells in the VTA, which triggers a more long-lasting change in EAAergic function resembling hippocampal long-term potentiation. Dopaminergic burst events are likely to be a critical link between enhanced EAAergic activity in afferents synapsing on DA neurones and plasticity at these synapses, by increasing calcium transport into the cell, which is known to be an important factor in synaptic plasticity. Selective MR occupation by corticosterone in the VTA facilitates the development of this plasticity. However, we hypothesize that during stress, GR-occupation also activates EAAergic afferents to DA neurones in a manner similar to that following psychostimulants. Under these circumstances, GR-occupation acts via circuitry external to the VTA, which may include the hippocampus. Thus, potentiation of EAAergic synapses on DA neurones in the VTA may represent a final common pathway by which two divserse means (psychostimulants and stress) achieve the same end (sensitization). Alterations in EAA-mediated transmission at the level of DA cells not only plays a critical role in the induction of behavioural sensitization, but probably continues to produce abnormal DA cell responses in the drug-free situation.
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28
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Abstract
Behavioral sensitization refers to the progressive augmentation of behavioral responses to psychomotor stimulants that develops during their repeated administration and persists even after long periods of withdrawal. It provides an animal model for the intensification of drug craving believed to underlie addiction in humans. Mechanistic similarities between sensitization and other forms of neuronal plasticity were first suggested on the basis of the ability of N-methyl-D-aspartate (NMDA) receptor antagonists to prevent the development of sensitization [Karler, R., Calder, L. D., Chaudhry, I. A. and Turkanis, S. A. (1989) Blockade of "reverse tolerance" to cocaine and amphetamine by MK-801. Life Sci., 45, 599-606]. This article will review the large number of subsequent studies addressing: (1) the roles of NMDA, alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionate (AMPA) and metabotropic glutamate receptors in the development and expression of behavioral sensitization, (2) excitatory amino acids (EAAs) and the role of conditioning in sensitization, (3) controversies regarding EAA involvement in behavioral sensitization based on studies with MK-801, (4) the effects of acute and repeated stimulant administration on EAA neurochemistry and EAA receptor expression, and (5) the neuroanatomy of EAA involvement in sensitization. To summarize, NMDA, AMPA metabotropic glutamate receptors all participate in the development of sensitization, while maintenance of the sensitized state involves alterations in neurochemical measures of EAA transmission as well as in the expression and sensitivity of AMPA and NMDA receptors. While behavioral sensitization likely involves complex neuronal circuits, with EAAs participating at several points within this circuitry, EAA projections originating in prefrontal cortex may play a particularly important role in the development of sensitization, perhaps via their regulatory effects on midbrain dopamine neurons. The review concludes by critically evaluating various hypotheses to account for EAA involvement in the development of behavioral sensitization, and considering the question of whether EAA receptors are involved in mediating the rewarding effects of psychomotor stimulants and sensitization of such rewarding effects.
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Affiliation(s)
- M E Wolf
- Department of Neuroscience, Finch University of Health Sciences/The Chicago Medical School, North Chicago, Il 60064-3095, USA. ,edu
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29
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Karler R, Bedingfield JB, Thai DK, Calder LD. The role of the frontal cortex in the mouse in behavioral sensitization to amphetamine. Brain Res 1997; 757:228-35. [PMID: 9200751 DOI: 10.1016/s0006-8993(97)00221-7] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Pharmacological studies have shown that a variety of neuroeffectors are involved in behavioral sensitization to amphetamine-induced stereotypy. In the present work, the effect of some of these drugs on sensitization was studied after intracortical administration in order to determine the role of the cortex in mediating their systemic effects. The dopamine antagonists sulpiride and spiperone were both ineffective against the acute response to amphetamine; nevertheless, both blocked the induction of sensitization, suggesting that the mesocortical dopamine pathway is not involved in the acute response but is necessary for the induction of sensitization. Both CPP, an NMDA receptor antagonist, and THIP, a GABA(A) agonist, blocked the acute response and the induction of sensitization to amphetamine. On the other hand, mecamylamine, the nicotinic cholinergic antagonist, failed to affect either the acute response or the induction of sensitization, which suggests that the cortex is not a locus of its activity. Anisomycin, an inhibitor of protein synthesis, and diltiazem, a calcium-channel blocker, were both ineffective against the acute response, but both blocked induction. All of the drugs, except CPP and THIP, were ineffective against the expression of sensitization; therefore, the ability of the other drugs to block expression must reside within another locus. Bicuculline injected intracortically in non-convulsant doses produced a stereotypy indistinguishable from that induced by amphetamine; and the effect was readily antagonized by CPP administered either systemically or intracortically. In contrast, sulpiride by either route of administration failed to block the bicuculline-induced stereotypy; we conclude, therefore, that the stereotypic effect of bicuculline is not mediated by dopamine. These results imply that amphetamine-induced stereotypy is mediated in the cortex by the removal of the inhibitory control of the excitatory system. The data also suggest that cortical dopamine, as well as the NMDA and GABA(A) systems, is important in sensitization to amphetamine. In general the data demonstrate that different neuroeffectors involved in sensitization exert their effects at different brain loci.
