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Depression-Associated Negr1 Gene-Deficiency Induces Alterations in the Monoaminergic Neurotransmission Enhancing Time-Dependent Sensitization to Amphetamine in Male Mice. Brain Sci 2022; 12:brainsci12121696. [PMID: 36552158 PMCID: PMC9776224 DOI: 10.3390/brainsci12121696] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2022] [Revised: 12/07/2022] [Accepted: 12/08/2022] [Indexed: 12/14/2022] Open
Abstract
In GWAS studies, the neural adhesion molecule encoding the neuronal growth regulator 1 (NEGR1) gene has been consistently linked with both depression and obesity. Although the linkage between NEGR1 and depression is the strongest, evidence also suggests the involvement of NEGR1 in a wide spectrum of psychiatric conditions. Here we show the expression of NEGR1 both in tyrosine- and tryptophan hydroxylase-positive cells. Negr1-/- mice show a time-dependent increase in behavioral sensitization to amphetamine associated with increased dopamine release in both the dorsal and ventral striatum. Upregulation of transcripts encoding dopamine and serotonin transporters and higher levels of several monoamines and their metabolites was evident in distinct brain areas of Negr1-/- mice. Chronic (23 days) escitalopram-induced reduction of serotonin and dopamine turnover is enhanced in Negr1-/- mice, and escitalopram rescued reduced weight of hippocampi in Negr1-/- mice. The current study is the first to show alterations in the brain monoaminergic systems in Negr1-deficient mice, suggesting that monoaminergic neural circuits contribute to both depressive and obesity-related phenotypes linked to the human NEGR1 gene.
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Tapia MA, Lever JR, Lever SZ, Will MJ, Park ES, Miller DK. Sigma-1 receptor ligand PD144418 and sigma-2 receptor ligand YUN-252 attenuate the stimulant effects of methamphetamine in mice. Psychopharmacology (Berl) 2019; 236:3147-3158. [PMID: 31139878 DOI: 10.1007/s00213-019-05268-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/10/2019] [Accepted: 05/01/2019] [Indexed: 12/12/2022]
Abstract
RATIONALE Previous research indicates that the selective sigma-1 receptor ligand PD144418 and the selective sigma-2 ligands YUN-252 can inhibit cocaine-induced hyperactivity. The effects of these ligands on other stimulants, such as methamphetamine, have not been reported. OBJECTIVES The present study examined the effects of PD144418 and YUN-252 pretreatment on methamphetamine-induced hyperactivity after acute treatment. METHODS Mice (n = 8-14/group) were injected with PD144418 (3.16, 10, or 31.6 μmol/kg), YUN-252 (0.316, 3.16, 31.6 μmol/kg), or saline. After 15 min, mice injected with 2.69 μmol/kg methamphetamine or saline vehicle, where distance traveled during a 60-min period was recorded. Additionally, the effect of PD144418 on the initiation and expression of methamphetamine sensitization was determined by treating mice (n = 8-14/group) with PD144418, methamphetamine or saline repeatedly over a 5-day period, and testing said mice with a challenge dose after a 7-day withdrawal period. RESULTS Results indicate that both PD144418 and YUN-252, in a dose-dependent manner, attenuated hyperactivity induced by an acute methamphetamine injection. Specifically, 10 μmol/kg or 31.6 μmol/kg of PD144418 and 31 μmol/kg of YUN-252 suppressed methamphetamine-induced hyperactivity. In regard to methamphetamine sensitization, while 10 μmol/kg PD144418 prevented the initiation of methamphetamine sensitization, it did not have an effect on the expression. CONCLUSIONS Overall, the current results suggest an intriguing potential for this novel sigma receptor ligand as a treatment for the addictive properties of methamphetamine. Future analysis of this novel sigma receptor ligand in assays directly measuring reinforcement properties will be critical.
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Affiliation(s)
- Melissa A Tapia
- Department of Psychological Sciences, University of Missouri, 210 McAlester Hall, Columbia, MO, 65211, USA.
| | - John R Lever
- Research Service, Harry S. Truman Memorial Veterans' Hospital, Columbia, and Department of Radiology and Radiopharmaceutical Sciences Institute, University of Missouri, Columbia, MO, 65211, USA
| | - Susan Z Lever
- Department of Chemistry and MU Research Reactor Center, University of Missouri, Columbia, MO, 65211, USA
| | - Matthew J Will
- Department of Psychological Sciences, University of Missouri, 210 McAlester Hall, Columbia, MO, 65211, USA
| | - Eric S Park
- Department of Psychological Sciences, University of Missouri, 210 McAlester Hall, Columbia, MO, 65211, USA
| | - Dennis K Miller
- Department of Psychological Sciences, University of Missouri, 210 McAlester Hall, Columbia, MO, 65211, USA
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Sulzer D, Cragg SJ, Rice ME. Striatal dopamine neurotransmission: regulation of release and uptake. ACTA ACUST UNITED AC 2016; 6:123-148. [PMID: 27141430 DOI: 10.1016/j.baga.2016.02.001] [Citation(s) in RCA: 236] [Impact Index Per Article: 29.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Dopamine (DA) transmission is governed by processes that regulate release from axonal boutons in the forebrain and the somatodendritic compartment in midbrain, and by clearance by the DA transporter, diffusion, and extracellular metabolism. We review how axonal DA release is regulated by neuronal activity and by autoreceptors and heteroreceptors, and address how quantal release events are regulated in size and frequency. In brain regions densely innervated by DA axons, DA clearance is due predominantly to uptake by the DA transporter, whereas in cortex, midbrain, and other regions with relatively sparse DA inputs, the norepinephrine transporter and diffusion are involved. We discuss the role of DA uptake in restricting the sphere of influence of DA and in temporal accumulation of extracellular DA levels upon successive action potentials. The tonic discharge activity of DA neurons may be translated into a tonic extracellular DA level, whereas their bursting activity can generate discrete extracellular DA transients.
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Affiliation(s)
- David Sulzer
- Depts of Psychiatry, Neurology, & Pharmacology, NY State Psychiatric Institute, Columbia University, New York, NY, USA
| | - Stephanie J Cragg
- Dept Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK
| | - Margaret E Rice
- Depts of Neurosurgery & Neuroscience and Physiology, New York University School of Medicine, New York, NY, USA
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Vanhanen J, Kinnunen M, Nuutinen S, Panula P. Histamine H3 receptor antagonist JNJ-39220675 modulates locomotor responses but not place conditioning by dopaminergic drugs. Psychopharmacology (Berl) 2015; 232:1143-53. [PMID: 25308376 DOI: 10.1007/s00213-014-3751-7] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/04/2014] [Accepted: 09/15/2014] [Indexed: 12/31/2022]
Abstract
RATIONALE Brain histaminergic system is involved in the regulation of the dopaminergic circuitry. The role of histamine H3 receptor (H3R) in behaviors linked to amphetamine addiction and other behaviors induced by dopaminergic compounds has remained unclear. OBJECTIVE Our aim was to study whether H3R antagonist JNJ-39220675 inhibits amphetamine-induced stimulation and reward. The effects of JNJ-39220675 on dopamine D2-like receptor (D2R-like) agonist quinpirole-induced behaviors were also investigated in order to clarify whether the possible effects of H3R antagonists are D2R-like dependent. METHODS The effects of JNJ-39220675 on amphetamine and quinpirole-induced behavioral responses in mice were studied assessing the locomotor activation after both acute and repeated administrations of amphetamine and quinpirole. The place conditioning paradigm was also used as a measure of reward or aversion. RESULTS JNJ-39220675 inhibited amphetamine-induced stimulation acutely but not after repeated administrations. Amphetamine (2 mg/kg) induced conditioned place preference that was not affected by either of the tested doses of JNJ-39220675 (1 and 10 mg/kg). Quinpirole (0.5 mg/kg) induced conditioned place aversion to which the pretreatment by JNJ-39220675 (10 mg/kg) had no effect. In repeated administration, JNJ-39220675 did, however, inhibit quinpirole-induced tolerance to hypokinesia. CONCLUSIONS Our results show that although H3R antagonists inhibit ethanol reward, they may not possess the same ability on psychostimulants, such as amphetamine. However, if H3R antagonists will become clinically available, it is of importance that these compounds potentiate neither the rewarding nor aversive effects of other drugs.
