1
|
Potential roles of 5-HT 3 receptor (5-HT 3R) antagonists in modulating the effects of nicotine. Biomed Pharmacother 2019; 112:108630. [PMID: 30797147 DOI: 10.1016/j.biopha.2019.108630] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2018] [Revised: 01/17/2019] [Accepted: 01/28/2019] [Indexed: 12/22/2022] Open
Abstract
5-HT3R antagonists such as ondansetron, granisetron and tropisetron have been clinically used to treat nausea and vomiting in chemotherapy patients. However, current study and research revealed novel potentials of these ligands in other diseases like inflammation, Alzheimer's, and drug abuse. Towards utilising these drugs as anti-smoking agents to treat nicotine dependence problem, there are conflicting reports regarding the potential of these ligands in modulating the effects of nicotine in both human and animal behavioural studies. This is complicated by the heterogeneity of 5-HT3R itself, cross regulation between nicotinic acetylcholinergic receptor (nAChR) and distinct pharmacological profiles of 5-HT3R antagonists. This review gathered existing studies conducted investigating the potential of "-setron" class of 5-HT3R antagonists in modulating nicotine effects. We proposed that the mechanism where 5-HT3R antagonists mediate the effects of nicotine could be attributed by both direct at 5-HT3R and indirect mechanism in nicotine addiction downstream regulation. The indirect mechanism mediated by the 5-HT3R antagonist could be through α7 nAChR, 5-HT1B receptor (5-HT1BR), 5-HT1C receptor (5-HT1CR), calcineurin activity, p38 MAPK level, PPAR-γ and NF-κβ. Our review suggested that future studies should focus on newer 5-HT3R antagonist with superior pharmacological profile or the one with multitarget action rather than high selectivity at single receptor.
Collapse
|
2
|
The role of serotonin in drug use and addiction. Behav Brain Res 2014; 277:146-92. [PMID: 24769172 DOI: 10.1016/j.bbr.2014.04.007] [Citation(s) in RCA: 208] [Impact Index Per Article: 20.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2014] [Revised: 04/04/2014] [Accepted: 04/05/2014] [Indexed: 12/26/2022]
Abstract
The use of psychoactive drugs is a wide spread behaviour in human societies. The systematic use of a drug requires the establishment of different drug use-associated behaviours which need to be learned and controlled. However, controlled drug use may develop into compulsive drug use and addiction, a major psychiatric disorder with severe consequences for the individual and society. Here we review the role of the serotonergic (5-HT) system in the establishment of drug use-associated behaviours on the one hand and the transition and maintenance of addiction on the other hand for the drugs: cocaine, amphetamine, methamphetamine, MDMA (ecstasy), morphine/heroin, cannabis, alcohol, and nicotine. Results show a crucial, but distinct involvement of the 5-HT system in both processes with considerable overlap between psychostimulant and opioidergic drugs and alcohol. A new functional model suggests specific adaptations in the 5-HT system, which coincide with the establishment of controlled drug use-associated behaviours. These serotonergic adaptations render the nervous system susceptible to the transition to compulsive drug use behaviours and often overlap with genetic risk factors for addiction. Altogether we suggest a new trajectory by which serotonergic neuroadaptations induced by first drug exposure pave the way for the establishment of addiction.
