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Madden JT, Reyna NC, Goranson EV, Gonzalez TA, Zavala AR, Pentkowski NS. Blocking serotonin 2A (5-HT 2A) receptors attenuates the acquisition of methamphetamine-induced conditioned place preference in adult female rats. Behav Brain Res 2021; 415:113521. [PMID: 34391796 DOI: 10.1016/j.bbr.2021.113521] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Revised: 07/29/2021] [Accepted: 08/09/2021] [Indexed: 11/19/2022]
Abstract
Methamphetamine withdrawal can induce intense cravings leading to relapse. Contexts/cues paired with chronic methamphetamine use develop incentive motivational properties, promoting future drug-seeking and taking behavior. Research has shown that, in adult male rats, the selective 5-HT2A receptor antagonist M100907 attenuates the acquisition of methamphetamine-induced conditioned place preference (CPP), a measure that examines conditioned associations between the rewarding properties of drugs and contexts. However, these findings have not been extended to adult female rats. The present study investigated the effects of M100907 on the acquisition of methamphetamine-CPP in adult female rats. During conditioning, rats were administered M100907 (0, 0.025, 0.25 mg/kg, i.p.) 15 min before methamphetamine (1 mg/kg, i.p.) and then placed into their initially non-preferred chamber for 30 min, or administered saline and placed into their initially preferred chamber for 30 min. Conditioning sessions were separated by four hours. Following four days of conditioning, the effects of M100907 on the acquisition of methamphetamine-CPP were assessed during a 15 min drug-free test trial. Pretreatment with M100907 dose-dependently attenuated the acquisition of methamphetamine-induced CPP. Blocking 5-HT2A receptors with a low dose of the selective antagonist M100907 attenuated the rewarding effects of methamphetamine in adult female rats. These data provide further evidence that the 5-HT2A receptor subtype is involved in the behavioral effects of methamphetamine.
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Affiliation(s)
- John T Madden
- Department of Psychology, University of New Mexico, Albuquerque, NM, USA
| | - Nicole C Reyna
- Department of Psychology, University of New Mexico, Albuquerque, NM, USA
| | - Emerald V Goranson
- Department of Psychology, University of New Mexico, Albuquerque, NM, USA
| | - Tiffany A Gonzalez
- Department of Psychology, California State University, Long Beach, Long Beach, CA, USA
| | - Arturo R Zavala
- Department of Psychology, California State University, Long Beach, Long Beach, CA, USA
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Arout CA, Cooper ZD, Reed SC, Foltin RW, Comer SD, Levin FR, Haney M. 5HT-2C agonist lorcaserin decreases cannabis self-administration in daily cannabis smokers. Addict Biol 2021; 26:e12993. [PMID: 33389797 DOI: 10.1111/adb.12993] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Revised: 10/27/2020] [Accepted: 11/10/2020] [Indexed: 12/22/2022]
Abstract
There are no FDA-approved treatments for cannabis use disorder (CUD). Preclinical research has shown that the 5HT-2C agonist lorcaserin attenuates cue-induced reinstatement of THC seeking and self-administration. The goal of this placebo-controlled, counterbalanced, within-subject human laboratory study was to examine lorcaserin's effects on cannabis intoxication and self-administration. Lorcaserin (10 mg BID) was administered during one of two 13-day inpatient phases and placebo during the other; each phase was separated by ≥7 days of washout. Inpatient phases comprised (1) standardized cannabis administration (7.0% THC) at no financial cost (intoxication), counterbalanced with (2) the option to self-administer cannabis following either 0 or 3 days of abstinence. Cognitive task performance, food intake, subjective ratings of drug effects, objective/subjective sleep measures, and tobacco cigarette use were also assessed. Fifteen normal-weight, daily cannabis users (4F, 11M) not seeking treatment for CUD completed the study. Lorcaserin significantly reduced cannabis self-administration following 0 and 3 days of cannabis abstinence and also reduced craving for cannabis during abstinence. Lorcaserin produced small but significant increases in positive cannabis ratings and body weight relative to placebo. Lorcaserin also reduced tobacco cigarette smoking on days of cannabis administration relative to placebo. During abstinence, subjective but not objective measures of sleep quality worsened during lorcaserin maintenance. Overall, lorcaserin's ability to decrease drug taking and cannabis craving in nontreatment-seeking cannabis users supports further investigation of 5HT-2C agonists as potential pharmacotherapies for CUD.