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Affiliation(s)
- R Karler
- Department of Pharmacology, University of Utah School of Medicine, Salt Lake City 84132, USA.
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30
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Tolerance and Sensitization to Opiates: Relationship to Withdrawal. NEUROSCIENCE INTELLIGENCE UNIT 1996. [DOI: 10.1007/978-3-662-22218-8_6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
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31
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Wolf ME, Dahlin SL, Hu XT, Xue CJ, White K. Effects of lesions of prefrontal cortex, amygdala, or fornix on behavioral sensitization to amphetamine: comparison with N-methyl-D-aspartate antagonists. Neuroscience 1995; 69:417-39. [PMID: 8552239 DOI: 10.1016/0306-4522(95)00248-h] [Citation(s) in RCA: 193] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Behavioral sensitization to amphetamine involves the mesoaccumbens dopamine system and is accompanied by cellular changes in this system. Excitatory amino acid antagonists, when co-administered with amphetamine, prevent both behavioral sensitization and associated changes in the mesoaccumbens dopamine system. This suggests that excitatory amino acid-dependent events are critical to the initiation of sensitization. This study sought to identify excitatory amino acid projections required for sensitization, focusing on projections to the nucleus accumbens or ventral tegmental area. The major excitatory projections to the nucleus accumbens originate in the prefrontal cortex, amygdala and hippocampus. The prefrontal cortex and amygdala also send excitatory projections to the ventral tegmental area. Ibotenic acid lesions of the prefrontal cortex or amygdala and electrolytic lesions of the fornix were performed in rats. After one week of recovery, rats were treated with water or 2.5 mg/kg amphetamine for six days and challenged with amphetamine on day 8. Activity was tested in photobeam cages on days 1 and 8. On day 1, control and sham-lesioned rats exhibited stereotyped behaviors followed by a period of post-stereotypy locomotion. On day 8, sensitization was evident as an enhancement of both stereotypy and post-stereotypy locomotion. Co-administration of N-methyl-D-aspartate antagonists [MK-801 (dizocilpine maleate) or CGS 19755] with amphetamine prevented the development of sensitization of both stereotypy and post-stereotypy locomotion. Neither antagonist, however, prevented the expression of sensitization. None of the lesions completely mimicked these effects of N-methyl-D-aspartate antagonists. Lesions of hippocampal projections traveling in the fornix produced a general disinhibition of locomotor activity, but did not prevent sensitization of either stereotypy or post-stereotypy locomotion. Lesions of the prefrontal cortex failed to prevent sensitization of stereotypy was obtained following repeated amphetamine administration. However, like prefrontal cortical lesions, amygdala lesions prevented sensitization of post-stereotypy locomotion. When interpreted in the light of previous studies demonstrating the importance of the ventral tegmental area in the initiation of sensitization, the present results suggest a likely role for neuronal circuits involving the prefrontal cortex, amygdala and ventral tegmental area in the development of sensitization of post-stereotypy locomotion following repeated amphetamine administration. Such circuits may initiate sensitization through a mechanism involving excitatory amino acid regulation of the activity of mesoaccumbens dopamine neurons. Parallel circuits, involving other brain regions, may similarly contribute to sensitization of stereotyped behaviors.