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Affiliation(s)
- Jenni Vanhanen
- Neuroscience Center and Institute of Biomedicine/Anatomy, University of Helsinki, P.O. Box 63 (Haartmaninkatu 8), 00014, Helsinki, Finland
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Striatal dopamine receptor plasticity in neurotensin deficient mice. Behav Brain Res 2014; 280:160-71. [PMID: 25449842 DOI: 10.1016/j.bbr.2014.11.014] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2014] [Revised: 11/04/2014] [Accepted: 11/07/2014] [Indexed: 11/21/2022]
Abstract
Schizophrenia is thought to be caused, at least in part, by dysfunction in striatal dopamine neurotransmission. Both clinical studies and animal research have implicated the dopamine neuromodulator neurotensin (NT) in the pathophysiology of schizophrenia. Utilizing male mice lacking the NT gene (NT(-/-)), these studies examined the consequences of NT deficiency on dopaminergic tone and function, investigating (1) dopamine concentrations and dopamine receptor and transporter expression and binding in dopaminergic terminal regions, and (2) the behavioral effects of selective dopamine receptor agonists on locomotion and sensorimotor gating in adult NT(-/-) mice compared to wildtype (NT(+/+)) mice. NT(-/-) mice did not differ from NT(+/+) mice in concentrations of dopamine or its metabolite DOPAC in any brain region examined. However, NT(-/-) mice showed significantly increased D1 receptor, D2 receptor, and dopamine transporter (DAT) mRNA in the caudate putamen compared to NT(+/+) controls. NT(-/-) mice also showed elevated D2 receptor binding densities in both the caudate putamen and nucleus accumbens shell compared to NT(+/+) mice. In addition, some of the behavioral effects of the D1-type receptor agonist SKF-82958 and the D2-type receptor agonist quinpirole on locomotion, startle amplitude, and prepulse inhibition were dose-dependently altered in NT(-/-) mice, showing altered D1-type and D2-type receptor sensitivity to stimulation by agonists in the absence of NT. The results indicate that NT deficiency alters striatal dopamine receptor expression, binding, and function. This suggests a critical role for the NT system in the maintenance of striatal DA system homeostasis and implicates NT deficiency in the etiology of dopamine-associated disorders such as schizophrenia.
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Hadad NA, Knackstedt LA. Addicted to palatable foods: comparing the neurobiology of Bulimia Nervosa to that of drug addiction. Psychopharmacology (Berl) 2014; 231:1897-912. [PMID: 24500676 PMCID: PMC4484591 DOI: 10.1007/s00213-014-3461-1] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/14/2013] [Accepted: 01/20/2014] [Indexed: 12/18/2022]
Abstract
RATIONALE Bulimia nervosa (BN) is highly comorbid with substance abuse and shares common phenotypic and genetic predispositions with drug addiction. Although treatments for the two disorders are similar, controversy remains about whether BN should be classified as addiction. OBJECTIVES Here, we review the animal and human literature with the goal of assessing whether BN and drug addiction share a common neurobiology. RESULTS Similar neurobiological features are present following administration of drugs and bingeing on palatable food, especially sugar. Specifically, both disorders involve increases in extracellular dopamine (DA), D1 binding, D3 messenger RNA (mRNA), and ΔFosB in the nucleus accumbens (NAc). Animal models of BN reveal increases in ventral tegmental area (VTA) DA and enzymes involved in DA synthesis that resemble changes observed after exposure to addictive drugs. Additionally, alterations in the expression of glutamate receptors and prefrontal cortex activity present in human BN or following sugar bingeing in animals are comparable to the effects of addictive drugs. The two disorders differ in regards to alterations in NAc D2 binding, VTA DAT mRNA expression, and the efficacy of drugs targeting glutamate to treat these disorders. CONCLUSIONS Although additional empirical studies are necessary, the synthesis of the two bodies of research presented here suggests that BN shares many neurobiological features with drug addiction. While few Food and Drug Administration-approved options currently exist for the treatment of drug addiction, pharmacotherapies developed in the future, which target the glutamate, DA, and opioid systems, may be beneficial for the treatment of both BN and drug addiction.
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Affiliation(s)
- Natalie A Hadad
- Department of Psychology, University of Florida, P.O. Box 112250, Gainesville, FL, 32611-2250, USA
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Singer BF, Scott-Railton J, Vezina P. Unpredictable saccharin reinforcement enhances locomotor responding to amphetamine. Behav Brain Res 2011; 226:340-4. [PMID: 21924296 DOI: 10.1016/j.bbr.2011.09.003] [Citation(s) in RCA: 94] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2011] [Revised: 08/31/2011] [Accepted: 09/02/2011] [Indexed: 11/16/2022]
Abstract
Drug-naïve, non-deprived rats were trained to lever press for saccharin under fixed-ratio (FR) or variable-ratio (VR) schedules of reinforcement. Rats trained on the VR schedule in which saccharin reinforcement was not predicted by a fixed number of lever presses subsequently showed an enhanced locomotor response to a threshold amphetamine challenge injection (0.5mg/kg IP) administered 2 weeks following the last saccharin session. This finding suggests that chronic exposure to gambling-like conditions of uncertain reinforcement can induce neuroadaptations in brain reward systems that are similar to those produced by repeated psychostimulant exposure and may lead to the development of addictive behaviors.
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Affiliation(s)
- B F Singer
- Committee on Neurobiology, The University of Chicago, Chicago, IL 60637, USA.