Collapse
|
3
|
Brennan KA, Putt F, Truman P. Nicotine-, tobacco particulate matter- and methamphetamine-produced locomotor sensitisation in rats. Psychopharmacology (Berl) 2013; 228:659-72. [PMID: 23519574 DOI: 10.1007/s00213-013-3071-3] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/03/2013] [Accepted: 03/08/2013] [Indexed: 12/18/2022]
Abstract
RATIONALE Repeated nicotine exposure produces a weak and transient sensitised locomotor response in rats. Since tobacco smoke contains thousands of non-nicotine chemical constituents, these could alter the sensitised response. OBJECTIVES This study aims to compare the magnitude, persistence and spatial distribution of locomotor sensitisation produced by repeated doses of nicotine, aqueous tobacco particulate matter (TPM) and a positive methamphetamine control. METHODS Male Sprague-Dawley rats received five nicotine (0.0, 0.2 or 0.4 mg/kg), TPM (containing 0.2 or 0.4 mg/kg nicotine) or methamphetamine (0.5 mg/kg) injections every second day, followed by a 4-day withdrawal before the first challenge (Challenge 1, C1). The animals were re-challenged again at 15 days post C1 to test for the persistence of sensitisation (Challenge 2, C2). RESULTS There were no major differences in sensitisation profile between nicotine and TPM. At the lowest 0.2 mg/kg nicotine/TPM dose, however, small differences emerged on select test days. CONCLUSIONS The results indicated that the non-nicotinic agents in TPM did not greatly impact the nicotine-produced locomotor-sensitised response. These findings might suggest that the differential pharmacological properties of TPM do not have major clinical significance. Alternatively, the locomotor model might not expose effects of non-nicotinic constituents, and furthermore, might not closely relate to human tobacco dependence. Different reward-related behavioural models should also be utilised to assess potential effects of non-nicotinic constituents before a role in dependence is discounted.
Collapse
Affiliation(s)
- Katharine A Brennan
- School of Psychology, Victoria University of Wellington, P.O. Box 600, Wellington, 6140, New Zealand.
| | | | | |
Collapse
|
4
|
Müller CP, Pum ME, Schumann G, Huston JP. The Role of Serotonin in Drug Addiction. HANDBOOK OF BEHAVIORAL NEUROSCIENCE 2010. [DOI: 10.1016/s1569-7339(10)70099-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
|
5
|
Hayes DJ, Mosher TM, Greenshaw AJ. Differential effects of 5-HT2C receptor activation by WAY 161503 on nicotine-induced place conditioning and locomotor activity in rats. Behav Brain Res 2009; 197:323-30. [DOI: 10.1016/j.bbr.2008.08.034] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2008] [Revised: 08/21/2008] [Accepted: 08/26/2008] [Indexed: 10/21/2022]
|
6
|
Engleman EA, Rodd ZA, Bell RL, Murphy JM. The role of 5-HT3 receptors in drug abuse and as a target for pharmacotherapy. CNS & NEUROLOGICAL DISORDERS DRUG TARGETS 2008; 7:454-67. [PMID: 19128203 PMCID: PMC2878195 DOI: 10.2174/187152708786927886] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Alcohol and drug abuse continue to be a major public health problem in the United States and other industrialized nations. Extensive preclinical research indicates the mesolimbic dopamine (DA) pathway and associated regions mediate the rewarding and reinforcing effects of drugs of abuse and natural rewards, such as food and sex. The serotonergic (5-HT) system, in concert with others neurotransmitter systems, plays a key role in modulating neuronal systems within the mesolimbic pathway. A substantial portion of this modulation is mediated by activity at the 5-HT3 receptor. The 5-HT3 receptor is unique among the 5-HT receptors in that it directly gates an ion channel inducing rapid depolarization that, in turn, causes the release of neurotransmitters and/or peptides. Preclinical findings indicate that antagonism of the 5-HT3 receptor in the ventral tegmental area, nucleus accumbens or amygdala reduces alcohol self-administration and/or alcohol-associated effects. Less is known about the effects of 5-HT3 receptor activity on the self-administration of other drugs of abuse or their associated effects. Clinical findings parallel the preclinical findings such that antagonism of the 5-HT3 receptor reduces alcohol consumption and some of its subjective effects. This review provides an overview of the structure, function, and pharmacology of 5-HT3 receptors, the role of these receptors in regulating DA neurotransmission in mesolimbic brain areas, and discusses data from animal and human studies implicating 5-HT3 receptors as targets for the development of new pharmacological agents to treat addictions.