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Affiliation(s)
- M E Wolf
- Department of Neuroscience, Finch University of Health Sciences/The Chicago Medical School, IL 60064-3095, USA
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Morrow BA, Taylor JR, Roth RH. Prior exposure to cocaine diminishes behavioral and biochemical responses to aversive conditioning: reversal by glycine/N-methyl-D-aspartate antagonist co-treatment. Neuroscience 1995; 69:233-40. [PMID: 8637621 DOI: 10.1016/0306-4522(95)00184-k] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Animals will respond with stress-like behavioral and biochemical changes when exposed to a neutral stimulus that had previously been paired with a stressful stimulus. This phenomenon is generally known as aversive conditioning or conditioned fear. We tested the effect of prior exposure to cocaine on rats subjected to an aversive conditioning paradigm. Rats were given repeated doses of cocaine to develop a reverse tolerance or sensitization to the locomotor stimulant properties of cocaine. We blocked this sensitization to cocaine in one cocaine-exposed group by co-administering an antagonist of the strychinine-insensitive glycine site of the N-methyl-D-aspartate receptor complex, R-(+)-HA-966, which prevented the development of locomotor sensitization to cocaine. After about three weeks, we examined the effect of cocaine sensitization and the prevention of sensitization by R-(+)-HA-966 on aversive conditioning. Rats were exposed to 10 tones (neutral stimuli) paired with footshock (stressful stimuli) over 30 min for the conditioning session. The following day, rts were returned to the cages, received 10 tones only over 30 min and were killed. No drugs were given to any rat before either session and control rats received the tones without footshock in both sessions. Prior exposure to cocaine caused an attenuation of the behavioral effects of aversive conditioning, namely the amount of time spent immobilized and the number of fecal boli expelled. Additionally, the elevated metabolic activity of dopamine in the medial prefrontal cortex, nucleus accumbens and ventral tegmental area associated with aversive conditioning was diminished in rats pre-exposed to cocaine. The behavioral and biochemical effects of pre-exposure to cocaine were reversed in rats that receive R-(+)-HA-966 co-treatment with the five day cocaine sensitization regimen. These data suggest that prior behavioral sensitization to cocaine diminishes the stressful effect of conditioned fear and that these effects are reversed when sensitization is prevented with R-(+)-HA-966.
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Affiliation(s)
- B A Morrow
- Department of Pharmacology, Yale University School of Medicine, New Haven, CT 06520-8066, USA
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Abstract
Drugs of abuse share with conventional reinforcers the activation of specific neural pathways in the CNS that are the substrate of their motivational properties. Dopamine is recognized as the transmitter of one such neural pathway, being involved in at least three major aspects of motivation: modulation of motivational state, acquisition (incentive learning) and expression of incentive properties by motivational stimuli. Drugs of abuse of different pharmacological classes stimulate in the low dose range dopamine transmission particularly in the ventral striatum. Apart from psychostimulants, the evidence that stimulation of dopamine transmission by drugs of abuse provides the primary motivational stimulus for drug self-administration is either unconvincing or negative. However, stimulation of dopamine transmission is essential for the activational properties of drugs of abuse and might be instrumental for the acquisition of responding to drug-related incentive stimuli (incentive learning). Dopamine is involved in the induction and in the expression of behavioural sensitization by repeated exposure to various drugs of abuse. Sensitization to the dopamine-stimulant properties of specific drug classes leading to facilitation of incentive learning of drug-related stimuli might account for the strong control over behaviour exerted by these stimuli in the addiction state. Withdrawal from drugs of abuse results in a reduction in basal dopamine transmission in vivo and in reduced responding for conventional reinforcers. Although these changes are likely to be the expression of a state of dependence of the dopamine system their contribution to the motivational state of drug addiction is unclear.