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Hewitt KN, Marsden CA, Hollis CP, Fone KCF. Behavioural characterisation of the effects of acute and repeated administration of GBR 12909 in rats: further evaluation of a potential model of ADHD. Neuropharmacology 2009; 57:678-86. [PMID: 19699754 DOI: 10.1016/j.neuropharm.2009.08.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2009] [Revised: 08/13/2009] [Accepted: 08/14/2009] [Indexed: 11/15/2022]
Abstract
Attention deficit hyperactivity disorder (ADHD) is a common neuropsychiatric disorder characterised by excessive levels of hyperactivity, inattentiveness and impulsivity. Stimulant drugs which increase dopamine neurotransmission are treatments for ADHD. Hypodopaminergic fronto-striatal function with associated overactivity of the dopamine transporter (DAT) represents one possible neurobiological mechanism underlying ADHD. Few, if any, of the existing animal models of ADHD mimic the underlying neurobiology of the disorder. In this study we have further characterised the behavioural profile of a model of a hyperactive inattentive animal through manipulation of the DAT. The behavioural effects of acute treatment and following withdrawal from sub-chronic treatment with GBR 12909 (30 mg/kg i.p.), a potent and highly selective DAT inhibitor, were examined in juvenile rats. GBR 12909 treatment was used to produce a compensatory up regulation following withdrawal. Acute treatment with GBR 12909 (30 mg/kg i.p.) resulted in a marked increase in locomotor and rearing behaviours on the first and fourth days during a 4 consecutive bi-daily drug treatment regime in postnatal weaned rats. Adolescent rats after 10, 20 and 30 days withdrawal from GBR 12909 pre-treatment maintained mild increases in locomotor activity and failed to discriminate a familiar over a novel object in the novel object discrimination task (using both 1 min and 3 h inter-trial intervals) indicating impaired learning and memory. Prepulse inhibition of acoustic startle was unaltered following withdrawal from GBR 12909 treatment. These data reinforce the potential role of the DAT in the underlying neurobiology of ADHD. They also add further evidence to suggest that postnatal changes in the DAT following withdrawal from treatment with the DAT inhibitor, GBR 12909, may prove to be a useful animal model of ADHD with potential for examining the effectiveness of novel ADHD treatments.
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Affiliation(s)
- Katherine N Hewitt
- Institute of Neuroscience, School of Biomedical Sciences, Medical School, Queens Medical Centre, University of Nottingham, Nottingham NG7 2UH, UK.
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de Jong I, Steenbergen P, de Kloet E. Strain differences in the effects of adrenalectomy on the midbrain dopamine system: Implication for behavioral sensitization to cocaine. Neuroscience 2008; 153:594-604. [DOI: 10.1016/j.neuroscience.2008.03.004] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2007] [Revised: 03/01/2008] [Accepted: 03/03/2008] [Indexed: 11/25/2022]
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Perreault ML, Graham D, Scattolon S, Wang Y, Szechtman H, Foster JA. Cotreatment with the kappa opioid agonist U69593 enhances locomotor sensitization to the D2/D3 dopamine agonist quinpirole and alters dopamine D2 receptor and prodynorphin mRNA expression in rats. Psychopharmacology (Berl) 2007; 194:485-96. [PMID: 17619861 DOI: 10.1007/s00213-007-0855-3] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/09/2007] [Accepted: 06/08/2007] [Indexed: 11/30/2022]
Abstract
RATIONALE The repeated coadministration of the kappa opioid receptor agonist U69593 with the D2/D3 dopamine (DA) agonist quinpirole (QNP) potentiates locomotor sensitization induced by QNP. Behavioral evidence has implicated both pre- and postsynaptic changes as being involved in this augmentation. OBJECTIVES The objectives of this study were to obtain supporting molecular evidence of pre- and/or postsynaptic alterations in the DA system with U69593/QNP cotreatment and to examine the relationship of such changes to locomotor sensitization. MATERIALS AND METHODS Gene expression of D1 and D2 receptors (D1R and D2R), the DA transporter, as well as the endogenous opioid prodynorphin (DYN), in the basal ganglia was examined by in situ hybridization in rats after one or ten drug injections. RESULTS After one injection, changes that were specific to U69593/QNP cotreatment were decreased D1R and D2R messenger RNA (mRNA) in the nucleus accumbens (Acb) shell and increased DYN mRNA in the dorsal striatum (STR). After ten injections, U69593/QNP-specific changes were decreased D2R mRNA in substantia nigra (SN) and increased DYN mRNA in STR and Acb core. Only in U69593/QNP rats was the sensitized locomotor performance on injection ten positively correlated with DYN mRNA levels in Acb and STR. CONCLUSIONS Distinct alterations of D2R and DYN mRNA levels in SN and Acb/STR, respectively, strengthen the evidence implicating pre- and postsynaptic changes in augmented locomotor sensitization to U69593/QNP cotreatment. It is suggested that repeated U69593/QNP cotreatment may augment locomotor sensitization to QNP by activating D1R-expressing DYN neurons and attenuating presynaptic D2R function.
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Affiliation(s)
- Melissa L Perreault
- Department of Psychiatry and Behavioural Neurosciences, Health Science Centre, Room 4N7, McMaster University, Hamilton, ON, Canada.
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Belin D, Deroche-Gamonet V, Jaber M. Cocaine-induced sensitization is associated with altered dynamics of transcriptional responses of the dopamine transporter, tyrosine hydroxylase, and dopamine D2 receptors in C57Bl/6J mice. Psychopharmacology (Berl) 2007; 193:567-78. [PMID: 17505818 DOI: 10.1007/s00213-007-0790-3] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/18/2006] [Accepted: 04/03/2007] [Indexed: 11/25/2022]
Abstract
RATIONALE Behavioural sensitization is a long lasting phenomenon that has been proposed to be involved in drug addiction. Although the expression of cocaine-induced sensitization has been associated with the activity of the mesencephalic dopaminergic neurons, little is known about the transcriptional adaptations of these neurons to a new challenge with cocaine long after cessation of repeated exposure to the drug. OBJECTIVES We studied the time course of the mRNA levels of three main regulatory elements of dopaminergic transmission after a challenge with cocaine (15 mg/kg) that followed 21 days of withdrawal from a cocaine pretreatment (20 mg/kg, ip, every 2 days for 21 days) in C57Bl/6J mice. MATERIALS AND METHODS Mice were placed 45 min in activity chambers and were killed 45 min, 2 h or 24 h after the challenge injection. Dopamine transporter (DAT), D2 auto-receptor (D2) and tyrosine hydroxylase (TH) mRNA levels were assessed by in situ hybridization in the ventral tegmental area and the substantia nigra compacta. RESULTS As compared to vehicle challenge, cocaine challenge in vehicle pretreated mice induced a rapid increase (+208%) in DAT mRNA (45 min) followed by a delayed decrease (-70%) (24 h), while TH and D2 mRNA were both increased (+45%) 24 h after the challenge. In cocaine pretreated mice, cocaine-induced short-term increase and long-term decrease in DAT mRNA levels were amplified (+328%) and reduced (-40%), respectively. CONCLUSIONS Repeated exposure to cocaine alters the transcriptional response of DA neurons to a new cocaine challenge long after cessation of repeated exposure to the drug. They point to the DAT mRNA as a major responsive element to a new presentation of cocaine.
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Affiliation(s)
- D Belin
- CRI U862, INSERM, 146 rue Léo Saignat, 33077 Bordeaux Cedex, France
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Kitanaka J, Kitanaka N, Takemura M. Neurochemical consequences of dysphoric state during amphetamine withdrawal in animal models: a review. Neurochem Res 2007; 33:204-19. [PMID: 17605106 DOI: 10.1007/s11064-007-9409-7] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2007] [Accepted: 06/07/2007] [Indexed: 10/23/2022]
Abstract
Chronic abuse of amphetamines, such as d-amphetamine (AMPH) and d-methamphetamine, results in psychological dependence, a condition in which the drug produces a feeling of satisfaction and a drive that requires periodic or continuous administration of the drug to produce overwhelming pleasure or to avoid discomfort such as dysphoria. The dysphoric state of AMPH withdrawal has been recognized as depressive syndromes, such as anhedonia, depression, anxiety, and social inhibition, in early drug abstinence. Medication for treatment of the dysphoric state is important for AMPH abusers to avoid impulsive self-injurious behavior or acts that are committed with unconscious or uncontrolled suicidal ideation. However, successful treatments for AMPH withdrawal remain elusive, since the exact molecular basis of the expression of dysphoria has not been fully elucidated. This review focuses on the molecular aspects of AMPH withdrawal as indexed by neurochemical parameters under a variety of injection regimens (for example, levels of brain monoamines and their metabolites, and gamma-aminobutyric acid, expression of genes and proteins involved in neuronal activity, and monoamine metabolism and availability) in rodent models which exhibit significant phenotypic features relevant to the syndromes of AMPH withdrawal in humans.