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Affiliation(s)
- Caroline A. Arout
- Department of Psychiatry, New York State Psychiatric Institute Columbia University Irving Medical Center New York NY USA
| | - Ziva D. Cooper
- UCLA Cannabis Research Initiative, Jane and Terry Semel Institute for Neuroscience and Human Behavior, Department of Psychiatry and Biobehavioral Sciences University of California, Los Angeles Los Angeles CA USA
| | - Stephanie Collins Reed
- Department of Psychiatry, New York State Psychiatric Institute Columbia University Irving Medical Center New York NY USA
| | - Richard W. Foltin
- Department of Psychiatry, New York State Psychiatric Institute Columbia University Irving Medical Center New York NY USA
| | - Sandra D. Comer
- Department of Psychiatry, New York State Psychiatric Institute Columbia University Irving Medical Center New York NY USA
| | - Frances R. Levin
- Department of Psychiatry, New York State Psychiatric Institute Columbia University Irving Medical Center New York NY USA
| | - Margaret Haney
- Department of Psychiatry, New York State Psychiatric Institute Columbia University Irving Medical Center New York NY USA
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Madden JT, Reyna NC, Pentkowski NS. Antagonizing serotonin 2A (5-HT 2A) receptors attenuates methamphetamine-induced reward and blocks methamphetamine-induced anxiety-like behaviors in adult male rats. Drug Alcohol Depend 2020; 215:108178. [PMID: 32739601 DOI: 10.1016/j.drugalcdep.2020.108178] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/03/2020] [Revised: 06/04/2020] [Accepted: 07/01/2020] [Indexed: 12/13/2022]
Abstract
BACKGROUND Methamphetamine is a highly addictive and abused psychostimulant. Symptoms of methamphetamine withdrawal including drug craving and anxiety that can drive relapse. Currently, there is no FDA approved treatment for methamphetamine use disorder, highlighting the need for research examining the neural mechanisms underlying psychostimulant-induced behaviors. Research indicates that the 5-HT2A receptor antagonist M100907 attenuates several psychostimulant-induced behaviors, including conditioned place preference (CPP). However, these findings have not been extended to methamphetamine. The present study investigated the effects of M100907 on acquisition of methamphetamine-CPP and methamphetamine-induced anxiety-like behavior. METHODS Adult male rats were tested across eight consecutive days. Prior to methamphetamine administration (0 or 1 mg/kg, i.p.), rats were pretreated with their assigned dose of M100907 (0, 0.0025 .025 or 0.25 mg/kg, i.p.) and were placed into their initially non-preferred chamber. After four methamphetamine conditioning sessions, the effects of M100907 on methamphetamine-induced CPP were assessed. Following CPP testing, rats were screened for anxiety-like behaviors in the elevated plus-maze. RESULTS Pretreatment with M100907 attenuated methamphetamine-induced CPP without producing any observable rewarding or aversive effects in methamphetamine naïve rats. Additionally, M100907 blocked methamphetamine-induced increases in anxiety-like behavior and attenuated some indices of anxiety in methamphetamine naïve rats. CONCLUSIONS Results suggest that blocking 5-HT2A receptors with the selective antagonist M100907 attenuates the rewarding effects of methamphetamine and does not produce any rewarding or aversive effects alone. Further, M100907 pretreatment blocked the anxiety-inducing effects of methamphetamine. Collectively, these data suggest that the 5-HT2A receptor subtype represents a novel target for treating methamphetamine use disorder.
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Affiliation(s)
- John T Madden
- Department of Psychology, University of New Mexico, Albuquerque, New Mexico, USA
| | - Nicole C Reyna
- Department of Psychology, University of New Mexico, Albuquerque, New Mexico, USA
| | - Nathan S Pentkowski
- Department of Psychology, University of New Mexico, Albuquerque, New Mexico, USA.
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Abstract
Numerous drugs elicit locomotor stimulant effects at appropriate doses; however, we typically reserve the term psychostimulant to refer to drugs with affinity for monoamine reuptake transporters. This chapter comprises select experiments that have characterized the discriminative stimulus effects of psychostimulants using drug discrimination procedures. The substitution profiles of psychostimulants in laboratory rodents are generally consistent with those observed in human and nonhuman primate drug discrimination experiments. Notably, two major classes of psychostimulants can be distinguished as those that function as passive monoamine reuptake inhibitors (such as cocaine) and those that function as substrates for monoamine transporters and stimulate monoamine release (such as the amphetamines). Nevertheless, the discriminative stimulus effects of both classes of psychostimulant are quite similar, and drugs from different classes will substitute for one another. Most importantly, for both the cocaine-like and amphetamine-like psychostimulants, dopaminergic mechanisms most saliently determine discriminative stimulus effects, but these effects can be modulated by alterations in noradrenergic and serotonergic neurotransmission as well. Thusly, the drug discrimination assay is useful for characterizing the interoceptive effects of psychostimulants and determining the mechanisms that contribute to their subjective effects in humans.