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Affiliation(s)
- G Di Chiara
- Department of Toxicology, University of Cagliari, Italy
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Cador M, Bjijou Y, Stinus L. Evidence of a complete independence of the neurobiological substrates for the induction and expression of behavioral sensitization to amphetamine. Neuroscience 1995; 65:385-95. [PMID: 7777156 DOI: 10.1016/0306-4522(94)00524-9] [Citation(s) in RCA: 214] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The repeated administration of amphetamine in rats produces behavioral sensitization which is characterized either by a progressive enhancement of the locomotor activity induced by the drug or by an enduring behavioral hypersensitivity to the drug after the cessation of the treatment. Some authors have suggested that the action of amphetamine at the level of the nucleus accumbens is responsible for the expression of behavioral sensitization, whereas the action of amphetamine at the level of the dopamine cell bodies in the ventral tegmental area induces some changes responsible for the initiation of the phenomenon. The present study fully tested this hypothesis. In two separate experiments, the effects of different doses of amphetamine repeatedly administered in the ventral tegmental area or in the nucleus accumbens were tested on the later behavioral reactivity to the administration of amphetamine in the nucleus accumbens. Independent groups of rats received five repeated administrations (one injection every other day) of different doses of amphetamine either in the ventral tegmental area (0, 1, 2.5, 5 micrograms/0.5 microliters per side) or in the nucleus accumbens (0, 1, 3, 10 micrograms/l microliters per side). Two days following the last intracerebral amphetamine injection, each group received a phosphate buffer solution challenge directly into the nucleus accumbens followed two days later by an amphetamine challenge (1 microgram/l microliters per side) in the nucleus accumbens and two days later by a peripheral challenge with amphetamine (0.5 mg/kg, s.c.). Locomotor responses were recorded following each injection. Results showed that injections of amphetamine into the nucleus accumbens induced a dose-dependent increase in locomotor activity which remained identical with the repetition of the injections. No difference between the different intra-accumbens pretreated groups was observed following the diverse phosphate-buffered saline solution and amphetamine challenges. In contrast, intra-ventral tegmental area administration of amphetamine did not produce any modification of locomotor activity. However, whereas no difference between the differently pretreated groups was observed following phosphate-buffered saline administration into the nucleus accumbens, a potentiation of the locomotor response to a challenge dose of amphetamine into the nucleus accumbens was observed which was dependent on the dose of amphetamine pretreatment into the ventral tegmental area. Similar potentiation was observed following peripheral challenge with amphetamine. Finally, cross-sensitization was observed when a challenge dose of cocaine (10 micrograms/1 microliter per side) was injected into the nucleus accumbens, as well as when a peripheral challenge dose of morphine (2.5 mg/kg, s.c.) was administered to the ventral tegmental area-pretreated groups.(ABSTRACT TRUNCATED AT 400 WORDS)
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Affiliation(s)
- M Cador
- Unité INSERM 259, Université de Bordeaux II, France
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35
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Morrow BA, Taylor JR, Roth RH. R-(+)-HA-966, an antagonist for the glycine/NMDA receptor, prevents locomotor sensitization to repeated cocaine exposures. Brain Res 1995; 673:165-9. [PMID: 7757472 DOI: 10.1016/0006-8993(94)01456-r] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Repeated administration of cocaine results in a reverse tolerance or sensitization to the locomotor stimulant properties of cocaine. In this study, we examined the effect of an antagonist for the strychinine-insensitive glycine receptor of the NMDA receptor complex, R-(+)-HA-966, on the development of locomotor sensitization to cocaine. Co-administration of R-(+)-HA-966 with repeated cocaine prevented locomotor sensitization to a subsequent challenge dose of cocaine. However, R-(+)-HA-966 (15 mg/kg i.p.) did not attenuate locomotor activation to an acute dose of cocaine (15 mg/kg). These results indicate that the glycine/NMDA receptor is involved in locomotor sensitization to repeated cocaine administration but not in the locomotor activation to the acute stimulant effects of cocaine administration.