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Affiliation(s)
- Junichi Kitanaka
- Department of Pharmacology, Hyogo College of Medicine, 1-1 Mukogawa-cho, Nishinomiya, Hyogo 663-8501, Japan.
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Broom SL, Yamamoto BK. Effects of subchronic methamphetamine exposure on basal dopamine and stress-induced dopamine release in the nucleus accumbens shell of rats. Psychopharmacology (Berl) 2005; 181:467-76. [PMID: 15986185 DOI: 10.1007/s00213-005-0007-6] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/24/2004] [Accepted: 03/15/2005] [Indexed: 10/25/2022]
Abstract
RATIONALE Subchronic administration of stimulants reduces basal dopamine (DA) concentrations and blocks stress-induced DA release in the nucleus accumbens (NA) of rats during withdrawal. However, no studies have attempted to relate early withdrawal from chronic drug exposure to stress reactivity and changes in DA transmission. OBJECTIVES The effects of subchronic low-dose methamphetamine (METH) administration on regional changes in dopamine transporter (DAT) and norepinephrine transporter (NET) immunoreactivity and function during early withdrawal were examined. The effects of subchronic METH on stress responsivity measured by DA release in the nucleus accumbens shell (NA SHELL) and core (NA CORE) during acute restraint stress were also examined. METHODS Male rats received single injections of METH (2.0 mg/kg i.p.) or saline (SAL) for 10 days and then were killed 24 h after the last injection. DAT and NET protein in NA, striatum (STR), medial prefrontal cortex (mPFC), and hippocampus were assayed by Western blot analysis. Experiment 2 measured basal extracellular DA concentrations and restraint-stress-induced DA release in vivo in the NA SHELL and CORE of SAL- and METH-pretreated rats after 24-h withdrawal. Experiment 3 examined the in vivo regulation of extracellular DA in the NA SHELL and/or CORE after local administration of GBR12909 (50 microM) or nisoxetine (100 microM; NA SHELL). RESULTS Subchronic METH increased DAT but not NET immunoreactivity in the NA compared to the STR and mPFC. METH reduced basal extracellular DA and blocked restraint-stress-induced DA release in the NA SHELL. DA uptake blockade increased extracellular DA more in the NA SHELL of METH rats, whereas NE uptake blockade increased basal DA concentrations to a similar extent in METH and SAL rats. CONCLUSIONS These results suggest that subchronic METH exposure selectively increases NA DAT and consequently reduces basal and stress-induced DA release in the NA SHELL during early withdrawal.
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Affiliation(s)
- Susan L Broom
- Department of Pharmacology and Experimental Therapeutics, Boston University School of Medicine, Room L-613, 715 Albany Street, Boston, MA 02118, USA
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14
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Fang YR, Abekawa T, Li XB, Wang ZC, Inoue T, Koyama T. Effect of the protein kinase C inhibitor, staurosporine, on the high dose of methamphetamine-induced behavioral sensitization to dizocilpine (MK-801). Psychopharmacology (Berl) 2005; 180:100-6. [PMID: 15682296 DOI: 10.1007/s00213-005-2145-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/21/2004] [Accepted: 11/23/2004] [Indexed: 10/25/2022]
Abstract
RATIONALE In our preliminary study, methamphetamine (METH) at 2.5 mg/kg, but not at 1.0 mg/kg, induced a delayed increase in glutamate levels in the nucleus accumbens (NAc). We hypothesize that repeated increases in glutamate levels produces behavioral sensitization to a selective uncompetitive N-methyl-D-aspartate (NMDA) receptor antagonist, dizocilpine (MK-801), and that an activation of protein kinase C (PKC) plays an important role for this sensitization. OBJECTIVES This study was conducted to confirm delayed increases in glutamate levels induced by a higher dose of METH (2.5 mg/kg), and to examine the effect of straurosporine, a PKC inhibitor, on the higher dose of METH-induced sensitization to dizocilpine. METHODS The effects of METH on extracellular glutamate levels in the NAc were studied using in vivo microdialysis. Locomotor activity was measured by using an infrared sensor. RESULTS METH at 2.5 mg/kg, but not at 1.0 mg/kg, induced delayed increases in glutamate levels. The acute administration of staurosporine did not affect the locomotor activity by a single injection of METH (2.5 mg/kg). Repeated METH administrations (2.5 mg/kg, once in every other day, for five times) developed behavioral sensitization to the locomotion-inducing effect of dizocilpine (0.2 mg/kg), a selective uncompetitive NMDA receptor antagonist. Staurosporine (0.1 mg/kg), given 120 min later for every METH treatment, inhibited the development of behavioral sensitization to dizocilpine. CONCLUSIONS These results suggest the involvement of increased glutamate levels and an activation of PKC in delayed-induced synaptic and cellular plasticity underlying the higher dose of METH-induced behavioral sensitization to dizocilpine.
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Affiliation(s)
- Y R Fang
- Department of Psychiatry of Shanghai Second Medical University, Shanghai Mental Health Center, 600 Wan Ping Nan Road, Shanghai, 200030, China.
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Copeland BJ, Neff NH, Hadjiconstantinou M. Enhanced dopamine uptake in the striatum following repeatedrestraint stress. Synapse 2005; 57:167-74. [PMID: 15945060 DOI: 10.1002/syn.20169] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
In mice administered chronic stress--repeated overnight restraint stress for 7 days--there was a prolonged enhancement of dopamine (DA) uptake into synaptosomes. The mRNA for the DA transporter (DAT) was found to be concomitantly increased in the midbrain, as was the binding of the transporter ligand mazindol to DAT in the nucleus accumbens and caudate-putamen. Kinetic analysis showed an increase in Vmax for DA, with little change in Km. No changes in tyrosine hydroxylase activity and tissue DA or 3,4-dihydroxyphenylacetic acid (DOPAC) content were observed. However, homovanillic acid (HVA) was found to be increased in the striatum of the stressed animals. Enhanced DAT activity attributable to chronic stress was still observed in animals treated with the DA D2 receptor antagonist haloperidol or the glucocorticoid receptor antagonist mifepristone. Modulation of DAT activity may be a physiological mechanism for regulating the concentration of DA that reaches receptors, following periods of stress.