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Affiliation(s)
- Michael D Berquist
- Department of Pharmacology and Toxicology, College of Medicine, University of Arkansas for Medical Sciences, 4301 West Markham Street, Slot 638, Little Rock, AR, 72205, USA
| | - William E Fantegrossi
- Department of Pharmacology and Toxicology, College of Medicine, University of Arkansas for Medical Sciences, 4301 West Markham Street, Slot 638, Little Rock, AR, 72205, USA.
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Shahidi S, Komaki A, Sadeghian R, Soleimani Asl S. Effect of a 5-HT 1D receptor agonist on the reinstatement phase of the conditioned place preference test and hippocampal long-term potentiation in methamphetamine-treated rats. Brain Res 2018; 1698:151-160. [PMID: 30076792 DOI: 10.1016/j.brainres.2018.07.030] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2018] [Revised: 07/26/2018] [Accepted: 07/31/2018] [Indexed: 12/20/2022]
Abstract
Methamphetamine (METH)-seeking relapse is associated with memory and synaptic plasticity changes. Serotonin is a key neuromodulator in this process. While there is a known distribution of 5-HT1D receptors in reward and memory areas, such as the hippocampus, its physiological function is currently unknown. Here, we evaluated effect of a 5-HT1D receptor agonist, PNU142633, on the reinstatement of METH-seeking behavior and long-term potentiation. Rats were implanted with a cannula into lateral ventricle, then treated with saline or METH (5 mg/kg) during the acquisition phase of the conditioned place preference (CPP) test. On day 13 of the extinction phase, METH groups were divided into four groups: METH (0: saline, 1, or 2.5 (priming METH) mg/kg; i.p.) + vehicle (5 µl/rat) or a priming dose of METH (2.5 mg/kg; i.p.) + PNU (2 µg/5 µl; i.c.v.) and their preference scores were calculated on reinstatement day (day 14). Immediately following this, electrophysiology was performed to assay the field excitatory postsynaptic potential (fEPSP) slope and population spike (PS) amplitude between groups. The results showed that CPP induction by METH gradually declined to extinction on days 12 and 13. A priming METH treatment significantly increased preference for the METH-paired chamber when compared with other groups, but pre-treatment with PNU significantly attenuated this effect. PS amplitude and fEPSP slopes in vehicle + priming METH rats were greater when compared with other groups. Furthermore, PNU attenuated the priming METH-induced increase in PS amplitude. These findings suggest that PNU can decrease synaptic transmission and prevent METH reinstatement in rats.
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Affiliation(s)
- Siamak Shahidi
- Neurophysiology Research Center, Hamadan University of Medical Sciences, Hamadan, Iran
| | - Alireza Komaki
- Neurophysiology Research Center, Hamadan University of Medical Sciences, Hamadan, Iran
| | - Reihaneh Sadeghian
- Neurophysiology Research Center, Hamadan University of Medical Sciences, Hamadan, Iran.
| | - Sara Soleimani Asl
- Anatomy Departments, School of Medicine, Hamadan University of Medical Sciences, Hamadan, Iran
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Repeated 7-Day Treatment with the 5-HT 2C Agonist Lorcaserin or the 5-HT 2A Antagonist Pimavanserin Alone or in Combination Fails to Reduce Cocaine vs Food Choice in Male Rhesus Monkeys. Neuropsychopharmacology 2017; 42:1082-1092. [PMID: 27857126 PMCID: PMC5506793 DOI: 10.1038/npp.2016.259] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/28/2016] [Revised: 10/27/2016] [Accepted: 11/14/2016] [Indexed: 11/08/2022]
Abstract
Cocaine use disorder is a global public health problem for which there are no Food and Drug Administration-approved pharmacotherapies. Emerging preclinical evidence has implicated both serotonin (5-HT) 2C and 2A receptors as potential mechanisms for mediating serotonergic attenuation of cocaine abuse-related neurochemical and behavioral effects. Therefore, the present study aim was to determine whether repeated 7-day treatment with the 5-HT2C agonist lorcaserin (0.1-1.0 mg/kg per day, intramuscular; 0.032-0.1 mg/kg/h, intravenous) or the 5-HT2A inverse agonist/antagonist pimavanserin (0.32-10 mg/kg per day, intramuscular) attenuated cocaine reinforcement under a concurrent 'choice' schedule of cocaine and food availability in rhesus monkeys. During saline treatment, cocaine maintained a dose-dependent increase in cocaine vs food choice. Repeated pimavanserin (3.2 mg/kg per day) treatments significantly increased small unit cocaine dose choice. Larger lorcaserin (1.0 mg/kg per day and 0.1 mg/kg/h) and pimavanserin (10 mg/kg per day) doses primarily decreased rates of operant behavior. Coadministration of ineffective lorcaserin (0.1 mg/kg per day) and pimavanserin (0.32 mg/kg per day) doses also failed to significantly alter cocaine choice. These results suggest that neither 5-HT2C receptor activation nor 5-HT2A receptor blockade are sufficient to produce a therapeutic-like decrease in cocaine choice and a complementary increase in food choice. Overall, these results do not support the clinical utility of 5-HT2C agonists and 5-HT2A inverse agonists/antagonists alone or in combination as candidate anti-cocaine use disorder pharmacotherapies.