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Affiliation(s)
- B A Morrow
- Department of Pharmacology, Yale University School of Medicine, New Haven, CT 06520-8066, USA
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36
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Wolf ME, Xue CJ, White FJ, Dahlin SL. MK-801 does not prevent acute stimulatory effects of amphetamine or cocaine on locomotor activity or extracellular dopamine levels in rat nucleus accumbens. Brain Res 1994; 666:223-31. [PMID: 7882032 DOI: 10.1016/0006-8993(94)90776-5] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Recent work has shown that the development of behavioral sensitization to cocaine, amphetamine, and morphine is prevented by coadministration of N-methyl-D-aspartate (NMDA) antagonists such as MK-801. This suggests that NMDA receptors mediate long-term changes in neuronal responsiveness essential for the development of behavioral sensitization, similar to their role in other forms of neuronal plasticity. However, other studies, suggesting that NMDA receptor antagonists interfere with acute behavioral effects of psychomotor stimulants, call this interpretation into question and suggest that the ability of NMDA antagonists to prevent sensitization may reflect blockade of the acute effects of psychomotor stimulants. To examine this issue, behavioral and microdialysis studies assessed the effect of pretreatment with 0.1 mg/kg MK-801 on the ability of amphetamine and cocaine to stimulate locomotor activity and elevate extracellular dopamine (DA) levels in nucleus accumbens; this dose of MK-801 prevents sensitization when coadministered repeatedly with these stimulants. MK-801 pretreatment enhanced amphetamine-stimulated horizontal locomotion and stereotyped behavior. MK-801 pretreatment produced a modest attenuation of cocaine-stimulated horizontal locomotion, which may have reflected enhancement by MK-801 of certain components of cocaine-stimulated stereotypy. There was no effect of MK-801 pretreatment on the ability of amphetamine or cocaine to elevate extracellular DA levels in nucleus accumbens. These results suggest that the acute effects of cocaine and amphetamine on locomotor activity and extracellular DA levels are not prevented by MK-801, and that MK-801 must act through other mechanisms to prevent the development of behavioral sensitization.
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Affiliation(s)
- M E Wolf
- Department of Neuroscience, Finch University of Health Sciences, Chicago Medical School, IL 60064
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37
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Ben-Shahar O, Ettenberg A. Repeated stimulation of the ventral tegmental area sensitizes the hyperlocomotor response to amphetamine. Pharmacol Biochem Behav 1994; 48:1005-9. [PMID: 7972277 DOI: 10.1016/0091-3057(94)90212-7] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The locomotor-activating effects of amphetamine have been reported to increase with repeated drug administration. Although the precise underlying mechanisms for this behavioral sensitization effect remain unknown, many investigators have suggested a role for the mesolimbic dopaminergic system that emanates from cell bodies in the ventral tegmental area (VTA) of the midbrain. To test this hypothesis, the present study examined the effects of repeated electrical stimulation of the VTA (in place of repeated amphetamine administration) on the hyperlocomotor actions of d-amphetamine. Locomotor activity induced by 0.75 mg/kg SC amphetamine was assessed during two 90-min tests, one before and one after a 14-day treatment regimen during which animals experienced daily 15-min sessions of intracranial VTA stimulation. Each session involved the delivery of 600 trains of 0.5 s 60-Hz sine-wave stimulation applied at one of four intensities: 0, 15, 30, or 45 microA. An additional comparison group of rats self-administered 30 microA of VTA stimulation. Data analysis revealed that both the self-stimulation and the high current groups were reliably more active posttreatment compared to pretreatment. No such sensitization-like effects were observed in any of the other treatment groups. These results are consistent with the hypothesis that repeated activation of VTA neurons can produce a sensitization to the behavioral effects of d-amphetamine.
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Affiliation(s)
- O Ben-Shahar
- Department of Psychology, University of California, Santa Barbara 93106
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38
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Wise RA, Carlezon WA. Attenuation of the locomotor-sensitizing effects of the D2 dopamine agonist bromocriptine by either the D1 antagonist SCH 23390 or the D2 antagonist raclopride. Synapse 1994; 17:155-9. [PMID: 7974197 DOI: 10.1002/syn.890170303] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Injections of the selective D2 dopamine agonist bromocriptine (5.0 mg/kg, IP) produced progressively stronger locomotion over 10 days of repeated testing. Concurrent treatment with either the D1 antagonist SCH 23390 (0.01 or 0.1 mg/kg, IP) or the D2 antagonist raclopride (0.1 or 1.0 mg/kg, IP) suppressed bromocriptine-induced locomotion on treatment days and attenuated or blocked the progressive increases in locomotion that accompanied repeated injections of bromocriptine alone. The fact that D1 and D2 antagonists each block the acute actions of bromocriptine and attenuate the development of bromocriptine sensitization is suggested to imply a striatal rather than a ventral tegmental mechanism for the sensitization produced by repeated treatments with direct dopamine agonists.