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Affiliation(s)
- Benjamin J Copeland
- The Neuroscience Program, Division of Molecular Neuropsychopharmacology, The Ohio State University College of Medicine and Public Health, Columbus, Ohio 43210, USA
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16
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Armstrong V, Reichel CM, Doti JF, Crawford CA, McDougall SA. Repeated amphetamine treatment causes a persistent elevation of glial fibrillary acidic protein in the caudate-putamen. Eur J Pharmacol 2004; 488:111-5. [PMID: 15044042 DOI: 10.1016/j.ejphar.2004.02.001] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2003] [Revised: 01/26/2004] [Accepted: 02/03/2004] [Indexed: 12/29/2022]
Abstract
The ability of repeated D-amphetamine (2 mg/kg) treatment to induce behavioral sensitization in rats and alter glial fibrillary acidic protein (GFAP), dopamine transporter (DAT) and glutamate transporter-1 (GLT-1) immunoreactivities was assessed after a 10-day drug abstinence period. Results showed that a sensitizing regimen of amphetamine caused a persistent increase in the number of GFAP-positive cells in the dorsal and ventral caudate-putamen. DAT and GLT-1 immunoreactivities were unaffected. Although the elevated GFAP expression may be due to a mild neurotoxicity, it is also possible that amphetamine-induced increases in GFAP reflect adaptive changes that may be associated with processes underlying behavioral sensitization.
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Affiliation(s)
- Victoria Armstrong
- Department of Psychology, California State University, San Bernardino, CA 92407, USA
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17
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Adell A, Artigas F. The somatodendritic release of dopamine in the ventral tegmental area and its regulation by afferent transmitter systems. Neurosci Biobehav Rev 2004; 28:415-31. [PMID: 15289006 DOI: 10.1016/j.neubiorev.2004.05.001] [Citation(s) in RCA: 121] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2004] [Revised: 05/12/2004] [Accepted: 05/12/2004] [Indexed: 10/26/2022]
Abstract
The release of dopamine in the ventral tegmental area (VTA) plays an important role in the autoinhibition of the dopamine neurons of the mesocorticolimbic system through the activation of somatodendritic dopamine D2 autoreceptors. Accordingly, the intra-VTA application of dopamine D2 receptor agonists reduces the firing rate and release of dopamine in the VTA, and this control appears to possess a tonic nature because the corresponding antagonists enhance the somatodendritic release of the transmitter. In addition, the release of dopamine in the VTA is increased by potassium or veratridine depolarization and abolished by tetrodotoxin and calcium omission. Overall, it appears that the somatodendritic release of dopamine is consistently lower than that in nerve endings. Apart from intrinsic dopaminergic mechanisms, other transmitter systems such as serotonin, noradrenaline, acetylcholine, GABA and glutamate play a role in the control of the activity of dopaminergic neurons of the VTA, although the final action depends on the particular receptor involved as well as the neuronal type where it is localized. Given the involvement of the mesocorticolimbic dopaminergic systems in the pathogenesis of severe neuropsychiatric disorders such as schizophrenia, the knowledge of the factors that regulate the release of dopamine in the VTA could provide new insight into the ethiogenesis of the disease as well as its implication on the mechanisms of action of therapeutic drugs.
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Affiliation(s)
- Albert Adell
- Department of Neurochemistry, Institut d'Investigacions Biomèdiques de Barcelona, CSIC (IDIBAPS), Carrer Rosselló 161, 6th floor, E-08036 Barcelona, Spain.
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18
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Moroz IA, Peciña S, Schallert T, Stewart J. Sparing of behavior and basal extracellular dopamine after 6-hydroxydopamine lesions of the nigrostriatal pathway in rats exposed to a prelesion sensitizing regimen of amphetamine. Exp Neurol 2004; 189:78-93. [PMID: 15296838 DOI: 10.1016/j.expneurol.2004.05.012] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2003] [Revised: 05/01/2004] [Accepted: 05/07/2004] [Indexed: 11/20/2022]
Abstract
Repeated administration of amphetamine leads to enduring augmentation of its behavioral-activating effects, enhanced dopamine (DA) release in striatal regions, and morphological changes in DA target neurons. Here we show that exposure to a 2-week escalating-dose regimen of amphetamine prevents behavioral asymmetries of forelimb use and spontaneous (drug-independent) turning behavior following unilateral 6-hydroxydopamine (6-OHDA) lesions of the nigrostriatal pathway made 7-14 days after termination of amphetamine treatment (Experiments 1-3). Exposure to three nonescalating injections of amphetamine 7 days before 6-OHDA lesions had no effect (Experiment 2). Prelesion amphetamine treatment led to normalization of basal extracellular levels of striatal DA as measured by microdialysis on days 11-14 and 25-28 after lesioning (Experiment 3). However, there were no significant differences between treatment groups in postmortem tissue levels of DA and its metabolites, indicating a dissociation between the DA depletion and the extracellular levels of DA as measured by microdialysis. Finally, rats exposed to the escalating amphetamine regimen had reduced lesion-induced loss of TH-IR cells in the ipsilateral DA cell body regions (Experiment 3). Thus, prelesion exposure to the escalating doses of amphetamine may render the cells resistant to the consequences of damage after subsequent 6-OHDA lesions, possibly by accelerating the development of compensatory changes in the DA neurons that typically accompany behavioral recovery. The potential role of amphetamine-induced endogenous neurotrophic factors in the behavioral sparing and normalization of basal extracellular DA levels observed after subsequent 6-OHDA lesions is discussed.
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Affiliation(s)
- Isabella Anna Moroz
- Center for Studies in Behavioral Neurobiology, Concordia University, Montreal, PQ, Canada
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19
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Reeves R, Thiruchelvam M, Richfield EK, Cory-Slechta DA. Behavioral sensitization and long-term neurochemical alterations associated with the fungicide triadimefon. Pharmacol Biochem Behav 2004; 76:315-26. [PMID: 14592684 DOI: 10.1016/j.pbb.2003.08.003] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Triadimefon (TDF), a widely used triazole fungicide, blocks reuptake of the neurotransmitter dopamine (DA), similarly to cocaine. Preliminary studies show that intermittent intraperitoneal injections of TDF increase ambulatory and vertical activity across repeated injections [Neurotoxicology (in press)] leading to the hypothesis tested here, that exposure to TDF may influence the development and expression of behavioral sensitization, a model of psychostimulant-induced psychosis. Exposure of adult male C57BL/6 mice to 75 mg/kg i.p. TDF (TDF75) twice a week for 7 weeks increased vertical activity at each injection. Following a 2-week withdrawal period, a TDF challenge to test for expression of behavioral sensitization revealed further increases in vertical activity levels relative to all other conditions. TDF induction/expression of behavioral sensitization was associated with long-term, perhaps permanent modulation of dopaminergic function that included increases in striatal dihydroxyphenylacetic acid (DOPAC) and DA turnover, increases in medial prefrontal cortex (mPFC) dopamine transporter (DAT) binding, as well as decreases in DA D1 and increases in DA D2 and DAT receptor binding that appeared to target the nucleus accumbens shell (NAs) subregion. Thus, TDF exposure may serve as an environmental risk factor for DA system dysfunctions.
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Affiliation(s)
- Ruth Reeves
- Department of Environmental Medicine, University of Rochester School of Medicine and Dentistry, Rochester, NY 14642, USA.
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20
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Abstract
The development of electrochemical recordings with small carbon-fiber electrodes has significantly advanced the understanding of the regulation of catecholamine transmission in various brain areas. Recordings in vivo or in slice preparations monitor diffusion of catecholamine following stimulated synaptic release into the surrounding tissue. This synaptic 'overflow' is defined by the amount of release, by the activity of reuptake, and by the diffusion parameters in brain tissue. Such studies have elucidated the complex regulation of catecholamine release and uptake, and how psychostimulants and anti-psychotic drugs interfere with it. Moreover, recordings with carbon-fiber electrodes from cultured neurons have provided analysis of catecholamine release and its plasticity at the quantal level.