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Banks ML. Effects of 7-day repeated treatment with the 5-HT2A inverse agonist/antagonist pimavanserin on methamphetamine vs. food choice in male rhesus monkeys. Drug Alcohol Depend 2016; 165:260-4. [PMID: 27242287 PMCID: PMC4939103 DOI: 10.1016/j.drugalcdep.2016.05.014] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/16/2016] [Revised: 05/16/2016] [Accepted: 05/17/2016] [Indexed: 12/19/2022]
Abstract
BACKGROUND Preclinical drug vs. food choice is an emerging group of drug self-administration procedures that have shown predictive validity to clinical drug addiction. Emerging data suggest that serotonin (5-HT)2A receptors modulate mesolimbic dopamine function, such that 5-HT2A antagonists blunt the abuse-related neurochemical effects of monoamine transporter substrates, such as amphetamine or methamphetamine. Whether subchronic 5-HT2A antagonist treatment attenuates methamphetamine reinforcement in any preclinical drug self-administration procedure is unknown. The study aim was therefore to determine 7-day treatment effects with the 5-HT2A inverse agonist/antagonist pimavanserin on methamphetamine vs. food choice in monkeys. METHODS Behavior was maintained under a concurrent schedule of food delivery (1g pellets, fixed-ratio 100 schedule) and intravenous methamphetamine injections (0-0.32 mg/kg/injection, fixed-ratio 10 schedule) in male rhesus monkeys (n=3). Methamphetamine choice dose-effect functions were determined daily before and during 7-day repeated pimavanserin (1.0-10mg/kg/day, intramuscular) treatment periods. RESULTS Under control conditions, increasing methamphetamine doses resulted in a corresponding increase in methamphetamine vs. food choice. Repeated pimavanserin administration failed to attenuate methamphetamine choice and produce a reciprocal increase in food choice in any monkey up to doses (3.2-10mg/kg) that suppressed rates of operant responding primarily during components where behavior was maintained by food pellets. CONCLUSIONS Repeated 5-HT2A receptor inverse agonist/antagonist treatment did not attenuate methamphetamine reinforcement under a concurrent schedule of intravenous methamphetamine and food presentation in nonhuman primates. Overall, these results do not support the therapeutic potential of 5-HT2A inverse agonists/antagonists as candidate medications for methamphetamine addiction.
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Affiliation(s)
- Matthew L Banks
- Department of Pharmacology and Toxicology, Virginia Commonwealth University, Richmond, VA, USA; Institute for Drug and Alcohol Studies, Virginia Commonwealth University, Richmond, VA, USA.
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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: 209] [Impact Index Per Article: 20.9] [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.
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Predicting abuse potential of stimulants and other dopaminergic drugs: overview and recommendations. Neuropharmacology 2014; 87:66-80. [PMID: 24662599 DOI: 10.1016/j.neuropharm.2014.03.009] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2013] [Revised: 02/26/2014] [Accepted: 03/12/2014] [Indexed: 01/09/2023]
Abstract
Examination of a drug's abuse potential at multiple levels of analysis (molecular/cellular action, whole-organism behavior, epidemiological data) is an essential component to regulating controlled substances under the Controlled Substances Act (CSA). We reviewed studies that examined several central nervous system (CNS) stimulants, focusing on those with primarily dopaminergic actions, in drug self-administration, drug discrimination, and physical dependence. For drug self-administration and drug discrimination, we distinguished between experiments conducted with rats and nonhuman primates (NHP) to highlight the common and unique attributes of each model in the assessment of abuse potential. Our review of drug self-administration studies suggests that this procedure is important in predicting abuse potential of dopaminergic compounds, but there were many false positives. We recommended that tests to determine how reinforcing a drug is relative to a known drug of abuse may be more predictive of abuse potential than tests that yield a binary, yes-or-no classification. Several false positives also occurred with drug discrimination. With this procedure, we recommended that future research follow a standard decision-tree approach that may require examining the drug being tested for abuse potential as the training stimulus. This approach would also allow several known drugs of abuse to be tested for substitution, and this may reduce false positives. Finally, we reviewed evidence of physical dependence with stimulants and discussed the feasibility of modeling these phenomena in nonhuman animals in a rational and practical fashion. This article is part of the Special Issue entitled 'CNS Stimulants'.