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Affiliation(s)
- R A Wise
- Department of Psychology, Concordia University, Montreal, Canada
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39
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Steketee JD. Injection of the protein kinase inhibitor H7 into the A10 dopamine region blocks the acute responses to cocaine: behavioral and in vivo microdialysis studies. Neuropharmacology 1993; 32:1289-97. [PMID: 8152520 DOI: 10.1016/0028-3908(93)90023-v] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Cocaine produces a motor-stimulant response in part by its actions within the mesolimbic dopamine system. Repeated exposure to cocaine induces an augmented motor activity response which is termed behavioral sensitization, or reverse tolerance. Previous studies have suggested that sensitization may result from increased dopamine neuronal activity in the A10 region; the origin of the mesolimbic dopamine system. However, the exact mechanisms involved in the development of behavioral sensitization remain to be elucidated. Studies on other forms of sensitization in the nervous system suggest a critical role for increased protein kinase C (PKC) activity in the development of the sensitized response. As a first step in examining the role of PKC in cocaine-induced behavioral sensitization, the effect of intra-A10 administration of a PKC inhibitor, H7, on the acute motor-stimulant response to cocaine was studied. Intra-A10 injections of H7 dose-dependently (1.0-30.0 nmol/side) inhibited cocaine (15.0 mg/kg)-induced motor activity. Pretreatment with H7 (30.0 nmol/side) also blocked the cocaine-induced rise of extracellular dopamine in a terminal region of the mesolimbic dopamine system, the nucleus accumbens, as measured by in vivo microdialysis. These data suggest that activation of protein kinases may be important in cocaine-induced motor activity.
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Affiliation(s)
- J D Steketee
- Department of Pharmacology and Therapeutics, Louisiana State University Medical Center, Shreveport 71130-3932
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40
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Vezina P. Amphetamine injected into the ventral tegmental area sensitizes the nucleus accumbens dopaminergic response to systemic amphetamine: an in vivo microdialysis study in the rat. Brain Res 1993; 605:332-7. [PMID: 8386970 DOI: 10.1016/0006-8993(93)91761-g] [Citation(s) in RCA: 123] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Different groups of rats received three injections of either D-amphetamine (2.5 micrograms/0.5 microliters/side) or saline into the ventral tegmental area (VTA), one injection every third day. Two weeks following the last injection, dopamine (DA) neurotransmission in the nucleus accumbens (N. Acc.) was assessed with in vivo microdialysis before and after a challenge with systemic D-amphetamine (1.0 mg/kg, i.p.). Prior to challenge, basal extracellular concentrations of DA in the N.Acc. did not differ in VTA amphetamine- and saline-preexposed animals. Following challenge, however, both groups showed an increase in N.Acc. DA but this was significantly greater (2-fold) in VTA amphetamine-preexposed animals. These latter animals also showed significantly higher DA metabolite levels in comparison to saline-preexposed animals prior to (DOPAC) as well as after challenge (HVA). These findings extend those of behavioral experiments showing that intra-VTA amphetamine produces sensitized locomotor responding to drug challenge (J. Pharmacol. Exp. Ther., 245 (1988) 1095-1102; Brain Res., 516 (1990) 99-106; Ann. NY Acad. Sci., 654 (1992) 444-447) and demonstrate that amphetamine applied to the somatodendritic region of mesolimbic DA neurons sensitizes these neurons as evidenced by their enhanced N.Acc. DA response to a systemic amphetamine challenge.