Collapse
Affiliation(s)
- E A Engleman
- Indiana University School of Medicine, Department of Psychiatry, Institute of Psychiatric Research, 791 Union Drive, Indianapolis, IN 46202, USA.
| | | | | | | |
Collapse
|
7
|
Silverstone P, Greenshaw A. Section Review Central & Peripheral Nervous Systems: 5-HT3receptor antagonists. Expert Opin Ther Pat 2008. [DOI: 10.1517/13543776.6.5.471] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
|
8
|
Lerman C, LeSage MG, Perkins KA, O'Malley SS, Siegel SJ, Benowitz NL, Corrigall WA. Translational research in medication development for nicotine dependence. Nat Rev Drug Discov 2007; 6:746-62. [PMID: 17690709 DOI: 10.1038/nrd2361] [Citation(s) in RCA: 128] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
A major obstacle to the development of medications for nicotine dependence is the lack of animal and human laboratory models with sufficient predictive clinical validity to support the translation of knowledge from laboratory studies to clinical research. This Review describes the animal and human laboratory paradigms commonly used to investigate the pathophysiology of nicotine dependence, and proposes how their predictive validity might be determined and improved, thereby enhancing the development of new medications.
Collapse
Affiliation(s)
- Caryn Lerman
- Department of Psychiatry and Abramson Cancer Center, University of Pennsylvania, 3535 Market Street, Suite 4100, Philadelphia, Pennsylvania 19104, USA.
| | | | | | | | | | | | | |
Collapse
|
9
|
Mosher TM, Smith JG, Greenshaw AJ. Aversive stimulus properties of the 5-HT2C receptor agonist WAY 161503 in rats. Neuropharmacology 2006; 51:641-50. [PMID: 16844150 DOI: 10.1016/j.neuropharm.2006.05.006] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2006] [Revised: 05/03/2006] [Accepted: 05/04/2006] [Indexed: 11/19/2022]
Abstract
Serotonin2C (5-HT2C) receptors may influence motivation and reward through effects on the mesocorticolimbic dopamine (DA) system. Previous work from this laboratory indicated that 5-HT2C receptor stimulation does not induce place conditioning when animals are tested in a drug-free state, but does result in decreased locomotor activity and increased frequency thresholds for electrical self-stimulation of the ventral tegmental area (VTA). The present study was conducted to determine whether the 5-HT2C receptor agonist WAY 161503 may induce place conditioning in a state-dependent manner and also whether this compound will induce gustatory avoidance conditioning in the conditioned taste aversion (CTA) paradigm. The effects of the 5-HT2C receptor agonist WAY 161503 in the place conditioning and CTA (two-bottle choice test) paradigms were assessed in male Sprague-Dawley rats. Administration of WAY 161503 (3.0 mg/kg) induced a state-dependent conditioned place aversion and a CTA to saccharin. The differential state dependency of 5-HT2C receptor agonists' effects in place conditioning (state dependent) and CTA (non-state dependent) is consistent with the activation of different brain systems in these two paradigms. The state-dependent effects in place conditioning underscore the need to include controls for state dependency in studies of 5-HT receptor related compounds.
Collapse
Affiliation(s)
- T M Mosher
- W.G. Dewhurst Laboratory, Neurochemical Research Unit, Department of Psychiatry and Centre for Neuroscience, 1E7.44 WMHSC, University of Alberta, Edmonton, AB, T6G 2R7, Canada
| | | | | |
Collapse
|
10
|
Lê AD, Funk D, Harding S, Juzytsch W, Fletcher PJ, Shaham Y. Effects of dexfenfluramine and 5-HT3 receptor antagonists on stress-induced reinstatement of alcohol seeking in rats. Psychopharmacology (Berl) 2006; 186:82-92. [PMID: 16521030 DOI: 10.1007/s00213-006-0346-y] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/29/2005] [Accepted: 02/03/2006] [Indexed: 12/21/2022]
Abstract
RATIONALE AND OBJECTIVES We previously found that systemic injections of the 5-HT uptake blocker fluoxetine attenuate intermittent footshock stress-induced reinstatement of alcohol seeking in rats, while inhibition of 5-HT neurons in the median raphe induces reinstatement of alcohol seeking. In this study, we further explored the role of 5-HT in footshock stress-induced reinstatement of alcohol seeking by determining the effects of the 5-HT releaser and reuptake blocker dexfenfluramine, and the 5-HT receptor antagonists ondansetron and tropisetron, which decrease alcohol self-administration and anxiety-like responses in rats, on this reinstatement. METHODS Different groups of male Wistar rats were trained to self-administer alcohol (12% v/v) for 28-31 days (1 h/day, 0.19 ml per alcohol delivery) and then their lever responding for alcohol was extinguished over 9-10 days. Subsequently, the effect of systemic injections of vehicle or dexfenfluramine (0.25 or 0.5 mg/kg, i.p), ondansetron (0.001, 0.01, or 0.1 mg/kg, i.p), or tropisetron (0.001, 0.01, and 0.1 mg/kg, i.p) on reinstatement induced by 10 min of intermittent footshock (0.8 mA) was determined. RESULTS Systemic injections of dexfenfluramine, ondansetron or tropisetron attenuated footshock-induced reinstatement of alcohol seeking. Injections of dexfenfluramine, ondansetron, or tropisetron had no effect on extinguished lever responding in the absence of footshock. CONCLUSIONS The present results provide additional support for the hypothesis that brain 5-HT systems are involved in stress-induced reinstatement of alcohol seeking. The neuronal mechanisms that potentially mediate the unexpected observation that both stimulation of 5-HT release and blockade of 5-HT3 receptors attenuate footshock-induced reinstatement are discussed.