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Affiliation(s)
- Yvonne Schmitz
- Department of Neurology, Columbia Univeristy, New York, NY 10032, USA.
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21
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Alderson HL, Faulconbridge LFH, Gregory LP, Latimer MP, Winn P. Behavioural sensitisation to repeated d-amphetamine: effects of excitotoxic lesions of the pedunculopontine tegmental nucleus. Neuroscience 2003; 118:311-5. [PMID: 12699767 DOI: 10.1016/s0306-4522(03)00152-0] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
The pedunculopontine tegmental nucleus (PPTg) interacts with anatomical systems thought to be involved in mediating sensitisation of the locomotor response to repeated d-amphetamine. The PPTg has direct and indirect connections with the nucleus accumbens and prefrontal cortex, and also influences midbrain dopamine activity through direct projections to substantia nigra and ventral tegmental area. In this experiment, the development of behavioural sensitisation to the locomotor stimulant effects of repeated d-amphetamine was examined in rats bearing excitotoxic lesions of the PPTg, and sham-lesioned controls. Rats were given repeated d-amphetamine (1.5 mg/kg i.p.) treatment in an on-off procedure, with saline and d-amphetamine given on alternate days, such that rats received a total of seven d-amphetamine and seven saline treatments. Locomotor responses were measured in photocell cages. On the first day of d-amphetamine treatment, there was no difference between excitotoxin and sham-lesioned rats. Development of sensitisation to the locomotor stimulant effects of d-amphetamine was delayed in PPTg-lesioned rats, relative to the sham-lesioned control rats. However, there was no difference between lesion and control groups in the locomotion seen on saline-treatment days. These data suggest that the PPTg is involved in the development of behavioural sensitisation to the locomotor stimulant effects of repeated d-amphetamine, and indicate that traditional striatal circuitry models of the mechanisms underlying sensitisation should be extended to include the PPTg.
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Affiliation(s)
- H L Alderson
- School of Psychology, University of St Andrews, St Andrews, Fife, KY16 9JU, UK.
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22
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Bello NT, Sweigart KL, Lakoski JM, Norgren R, Hajnal A. Restricted feeding with scheduled sucrose access results in an upregulation of the rat dopamine transporter. Am J Physiol Regul Integr Comp Physiol 2003; 284:R1260-8. [PMID: 12521926 DOI: 10.1152/ajpregu.00716.2002] [Citation(s) in RCA: 83] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Recent studies suggest that the mesoaccumbens dopamine system undergoes neurochemical alterations as a result of restricted feeding conditions with access to sugars. This effect appears to be similar to the neuroadaptation resulting from drugs of abuse and may underlay some pathological feeding behaviors. To further investigate the cellular mechanisms of these alterations, the present study used quantitative autoradiography and in situ hybridization to assess dopamine membrane transporter (DAT) protein density and mRNA expression in restricted-fed and free-fed adult male rats. The restricted feeding regimen consisted of daily limited access to either a normally preferred sucrose solution (0.3 M) or a less preferred chow in a scheduled (i.e., contingent) fashion for 7 days. Restricted-fed rats with the contingent sucrose access lost less body weight, ate more total food, and drank more fluid than free-fed, contingent food, or noncontingent controls. In addition, these animals had selectively higher DAT binding in the nucleus accumbens and ventral tegmental area. This increase in protein binding also was accompanied by an increase in DAT mRNA levels in the ventral tegmental area. In contrast to the restricted-fed groups, no differential effect in DAT regulation was observed across free-fed groups. The observed alteration in behavior and DAT regulation suggest that neuroadaptation in the mesoaccumbens dopamine system develops in response to repeated feeding on palatable foods under dietary constraints. This supports the notion that similar cellular changes may be involved in restrictive eating disorders and bingeing.
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Affiliation(s)
- Nicholas T Bello
- Departments of Behavioral Science and of Pharmacology, Neuroscience Graduate Program, Integrative Biosciences Graduate Program, The Pennsylvania State University, College of Medicine, Hershey, Pennsylvania 17033, USA
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23
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Abstract
Dopamine in the nucleus accumbens has been implicated in motivated behavior, including feeding. Normal feeding occurs in patterns, but little is known about how these schedules influence this neural system. We hypothesized that repeated access to preferred foods would augment dopamine clearance. Rats on a restricted feeding schedule had access to 0.3 M sucrose or water followed 2 h later by chow. The rats were kept on this regimen for 7 days, with microdialysis performed on the last day. During the chow period, dopamine turnover in the nucleus accumbens was higher when preceded by sucrose than by water. This finding suggests that, under some dietary conditions, neuroadaptation occurs in response to feeding and these changes may, in turn, influence future meals.
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Affiliation(s)
- Andras Hajnal
- Department of Behavioral Science, The Pennsylvania State University, College of Medicine, Hershey, PA 17033, USA.
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24
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Quadros IMH, Nobrega JN, Hipólide DC, de Lucca EM, Souza-Formigoni MLO. Differential propensity to ethanol sensitization is not associated with altered binding to D1 receptors or dopamine transporters in mouse brain. Addict Biol 2002; 7:291-9. [PMID: 12126488 DOI: 10.1080/13556210220139505] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Behavioral sensitization to ethanol's stimulant effect has been proposed as a marker for individual abuse liability. In previous work we have demonstrated that mice showing an increased propensity to EtOH sensitization had higher levels of dopamine (DA) D2 receptor binding in localized brain areas compared to mice showing less sensitization. In the present study we examined whether altered binding to D1 or the DA transporter (DAT) might also be associated with differential propensity to develop EtOH sensitization. Male Swiss mice received 2.4 g/kg EtOH or saline intraperitoneally (i.p.) daily for 21 days, were tested weekly for locomotor activity, and then sacrificed. D1 and DAT binding were assessed by quantitative autoradiography using [(3)H]SCH-23390 and [(3)H]WIN 35,428, respectively. EtOH-treated mice were subdivided into sensitized and non-sensitized subgroups according to their locomotor activity during treatment. Analyses of brain D1 (19 regions) and DAT (12 regions) binding densities revealed no significant differences among EtOH-sensitized, -non-sensitized or saline groups in any of the regions measured (all p values > 0.32 for D1 and > 0.16 for DAT). These results suggest that brain D1 and DAT binding, unlike the recently reported changes in D2 binding, do not differentiate mice that develop behavioral sensitization to ethanol from those that do not.