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Affiliation(s)
- P Vezina
- Neurosciences, Loeb Medical Research Institute, Ottawa Civic Hospital, Ont., Canada
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41
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Hooks MS, Jones GH, Liem BJ, Justice JB. Sensitization and individual differences to IP amphetamine, cocaine, or caffeine following repeated intracranial amphetamine infusions. Pharmacol Biochem Behav 1992; 43:815-23. [PMID: 1448477 DOI: 10.1016/0091-3057(92)90413-a] [Citation(s) in RCA: 72] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Rats that have a high locomotor response to novelty (HR) sensitize more readily to IP-administered amphetamine than rats with a low locomotor response (LR) to novelty. This experiment compared sensitization in HR and LR rats following amphetamine (3.0 micrograms/side for 5 days) infused bilaterally into either the nucleus accumbens (NACC), ventral tegmental area (VTA), or the medial frontal cortex (MFC). The subsequent locomotor response to IP-administered d-amphetamine sulfate (1 mg/kg), cocaine HCl (15 mg/kg), and caffeine benzoate (20 mg/kg) was also examined. No differences were observed between HR and LR rats following amphetamine infusion into either the MFC, NACC, or VTA. However, HR rats showed greater locomotor activity compared to LR rats following either IP amphetamine, cocaine, or caffeine for subjects cannulated in the NACC, MFC, or the VTA. Repeated infusions of amphetamine into the VTA increased the locomotor response to both IP amphetamine and cocaine, but not to IP caffeine, while repeated infusions of amphetamine into the NACC or MFC had no effect on locomotor response to any drug subsequently administered IP. The results support previous findings that changes induced by intra-VTA infusions, but not intra-NACC or MFC infusions, of amphetamine induce sensitization to IP-administered amphetamine and cocaine. Findings from the present experiment indicate the ability of the dopamine cell body region, but not the dopamine terminal fields, to produce locomotor sensitization to amphetamine and cocaine. The results from the present experiment also indicate the lack of localization to one of studied regions of individual differences.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- M S Hooks
- Department of Chemistry, Emory University, Atlanta, GA 30322
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42
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Affiliation(s)
- J Stewart
- Department of Psychology, Concordia University, Montréal, Québec, Canada
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43
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Henry DJ, White FJ. Electrophysiological correlates of psychomotor stimulant-induced sensitization. Ann N Y Acad Sci 1992; 654:88-100. [PMID: 1385937 DOI: 10.1111/j.1749-6632.1992.tb25958.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Affiliation(s)
- D J Henry
- Department of Psychiatry, Wayne State University School of Medicine, Detroit, Michigan 48207
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44
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Kalivas PW, Striplin CD, Steketee JD, Klitenick MA, Duffy P. Cellular mechanisms of behavioral sensitization to drugs of abuse. Ann N Y Acad Sci 1992; 654:128-35. [PMID: 1632577 DOI: 10.1111/j.1749-6632.1992.tb25961.x] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Affiliation(s)
- P W Kalivas
- Alcoholism and Drug Abuse Program, Washington State University, Pullman 99164-6530
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45
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Striplin CD, Kalivas PW. Correlation between behavioral sensitization to cocaine and G protein ADP-ribosylation in the ventral tegmental area. Brain Res 1992; 579:181-6. [PMID: 1628210 DOI: 10.1016/0006-8993(92)90049-f] [Citation(s) in RCA: 55] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The ventral tegmental area is a site of action by psychostimulants in the production of behavioral sensitization. Recently, G proteins of the ventral tegmental area have been implicated in behavioral sensitization to cocaine. To further investigate the specific role of G proteins, rats were treated with either 15 or 30 mg/kg, i.p., of cocaine (x 5 days), and at 1, 6 or 24 h after the last injection in vitro pertussis toxin catalyzed adenosine diphosphate (ADP)-ribosylation was used to measure the G proteins in the ventral tegmental area, nucleus accumbens, prefrontal cortex, substantia nigra, and striatum. A significant decline in the ADP-ribosylation of G proteins, specific for the ventral tegmental area, was observed at 1 and/or 6 h but had returned to normal by 24 h. A significant negative correlation was found between the percent of G proteins ADP-ribosylated in the ventral tegmental area and the behavioral activity elicited in sensitized but not acute cocaine-treated animals at 1 h after injection. These data suggest that the G proteins ADP-ribosylated by pertussis toxin may be involved in the sensitized motor response produced by repeated cocaine administration in rats.