Collapse
Affiliation(s)
- Anh Dzung Lê
- Department of Neuroscience, Centre for Addiction and Mental Health, 33 Russell Street, Toronto, Ontario, M5S 2S1, Canada.
| | | | | | | | | | | |
Collapse
|
11
|
De Deurwaerdère P, Moison D, Navailles S, Porras G, Spampinato U. Regionally and functionally distinct serotonin3 receptors control in vivo dopamine outflow in the rat nucleus accumbens. J Neurochem 2005; 94:140-9. [PMID: 15953357 DOI: 10.1111/j.1471-4159.2005.03174.x] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Central serotonin(3) (5-HT(3)) receptors control the mesoaccumbens dopamine (DA) pathway. This control is thought to be conditional and might involve regionally distinct subpopulations of 5-HT(3) receptors. Here, using in vivo microdialysis in rats, we assessed the relative contribution of nucleus accumbens (Nacc) 5-HT(3) receptors to the overall influence exerted by 5-HT(3) receptors on accumbal DA release induced by different drugs or treatments. In freely moving rats, pre-treatment with 5-HT(3) antagonists (0.1 mg/kg ondansetron and/or 0.03 mg/kg MDL 72222, s.c.) reduced DA efflux enhanced by morphine (1-10 mg/kg, s.c.) and haloperidol (0.01 mg/kg, s.c.), but not amphetamine (1-2.5 mg/kg, i.p.) or cocaine (10-20 mg/kg, i.p.), the latter two drugs do not trigger depolarization-stimulated DA exocytosis. Intra-Nacc administration of ondansetron (1 microm) in freely moving rats reduced the DA effects elicited by 10 mg/kg morphine, but not 1 mg/kg morphine or haloperidol. The 5-HT(1A) agonist 8-OH-DPAT (0.1 mg/kg, s.c.), known to decrease central 5-HT tone, reduced 10 but not 1 mg/kg morphine-stimulated DA outflow in freely moving rats. In halothane-anaesthetized rats, intra-Nacc ondansetron (1 microm) application reduced dorsal raphe nucleus electrical stimulation (20Hz)-induced DA outflow. Our results show that regionally distinct populations of 5-HT(3) receptors control the depolarization-dependent exocytosis of DA and suggest that the involvement of Nacc 5-HT(3) receptors occurs only when central DA and 5-HT tones are concomitantly increased.