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Graves SM, Napier TC. Mirtazapine alters cue-associated methamphetamine seeking in rats. Biol Psychiatry 2011; 69:275-81. [PMID: 21093851 PMCID: PMC3015001 DOI: 10.1016/j.biopsych.2010.09.032] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/04/2009] [Revised: 09/20/2010] [Accepted: 09/26/2010] [Indexed: 12/22/2022]
Abstract
BACKGROUND Methamphetamine (METH) is a potent psychostimulant, repeated use of which can result in a substance abuse disorder. Withdrawn individuals are highly prone to relapse, which may be driven, at least in part, by a hyperresponsivity to METH-associated cues that can prompt METH-seeking. Clinically efficacious pharmacotherapies for METH abuse are critically needed. Mirtazapine (Remeron) is an atypical antidepressant that antagonizes activated norepinephrine(α)₂, histamine₁ serotonin (5-HT)₂(A/C), and 5-HT₃ receptors. This pharmacologic profile prompted our interest in its potential for preventing relapse to METH-taking. This study tested the hypothesis that mirtazapine would attenuate METH-seeking in rats trained to self-administer METH. METHODS Rats were trained to self-administer METH in a lever-pressing operant task. The effect of mirtazapine on METH-seeking was determined by evaluating lever pressing in the presence of cues previously associated with METH, but in the absence of METH reinforcement. Two paradigms were used: cue reactivity, wherein rats do not undergo extinction training, and a cue-induced reinstatement paradigm after extinction. RESULTS Mirtazapine (5.0 mg/kg) pretreatment reduced METH-seeking by ∼ 50% in the first 15 min of cue reactivity and cue-induced reinstatement testing. This mirtazapine dose did not significantly affect motor performance. CONCLUSIONS This study revealed the overlapping nature of cue reactivity and cue-induced reinstatement procedures and provided preclinical evidence that mirtazapine can attenuate METH-seeking behavior.
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Affiliation(s)
- Steven M Graves
- Department of Pharmacology, Rush University Medical Center, Chicago, Illinois 60612, USA.
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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]
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Marona-Lewicka D, Chemel BR, Nichols DE. Dopamine D4 receptor involvement in the discriminative stimulus effects in rats of LSD, but not the phenethylamine hallucinogen DOI. Psychopharmacology (Berl) 2009; 203:265-77. [PMID: 18604600 DOI: 10.1007/s00213-008-1238-0] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/03/2008] [Accepted: 06/11/2008] [Indexed: 10/21/2022]
Abstract
RATIONALE Lysergic acid diethylamide (LSD) differs from other types of hallucinogens in that it possesses direct dopaminergic effects. The exact nature of this component has not been elucidated. OBJECTIVE The present study sought to characterize the effects of several dopamine D(4) agonists and antagonists on the discriminative stimulus effect of LSD at two pretreatment times and 2,5-dimethoxy-4-iodoamphetamine (DOI), a selective 5-HT(2A/2C) agonist. MATERIALS AND METHODS Male Sprague-Dawley rats were trained in a two-lever, fixed ratio (FR) 50, food-reinforced task with LSD-30 (0.08 mg/kg, i.p., 30-min pretreatment time), LSD-90 (0.16 mg/kg, i.p., 90-min pretreatment time), and DOI (0.4 mg/kg, i.p., 30-min pretreatment time) as discriminative stimuli. Substitution and combination tests with the dopamine D(4) agonists, ABT-724 and WAY 100635, were performed in all groups. Combination tests were run using the dopamine D(4) antagonists A-381393 and L-745,870 and two antipsychotic drugs, clozapine and olanzapine. RESULTS WAY 100635 produced full substitution in LSD-90 rats, partial substitution in LSD-30 rats, and saline appropriate responding in DOI-trained rats. ABT-724 partially mimicked the LSD-90 and LSD-30 cues, but produced no substitution in DOI-trained rats. In combination tests, both agonists shifted the dose-response curve of LSD leftward, most potently for the LSD-90 cue. The D(4) antagonists significantly attenuated both the LSD-90 and LSD-30 cue, but had no effect on the DOI cue. CONCLUSION Dopamine D(4) receptor activation plays a significant modulatory role in the discriminative stimulus effects in LSD-90-trained rats, most markedly for the later temporal phase of LSD, but has no effect on the cue produced by DOI.