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Affiliation(s)
- C D Striplin
- Department of Veterinary Comparative Anatomy, Pharmacology and Physiology, Washington State University, Pullman 99164-6520
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46
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Kalivas PW, Stewart J. Dopamine transmission in the initiation and expression of drug- and stress-induced sensitization of motor activity. BRAIN RESEARCH. BRAIN RESEARCH REVIEWS 1991; 16:223-44. [PMID: 1665095 DOI: 10.1016/0165-0173(91)90007-u] [Citation(s) in RCA: 1426] [Impact Index Per Article: 43.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Progress has been made over the last 10 years in determining the neural mechanisms of sensitization induced by amphetamine-like psychostimulants, opioids and stressors. Changes in dopamine transmission in axon terminal fields such as the nucleus accumbens appear to underlie the expression of sensitization, but the actions of drugs and stressors in the somatodendritic regions of the A10/A9 dopamine neurons seem critical for the initiation of sensitization. Manipulations that increase somatodendritic dopamine release and permit the stimulation of D1 dopamine receptors in this region induce changes in the dopamine system that lead to the development of long-term sensitization. However, it is not known exactly how the changes in the A10/A9 region are encoded to permit augmented dopamine transmission in the terminal field. One possibility is that the dopamine neurons of sensitized animals have become increasingly sensitive to excitatory pharmacological and environmental stimuli or desensitized to inhibitory regulation. Alternatively, changes in cellular activity or protein synthesis may result in a change in the presynaptic regulation of axon terminal dopamine release.
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Affiliation(s)
- P W Kalivas
- Alcohol and Drug Abuse Program, Washington State University, Pullman 99164-6530
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47
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Steketee JD, Striplin CD, Murray TF, Kalivas PW. Possible role for G-proteins in behavioral sensitization to cocaine. Brain Res 1991; 545:287-91. [PMID: 1907213 DOI: 10.1016/0006-8993(91)91299-g] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The role of G-proteins in behavioral sensitization to cocaine was examined by injecting pertussis toxin (PTX) into the A10 dopamine cell group. The capacity of acute cocaine to increase motor activity and dopamine release in the nucleus accumbens was significantly augmented in rats pretreated 14 days earlier with PTX. These data suggest that injection of PTX into the A10 dopamine cell group produces a long-term alteration in mesolimbic dopamine function, and implicates A10 dopamine neurons and G-proteins in the development of behavioral sensitization.
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Affiliation(s)
- J D Steketee
- Department of Veterinary and Comparative Anatomy, Washington State University, Pullman 99164-6520
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48
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Yoshikawa T, Shibuya H, Kaneno S, Toru M. Blockade of behavioral sensitization to methamphetamine by lesion of hippocampo-accumbal pathway. Life Sci 1991; 48:1325-32. [PMID: 2002758 DOI: 10.1016/0024-3205(91)90529-k] [Citation(s) in RCA: 30] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The present studies were carried out to explore a role of the hippocampal efferents in the development of the locomotor augmentation induced by repeated methamphetamine administrations. For this purpose, electrolytic lesions of either the dorsal fornix or the fimbria fornix were made bilaterally in rats. The latter treatment, not the former, blocked the behavioral sensitization. These results suggest that the hippocampo-accumbal pathway may play an important role in the development of the sensitization.
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Affiliation(s)
- T Yoshikawa
- Department of Neuropsychiatry, Faculty of Medicine, Tokyo Medical and Dental University, Japan
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49
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Deutch AY, Roth RH. The determinants of stress-induced activation of the prefrontal cortical dopamine system. PROGRESS IN BRAIN RESEARCH 1991; 85:367-402; discussion 402-3. [PMID: 2094906 DOI: 10.1016/s0079-6123(08)62691-6] [Citation(s) in RCA: 230] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Affiliation(s)
- A Y Deutch
- Department of Psychiatry, Yale University School of Medicine, New Haven, CT 06508
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Paulson PE, Robinson TE. Sensitization to systemic amphetamine produces an enhanced locomotor response to a subsequent intra-accumbens amphetamine challenge in rats. Psychopharmacology (Berl) 1991; 104:140-1. [PMID: 1882000 PMCID: PMC1859850 DOI: 10.1007/bf02244569] [Citation(s) in RCA: 60] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Repeated amphetamine (AMPH) administration into the nucleus accumbens does not enhance (sensitize) the locomotor activity produced by a subsequent systemic AMPH challenge. We report here, however, that pretreatment with systemic injections of AMPH does produce a significant enhancement in the locomotor stimulant effects produced by intra-accumbens AMPH given 21 days after the last pretreatment injection of AMPH. These data support the hypothesis that neural adaptations in dopamine (DA) terminal fields are sufficient for the expression of AMPH sensitization, although an action on DA cell bodies may be required for the induction of AMPH sensitization.
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Affiliation(s)
- P E Paulson
- Department of Psychology, University of Michigan, Ann Arbor 48109
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