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Affiliation(s)
- Isabel M H Quadros
- Department of Psychobiology, Federal University of São Paulo (UNIFESP), São Paulo, Brazil
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25
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Ujike H, Takaki M, Kodama M, Kuroda S. Gene expression related to synaptogenesis, neuritogenesis, and MAP kinase in behavioral sensitization to psychostimulants. Ann N Y Acad Sci 2002; 965:55-67. [PMID: 12105085 DOI: 10.1111/j.1749-6632.2002.tb04151.x] [Citation(s) in RCA: 102] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The most important characteristic of behavioral sensitization to psychostimulants, such as amphetamine and cocaine, is the very long-lasting hypersensitivity to the drug after cessation of exposure. Rearrangement and structural modification of neural networks in CNS must be involved in behavioral sensitization. Previous microscopic studies have shown that the length of dendrites and density of dendritic spines increased in the nucleus accumbens and frontal cortex after repeated exposure to amphetamine and cocaine, but the molecular mechanisms responsible are not well understood. We investigated a set of genes related to synaptogenesis, neuritogenesis, and mitogen-activated protein (MAP) kinase after exposure to methamphetamine. Synaptophysin mRNA, but not VAMP2 (synaptobrevin 2) mRNA, which are considered as synaptogenesis markers, increased in the accumbens, striatum, hippocampus, and several cortices, including the medial frontal cortex, after a single dose of 4 mg/kg methamphetamine. Stathmin mRNA, but not neuritin or narp mRNA, which are markers for neuritic sprouting, increased in the striatum, hippocampus, and cortices after a single dose of methamphetamine. The mRNA of arc, an activity-regulated protein associated with cytoskeleton, but not of alpha-tubulin, as markers for neuritic elongation, showed robust increases in the striatum, hippocampus, and cortices after a single dose of methamphetamine. The mRNAs of MAP kinase phosphatase-1 (MKP-1), MKP-3, and rheb, a ras homologue abundant in brain, were investigated to assess the MAP kinase cascades. MKP-1 and MKP-3 mRNAs, but not rheb mRNA, increased in the striatum, thalamus, and cortices, and in the striatum, hippocampus, and cortices, respectively, after a single methamphetamine. Synaptophysin and stathmin mRNAs did not increase again after chronic methamphetamine administration, whereas the increases in arc, MKP-1, and MKP-3 mRNAs persisted in the brain regions after chronic methamphetamine administration. These findings indicate that the earlier induction process in behavioral sensitization may require various plastic modifications, such as synaptogenesis, neuritic sprouting, neuritic elongation, and activation of MAP kinase cascades, throughout almost the entire brain. In contrast, later maintenance process of sensitization may require only limited plastic modification in restricted regions.
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Affiliation(s)
- Hiroshi Ujike
- Department of Neuropsychiatry, Okayama University Medical School and Graduate School of Medicine and Dentistry, Okayama, Japan.
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26
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Olsen CM, Duvauchelle CL. Intra-prefrontal cortex injections of SCH 23390 influence nucleus accumbens dopamine levels 24 h post-infusion. Brain Res 2001; 922:80-6. [PMID: 11730704 DOI: 10.1016/s0006-8993(01)03152-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
The dopaminergic pathway from the ventral tegmental area (VTA) to the nucleus accumbens (NAcc) is well known to be involved in the reinforcing properties of many drugs of abuse. The medial prefrontal cortex (mPFC) has been shown to exhibit significant influence over activity in this pathway, and has also been implicated in drug abuse. The present experiment investigated the ability of D1 activity in the mPFC to influence accumbal dopamine levels. NAcc dopamine (DA) was monitored before, immediately after, and 24 h following mPFC infusion of a D1 agonist (SKF 38393), D1 antagonist (SCH 23390), or a vehicle solution. Immediately following infusion of dopaminergic agents or vehicle, no significant changes in accumbal DA were observed. However, 24 h following infusion of the antagonist but not the agonist, significant elevations of accumbal DA were observed. Since elevated NAcc DA was only observed 24 h after treatment, these results provide evidence that long-term neural adaptations can be induced by transient neuropharmacological treatment.
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Affiliation(s)
- C M Olsen
- College of Pharmacy, Division of Pharmacology/Toxicology, The University of Texas at Austin, Austin, TX 78712-1074, USA
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27
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Zahniser NR, Doolen S. Chronic and acute regulation of Na+/Cl- -dependent neurotransmitter transporters: drugs, substrates, presynaptic receptors, and signaling systems. Pharmacol Ther 2001; 92:21-55. [PMID: 11750035 DOI: 10.1016/s0163-7258(01)00158-9] [Citation(s) in RCA: 219] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Na+/Cl- -dependent neurotransmitter transporters, which constitute a gene superfamily, are crucial for limiting neurotransmitter activity. Thus, it is critical to understand their regulation. This review focuses primarily on the norepinephrine transporter, the dopamine transporter, the serotonin transporter, and the gamma-aminobutyric acid transporter GAT1. Chronic administration of drugs that alter neurotransmitter release or inhibit transporter activity can produce persistent compensatory changes in brain transporter number and activity. However, regulation has not been universally observed. Transient alterations in norepinephrine transporter, dopamine transporter, serotonin transporter, and GAT1 function and/or number occur in response to more acute manipulations, including membrane potential changes, substrate exposure, ethanol exposure, and presynaptic receptor activation/inhibition. In many cases, acute regulation has been shown to result from a rapid redistribution of the transporter between the cell surface and intracellular sites. Second messenger systems involved in this rapid regulation include protein kinases and phosphatases, of which protein kinase C has been the best characterized. These signaling systems share the common characteristic of altering maximal transport velocity and/or cell surface expression, consistent with regulation of transporter trafficking. Although less well characterized, arachidonic acid, reactive oxygen species, and nitric oxide also alter transporter function. In addition to post-translational modifications, cytoskeleton interactions and transporter oligomerization regulate transporter activity and trafficking. Furthermore, promoter regions involved in transporter transcriptional regulation have begun to be identified. Together, these findings suggest that Na+/Cl- -dependent neurotransmitter transporters are regulated both long-term and in a more dynamic manner, thereby providing several distinct mechanisms for altering synaptic neurotransmitter concentrations and neurotransmission.
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Affiliation(s)
- N R Zahniser
- Department of Pharmacology, C-236, University of Colorado Health Sciences Center, 4200 East Ninth Avenue, Denver, CO 80262, USA.
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28
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Rothblat DS, Schroeder JA, Schneider JS. Tyrosine hydroxylase and dopamine transporter expression in residual dopaminergic neurons: potential contributors to spontaneous recovery from experimental Parkinsonism. J Neurosci Res 2001; 65:254-66. [PMID: 11494360 DOI: 10.1002/jnr.1149] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
1-Methyl-4-phenyl-1,2,3,6-tetrahyrdropyridine (MPTP)-exposed cats develop severe Parkinsonism that spontaneously resolves in 4-6 weeks. The present study examined the extent to which compensatory changes in tyrosine hydroxylase (TH) and dopamine transporter (DAT) gene and protein expression may underlie this behavioral recovery. In normal cats, TH and DAT protein levels were higher in the dorsal vs. ventral striatum. Expression of DAT and TH mRNA was higher in substantia nigra pars compacta (SNc) than in the ventral tegmental area (VTA). In symptomatic parkinsonian animals, DAT and TH protein levels were significantly decreased in all striatal areas studied. TH and DAT mRNA expression in residual SNc neurons were decreased a mean 32% and 38%, respectively. DAT gene expression in residual VTA neurons in symptomatic animals was decreased 30% whereas TH gene expression was unaffected. In spontaneously recovered cats, TH protein levels were significantly higher than the levels in symptomatic cats only in the ventral striatum, whereas no increase in DAT protein levels were observed in any striatal area. Residual neurons in most ventral mesencephalic regions of recovered cats had increased TH mRNA expression but not increased DAT gene expression, compared with symptomatic animals. Thus, increased TH protein and mRNA and suppression of DAT protein and mRNA expression in the striatum and ventral mesencephalon were associated with functional recovery from MPTP-induced parkinsonism.