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Affiliation(s)
- Danuta Marona-Lewicka
- Department of Medicinal Chemistry and Molecular Pharmacology, School of Pharmacy and Pharmaceutical Sciences-RHPH, Purdue University, 575 Stadium Mall Dr., West Lafayette, IN 47907-2091, USA
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Reduced sensitivity to the locomotor-stimulant effects of cocaine is associated with increased sensitivity to its discriminative stimulus properties. Behav Pharmacol 2009; 20:67-77. [PMID: 19125118 DOI: 10.1097/fbp.0b013e3283242fdd] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Outbred Long-Evans rats exhibit wide variation in their locomotor response to cocaine. Here, we investigated the relationship between these individual differences and interoceptive effects of cocaine in low cocaine responder (LCR) and high cocaine responder (HCR) phenotypes. Rats were trained to discriminate cocaine (10.0 mg/kg, intraperitoneally) from saline by repeated pairings of injections with one of two response levers. In subsequent tests for stimulus generalization to other cocaine doses (1.25-15.0 mg/kg), LCRs exhibited partial-to-full generalization at 1.85 and 2.5 mg/kg cocaine, respectively, whereas HCRs did not. When the selective 5-HT reuptake inhibitor fluoxetine (5.0 mg/kg) was coadministered with saline or different cocaine doses, we observed similar upward shifts in dose-response in both phenotypes. In contrast, coadministration of the 5-HT2A/2C agonist (+/-)-1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane (DOI; 0.3 mg/kg) led to partial substitution of DOI for cocaine and enhancement of the stimulus properties of 1.25 mg/kg cocaine in LCRs only. Finally, a retest of cocaine-induced locomotion after discrimination testing revealed marked behavioral sensitization in LCRs and modest changes in behavior in HCRs. Taken together, these results suggest that initial sensitivity to the locomotor-stimulant effects of cocaine is inversely related to its interoceptive properties and that differences in 5-HT systems may contribute to the phenotypic differences observed.
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Gatch MB, Flores E, Forster MJ. Nicotine and methamphetamine share discriminative stimulus effects. Drug Alcohol Depend 2008; 93:63-71. [PMID: 17961933 PMCID: PMC2377183 DOI: 10.1016/j.drugalcdep.2007.08.020] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/11/2007] [Revised: 08/20/2007] [Accepted: 08/21/2007] [Indexed: 11/26/2022]
Abstract
BACKGROUND Nicotine and methamphetamine are both abused in similar settings, sometimes together. Because there are known interactions between central nicotinic acetylcholine receptors and dopamine receptors, it is of interest to characterize the nature of the interaction of these two compounds in vivo. METHODS The purpose of this study was to characterize the extent to which these two compounds produce similar discriminative stimulus effects and to identify pharmacological mechanisms for their interaction. Male Sprague-Dawley rats were trained to discriminate methamphetamine or nicotine from saline. First, the ability of methamphetamine and nicotine to cross-substitute in rats trained to the other compound was tested. Subsequently, the ability of a dopamine antagonist (haloperidol) and a centrally acting nicotinic antagonist (mecamylamine) to block the discriminative stimulus effects of methamphetamine and nicotine were also tested. RESULTS Nicotine fully substituted in methamphetamine-trained rats, but methamphetamine only partially substituted in nicotine-trained rats. In nicotine-trained rats, mecamylamine fully antagonized the discriminative stimulus effects of nicotine, but haloperidol had no effect. The partial substitution of methamphetamine was partially attenuated by haloperidol, but not altered by mecamylamine. In methamphetamine-trained rats, mecamylamine failed to antagonize the discriminative stimulus effects of methamphetamine, but haloperidol fully blocked the methamphetamine cue. Mecamylamine blocked the ability of nicotine to substitute for methamphetamine, but haloperidol had no effect. CONCLUSIONS These results indicate that nicotine and methamphetamine share discriminative stimulus effects in some subjects and that the two compounds do not act at the same site, but produce their interaction indirectly. These findings suggest that these two compounds might be at least partially interchangeable in human users, and that there are potentially interesting pharmacological reasons for the commonly observed co-administration of nicotine and methamphetamine.