Collapse
Affiliation(s)
- Philippe De Deurwaerdère
- Unité Mixte de Recherche-Centre National de la Recherche Scientifique 5541, Université Victor Segalen Bordeaux 2, France
| | | | | | | | | |
Collapse
|
12
|
Hatsukami DK, Jensen J, Brauer LH, Mooney M, Schulte S, Sofuoglu M, Pentel PR. Lack of effect of 5HT3 antagonist in mediating subjective and behavioral responses to cotinine. Pharmacol Biochem Behav 2003; 75:1-7. [PMID: 12759107 DOI: 10.1016/s0091-3057(03)00035-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Previous studies have shown that cotinine, a metabolite of nicotine, may antagonize some of the therapeutic effects of nicotine. The mechanisms underlying cotinine's effects are unclear, but cotinine has been observed to increase serotonin levels in the brain. Thus, it is possible that blocking serotonin effects may antagonize the actions of cotinine, thereby reducing its impact on responses to nicotine. This study determined whether granisetron, a 5HT(3) receptor antagonist, would enhance the efficacy of the nicotine patch. Subjects were randomly assigned to one of the three granisetron conditions (N=43 for 2 mg/day; N=43 for 1 mg/day; N=42 for 0 mg/day) and asked to take the assigned medication daily during 15 days of tobacco abstinence. Because we were interested in interactions between cotinine and serotonin, all groups were also treated with a 21-mg nicotine patch. Assessments of withdrawal symptoms were made for 1 week during baseline smoking and several times during the experimental period. There was a near but nonsignificant difference among groups on a measure of tobacco withdrawal and no significant differences on global measures of drug effects or physiological measures. The data do not strongly support the hypothesis that 5HT(3) agonism is the mechanism by which cotinine offsets the effects of nicotine.
Collapse
Affiliation(s)
- Dorothy K Hatsukami
- Tobacco Use Research Center, University of Minnesota, 2701 University Avenue, #201, Minneapolis, MN 55414, USA.
| | | | | | | | | | | | | |
Collapse
|
13
|
Olausson P, Engel JA, Söderpalm B. Involvement of serotonin in nicotine dependence: processes relevant to positive and negative regulation of drug intake. Pharmacol Biochem Behav 2002; 71:757-71. [PMID: 11888567 DOI: 10.1016/s0091-3057(01)00673-6] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
The neurobiological substrate of nicotine dependence has been the subject of extensive preclinical and clinical research. Many experimental reports have implicated the brain serotonin (5-HT) systems in processes relevant to nicotine dependence, but the specific role of this neurotransmitter system largely remains to be elucidated. This review will focus on the role of 5-HT in the acute and chronic effects of nicotine. In particular, the evidence for a role of 5-HT neurotransmission in brain processes thought to be involved in positive and negative control of nicotine use will be examined, and potential clinical implications discussed.
Collapse
Affiliation(s)
- Peter Olausson
- Department of Psychiatry, Laboratory of Molecular Psychiatry, Yale University, 34 Park Street, New Haven, CT 06508, USA.
| | | | | |
Collapse
|
14
|
Abstract
This review focuses on nicotinic--serotonergic interactions in the central nervous system (CNS). Nicotine increases 5-hydroxytryptamine (5-HT) release in the cortex, striatum, hippocampus, dorsal raphé nucleus (DRN), hypothalamus, and spinal cord. As yet, there is little firm evidence for nicotinic receptors on serotonergic terminals and thus nicotine's effects on 5-HT may not necessarily be directly mediated, but there is strong evidence that the 5-HT tone plays a permissive role in nicotine's effects. The effects in the cortex, hippocampus, and DRN involve stimulation of 5-HT(1A) receptors, and in the striatum, 5-HT(3) receptors. The 5-HT(1A) receptors in the DRN play a role in mediating the anxiolytic effects of nicotine and the 5-HT(1A) receptors in the dorsal hippocampus and lateral septum mediate its anxiogenic effects. The increased startle and anxiety during nicotine withdrawal is mediated by 5-HT(1A) and 5-HT(3) receptors. The locomotor stimulant effect of acute nicotine is mediated by 5-HT(1A) receptors and 5-HT(2) receptors may play a role in the expression of a sensitised response after chronic nicotine treatment. Unfortunately, the role of 5-HT(1A) receptors in mediating nicotine seeking has not yet been investigated and would seem an important area for future research. There is also evidence for nicotinic--serotonergic interactions in the acquisition of the water maze, passive avoidance, and impulsivity in the five-choice serial reaction task.