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Affiliation(s)
- D S Rothblat
- Department of Pathology, Anatomy and Cell Biology, Thomas Jefferson University, 1020 Locust Street, Philadelphia, PA 19107, USA
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29
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Sproson EJ, Chantrey J, Hollis C, Marsden CA, Fonel KC. Effect of repeated methylphenidate administration on presynaptic dopamine and behaviour in young adult rats. J Psychopharmacol 2001; 15:67-75. [PMID: 11448090 DOI: 10.1177/026988110101500202] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Methylphenidate, a dopamine reuptake inhibitor, is the most common treatment for attention-deficit hyperactivity disorder and may be prescribed for years, despite little evidence of any long-term benefit, nor knowledge of potential chronic side-effects. Therefore, this study examined the acute and longer-term behavioural effects and assessed striatal dopamine function following subchronic methylphenidate administration to adolescent rats. Male hooded Lister rats received methylphenidate (4 mg/kg i.p. twice daily for 4 days) or saline (1 ml/kg) and the acute locomotor and stereotype behaviour was monitored on days 1 and 4, novel object exploration on day 2 and, following 12 days drug withdrawal, the long-term effect examined on social interaction on day 16. Ex-vivo K+ (20 mM)- and methylphenidate (0.1 mM)-induced [3H]dopamine release from striatal slices and striatal monoamine content were measured on day 18. Compared with saline, methylphenidate induced mild hyperactivity without stereotypy but did not alter novel object exploration and, following withdrawal, had no long-term effect on social interaction. In striatal slices from controls, both K+ and methylphenidate elevated [3H]dopamine release (p < 0.01) while only combined treatment elevated release in methylphenidate pretreated rats, although striatal monoamine content was unaltered compared with control rats. In summary, a repeated dose of methylphenidate that had acute behavioural effects produced no long-term alteration in social interaction but attenuated presynaptic striatal dopamine function.
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Affiliation(s)
- E J Sproson
- School of Biomedical Sciences, Queen's Medical Centre, Nottingham University, UK
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30
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Rothblat DS, Rubin E, Schneider JS. Effects of chronic alcohol ingestion on the mesostriatal dopamine system in the rat. Neurosci Lett 2001; 300:63-6. [PMID: 11207375 DOI: 10.1016/s0304-3940(01)01548-8] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The effects of chronic alcohol use on the mesostriatal dopamine (DA) system remain relatively unknown. The aim of the present study was to assess multiple measures of the status of the mesostriatal DA system in rats chronically fed an alcohol diet for approximately 1 year. Tissue levels of DA and its metabolite, 3,4-dihydroxyphenylacetic acid, were significantly decreased in both the dorsal striatum (34 and 33%, respectively) and ventral striatum (33 and 36%, respectively) in alcohol-fed rats compared to pair-fed matched controls. Western blotting revealed a mean 20% decrease in tyrosine hydroxylase protein levels in the dorsal and ventral striatum of alcohol-fed animals while dopamine transporter protein levels from the same animals were significantly increased compared to controls (mean 60% increase for the dorsal and ventral striatum). The present results demonstrate significant alterations in the mesostriatal DA system after 1 year of chronic alcohol use. It is possible that the observed changes in DA synthesis and re-uptake measures result in altered intracellular and extracellular DA levels, perhaps contributing to the addictive properties of alcohol.
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Affiliation(s)
- D S Rothblat
- Department of Pathology, Anatomy and Cell Biology, Thomas Jefferson University, Philadelphia, PA 19107, USA
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31
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Do Régo JC, Syringas M, Leblond B, Costentin J, Bonnet JJ. Recovery of dopamine neuronal transporter but lack of change of its mRNA in substantia nigra after inactivation by a new irreversible inhibitor characterized in vitro and ex vivo in the rat. Br J Pharmacol 1999; 128:51-60. [PMID: 10498834 PMCID: PMC1571617 DOI: 10.1038/sj.bjp.0702784] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
1. In vitro, the ability of DEEP-NCS {1-[2-(diphenylmethoxy)ethyl]-4-[2-(4-isothiocyanatophenyl)ethyl]- piperazine} to inhibit [3H]-dopamine uptake by rat striatal synaptosomes was concentration-dependent and inversely related to the protein concentration. This inhibition was irreversible and resulted from changes in Vmax and KM. DEEP-NCS was less potent on noradrenaline, serotonin and choline transport. 2. One day after intrastriatal injections of DEEP-NCS (100 and 1000 pmol) in 20% dimethylsulphoxide, moderate decreases in the ex vivo dopamine uptake were observed in synaptosomes obtained from striatum injected with DEEP-NCS or solvent, and the contralateral uninjected striatum. 3. In similar conditions, 300 pmol DEEP-NCS in 45% 2 hydroxypropyl-gamma-cyclodextrin - 0.5% dimethylsulphoxide solution sub-totally reduced ex vivo dopamine uptake and mazindol binding, and moderately decreased choline and serotonin transport. These reductions were specific to DEEP-NCS-injected striata. A clomipramine pretreatment (16 mg kg-1 i.p. 1 h before) was performed in following experiments, since it reduced the DEEP-NCS-elicited decrease in serotonin uptake without affecting other indices. 4. One day after intrastriatal injection, DEEP-NCS elicited similar dose-dependent decreases in ex vivo dopamine uptake and mazindol binding (ID50=6.9-8 ng striatum-1). Changes in KM and Vmax for ex vivo dopamine transport produced by DEEP-NCS disappeared according to similar time-courses. 5. The t(1/2) for transporter recovery was 6. 1 days. This value should correspond to its actual turnover rate in vivo, since no change in transporter mRNA level was observed in substantia nigra ipsilateral to 300 pmol DEEP-NCS-injected striatum. 6. The results indicate that DEEP-NCS behaves as a potent, quite selective, irreversible inhibitor of the DAT, in vitro and in vivo. Its use in vivo suggests that the physiological half-life of the rat striatal DAT is close to 6 days.
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Affiliation(s)
- Jean-Claude Do Régo
- UPRESA C.N.R.S. 6036, IFRMP 23, Site Universitaire du Madrillet U.F.R. de Médecine & Pharmacie, 76800, Saint Etienne du Rouvray, France
| | - Maria Syringas
- UPRESA C.N.R.S. 6036, IFRMP 23, Site Universitaire du Madrillet U.F.R. de Médecine & Pharmacie, 76800, Saint Etienne du Rouvray, France
| | - Bertrand Leblond
- Centre Européen de Bioprospective, 24 bis rue J. Boutrolle, 76131 Mont Saint Aignan Cedex, France
| | - Jean Costentin
- UPRESA C.N.R.S. 6036, IFRMP 23, Site Universitaire du Madrillet U.F.R. de Médecine & Pharmacie, 76800, Saint Etienne du Rouvray, France
| | - Jean-Jacques Bonnet
- UPRESA C.N.R.S. 6036, IFRMP 23, Site Universitaire du Madrillet U.F.R. de Médecine & Pharmacie, 76800, Saint Etienne du Rouvray, France
- Author for correspondence:
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Affiliation(s)
- F J White
- Department of Neuroscience, Finch University of Health Sciences, Chicago Medical School, North Chicago, IL, USA
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