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Zaniewska M, McCreary AC, Przegaliński E, Filip M. Effects of the serotonin 5-HT2A and 5-HT2C receptor ligands on the discriminative stimulus effects of nicotine in rats. Eur J Pharmacol 2007; 571:156-65. [PMID: 17617403 DOI: 10.1016/j.ejphar.2007.05.067] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2007] [Revised: 05/25/2007] [Accepted: 05/30/2007] [Indexed: 11/29/2022]
Abstract
The present study tested the hypothesis that serotonergic (5-HT) 5-HT2A or 5-HT2C receptors or their pharmacological stimulation modulated the discriminative stimulus effects of nicotine in male Wistar rats. To this end the selective 5-HT2A receptor antagonist R-(+)-alpha-(2,3-dimethoxyphenyl)-1-[2-(4-fluorophenyl)ethyl]-4-piperidinemethanol (M100,907; 0.5-1 mg/kg, i.p.), the functional 5-HT2A receptor agonist 1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane hydrochloride (DOI; 0.1-1 mg/kg, s.c.), the selective 5-HT2C receptor antagonist 6-chloro-5-methyl-1-{[2-(2-methylpyrid-3-yloxy)pyrid-5-yl]carbamoyl}indoline (SB 242,084; 0.25-1 mg/kg, i.p.) and the 5-HT2C receptor agonists (S)-2-chloro-5-fluoro-indol-1-yl)-1-methylethylamine fumarate (Ro 60-0175; 0.3-1 mg/kg, s.c.) and (7bR, 10aR)-1,2,3,4,8,9,10,10a-octahydro-7bH-cyclopenta-[b][1,4]diazepino[6,7,1hi]indole (WAY 163,909; 0.75-1.5 mg/kg, i.p.) were used. Additionally, the effects of the selective alpha4beta2 nicotinic acetylcholine receptor subtype agonist 5-iodo-3-(2(S)-azetidinylmethoxy)pyridine (5-IA; 0.01 mg/kg, s.c.) were investigated. In rats trained to discriminate (-)-nicotine (0.4 mg/kg, s.c.) from saline in a two-lever, water-reinforced fixed ratio 10 task, substitutions were not observed with 5-HT2 receptor ligands (<32% nicotine-lever responding), conversely 5-IA induced a full substitution (100% nicotine-lever responding). In combination studies, fixed doses of M100,907 (0.5-1 mg/kg) or SB 242,084 (0.25-1 mg/kg) did not alter the dose-response curve of nicotine, while DOI (0.3 mg/kg), Ro 60-0175 (1 mg/kg) and WAY 163,909 (1 and 1.5 mg/kg) attenuated the discriminative stimulus effects of nicotine. The decrease in the expression of the discriminative stimulus effects of nicotine produced by DOI was blocked by M100,907 (1 mg/kg), but not by SB 242,084 (1 mg/kg), while that evoked by Ro 60-0175 or WAY 163,909 was blocked by SB 242,084 (1 mg/kg), but not by M100,907 (1 mg/kg). Further studies showed that DOI (0.3 mg/kg) and Ro 60-0175 (1 mg/kg), but not WAY 163,909 (1.5 mg/kg) blocked full substitution of 5-IA (0.01 mg/kg) for nicotine. Our pharmacological analyses indicate that tonic activation of 5-HT2A or 5-HT2C receptors is not required for subjective effects of nicotine, however these receptors appear to have inhibitory influence on nicotine cue, since pharmacological stimulation of either receptor attenuates the discriminative stimulus effects of nicotine.
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MESH Headings
- Aminopyridines/pharmacology
- Amphetamines/pharmacology
- Animals
- Azepines/pharmacology
- Azetidines/pharmacology
- Behavior, Animal/drug effects
- Brain/drug effects
- Brain/metabolism
- Discrimination, Psychological/drug effects
- Dose-Response Relationship, Drug
- Ethylamines/pharmacology
- Fluorobenzenes/pharmacology
- Indoles/pharmacology
- Ligands
- Male
- Nicotine/pharmacology
- Nicotinic Agonists/pharmacology
- Piperidines/pharmacology
- Pyridines/pharmacology
- Rats
- Rats, Wistar
- Receptor, Serotonin, 5-HT2A/metabolism
- Receptor, Serotonin, 5-HT2C/metabolism
- Receptors, Nicotinic/drug effects
- Receptors, Nicotinic/metabolism
- Serotonin 5-HT2 Receptor Agonists
- Serotonin Antagonists/pharmacology
- Serotonin Receptor Agonists/pharmacology
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Affiliation(s)
- Magdalena Zaniewska
- Laboratory of Drug Addiction Pharmacology, Department of Pharmacology, Institute of Pharmacology, Polish Academy of Sciences, 31-343 Kraków, 12 Smetna, Poland
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Liang JH, Wang K, Sun HL, Han R. Potentiating effect of tramadol on methamphetamine-induced behavioral sensitization in mice. Psychopharmacology (Berl) 2006; 185:1-10. [PMID: 16432683 DOI: 10.1007/s00213-005-0260-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/18/2004] [Accepted: 10/07/2005] [Indexed: 11/25/2022]
Abstract