Collapse
Affiliation(s)
- Pallab Seth
- Psychopharmacology Research Unit, Centre for Neuroscience, GKT School of Biomedical Sciences, King's College London, Hodgkin Building, Guy's Campus, SE1 1UL, London, UK
| | | | | | | |
Collapse
|
15
|
Alkadhi KA, Otoom SA, Tanner FL, Sockwell D, Hogan YH. Inhibition of ganglionic long-term potentiation decreases blood pressure in spontaneously hypertensive rats. Exp Biol Med (Maywood) 2001; 226:1024-30. [PMID: 11743138 DOI: 10.1177/153537020122601109] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Long-term potentiation of sympathetic ganglia (gLTP), a unique form of synaptic plasticity, is serotonin dependent and can be blocked with 5-HT3 receptor antagonists. Long-lasting enhancement of the basal tone of ganglionic transmission (as with gLTP) is expected to result in sustained increase in peripheral resistance that would lead to elevated blood pressure. We examined the possibility that in sympathetic ganglia, gLTP may be involved in the expression of stress-induced (neurogenic) form of hypertension. High blood pressure in spontaneously hypertensive rat (SHR), known to show exaggerated cardiovascular defense reactions to environmental stimuli, is partly due to a neurogenic factor. Chronic treatment of SHR and their normotensive counterpart, the Wistar Kyoto (WKY) rats with the 5-HT3 receptor antagonist tropisetron (ICS; 5 mg/kg/day), caused a marked decrease in the blood pressure of the SHR but not of WKY rats. Increasing the daily dose of ICS cumulatively (7 and 10 mg/kg) did not result in significant additional decrease in blood pressure of SHR, indicating that the drug blocks only the neurogenic component of hypertension in the SHR. electrophysiological procedures for indirectly testing for the presence of gLTP in ganglia excised from SHR suggest that gLTP has been previously expressed in these ganglia in vivo. This contrasts with the absence of gLTP in ganglia from normotensive rats. The results support contribution of gLTP to the expression of neurogenic hypertension.
Collapse
Affiliation(s)
- K A Alkadhi
- Department of Pharmacological and Pharmaceutical Sciences, University of Houston, Houston, Texas 77204-5515, USA.
| | | | | | | | | |
Collapse
|
16
|
Boye SM, Grant RJ, Clarke PB. Disruption of dopaminergic neurotransmission in nucleus accumbens core inhibits the locomotor stimulant effects of nicotine and D-amphetamine in rats. Neuropharmacology 2001; 40:792-805. [PMID: 11369033 DOI: 10.1016/s0028-3908(01)00003-x] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The locomotor stimulant effects of nicotine and amphetamine appear to be dependent on dopamine transmission in the nucleus accumbens. The present aim was to elucidate the contributions of the accumbens core and medial shell to these effects. In the first experiment, rats received bilateral intra-accumbens infusion of the dopaminergic antagonist eticlopride (or saline) prior to saline or nicotine (0.2 mg/kg s.c.) challenge. Eticlopride inhibited basal and nicotine-induced locomotor activity more effectively when infused into the core (0.0625--0.5 microg/side) than into the medial shell (0.5--1 microg/side). In a second experiment, rats received 6-hydroxydopamine infused into the core or medial shell, and were subsequently tested with saline, nicotine (0.2 mg/kg s.c.) and D-amphetamine (0.75 mg/kg s.c.). Residual dopaminergic innervation was assessed by autoradiographic [(125)I]RTI-55 labelling of the dopamine transporter. [(125)I]RTI-55 labelling in the accumbens core was positively correlated with the locomotor stimulant effects of both nicotine and D-amphetamine. In contrast, [(125)I]RTI-55 labelling in the medial shell was associated negatively with amphetamine-induced activity. Recent evidence suggests that dopamine release in the medial shell may mediate the reinforcing effect of nicotine and D-amphetamine. In contrast, the present findings suggest that dopamine release in the core subregion contributes preferentially to the locomotor stimulant effects of nicotine and D-amphetamine.
Collapse
Affiliation(s)
- S M Boye
- Department of Pharmacology and Therapeutics, McGill University, 3655 Promenade Sir William Osler, Montreal, Quebec, Canada H3G 1Y6.
| | | | | |
Collapse
|