RATIONALE Polydrug abuse is a common phenomenon in human drug addicts. Previous studies have shown that both tramadol (TRAM) and methamphetamine (METH) share the ability to modulate brain monoaminergic (dopamine, 5-hydroxytryptamine, and noradrenaline) systems that may be involved in behavioral sensitization to METH. Therefore, we hypothesized that there would be an interaction between TRAM and METH on behavioral sensitization induced by METH. OBJECTIVES To investigate whether TRAM affects METH-induced behavioral sensitization. METHODS Male Kunming mice were subjected to two regimens of drugs: (1) Mice were injected with TRAM (1-16 mg/kg, i.p.) alone or a combination of TRAM and METH (1 mg/kg, i.p.) once daily for 7 days. After 7 drug-free days (on day 15), animals were challenged with the corresponding TRAM dose or METH (1 mg/kg, i.p.). On days 1, 7, and 15, locomotion was monitored in the open field test after the last injection. (2) Mice received METH (1 mg/kg, i.p.) once daily for 7 days, followed by 7 drug-free days. On day 15, a challenge of TRAM (1-16 mg/kg, i.p.) or TRAM plus METH (1 mg/kg, i.p.) was given and then locomotor activity was quantified. RESULTS TRAM or METH challenge did not induce hyperlocomotion in mice chronically treated with TRAM, and TRAM challenge was insufficient to induce subsequent hyperlocomotion in METH-sensitized mice. However, TRAM significantly increased METH-induced hyperlocomotion. TRAM plus METH-sensitized mice showed a significantly greater hyperlocomotor response to METH challenge than METH-sensitized mice. Furthermore, TRAM (16 mg/kg, i.p.) plus METH (1 mg/kg, i.p.) challenge enhanced the sensitized locomotor response compared to METH-alone (1 mg/kg, i.p.) challenge in METH-sensitized mice. CONCLUSIONS TRAM fails to produce behavioral sensitization, and there is no apparent cross-sensitization between TRAM and METH. However, TRAM can increase METH-induced hyperlocomotion and potentiate the development and expression of behavioral sensitization to METH.
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Affiliation(s)
- Jian-Hui Liang
- Department of Neuropharmacology, National Institute on Drug Dependence, Peking University, 38 Xueyuan Road, Beijing 100083, People's Republic of China.
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17
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Müller CP, Huston JP. Determining the region-specific contributions of 5-HT receptors to the psychostimulant effects of cocaine. Trends Pharmacol Sci 2006; 27:105-12. [PMID: 16406129 DOI: 10.1016/j.tips.2005.12.003] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2005] [Revised: 11/09/2005] [Accepted: 12/08/2005] [Indexed: 11/30/2022]
Abstract
Cocaine is a drug of abuse that has complex neurochemical and behavioural profiles. When it became evident that models that involve only dopamine do not fully explain the complex effects of cocaine on behaviour, the focus of research expanded to include the 5-hydroxytryptamine (5-HT) system in the brain. The 5-HT system comprises several subtypes of 5-HT receptors, which contribute differentially to the various behavioural effects of cocaine. In this article, we describe which subtypes regulate behaviours that are related to cocaine addiction and how they might provide new therapeutic approaches. Numerous subpopulations of each 5-HT receptor can be distinguished according to their location in the brain. We also discuss how these subpopulations relate to the effects of 5-HT-receptor stimulation at the systemic level. These insights provide a new receptor-based approach for understanding the 5-HT mechanisms that subserve the actions of cocaine and possible pharmacotherapies against cocaine addiction.
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Affiliation(s)
- Christian P Müller
- Institute of Physiological Psychology I and Center for Biological and Medical Research, University of Düsseldorf, Universitätsstr. 1, 40225 Düsseldorf, Germany.
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18
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Filip M, Bubar MJ, Cunningham KA. Contribution of serotonin (5-HT) 5-HT2 receptor subtypes to the discriminative stimulus effects of cocaine in rats. Psychopharmacology (Berl) 2006; 183:482-9. [PMID: 16261316 DOI: 10.1007/s00213-005-0197-y] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/21/2005] [Accepted: 09/05/2005] [Indexed: 11/28/2022]
Abstract
RATIONALE The serotonin (5-hydroxytryptamine; 5-HT) 5-HT2 receptor (5-HT2R) family is an important regulator of the behavioral responsiveness to cocaine. OBJECTIVE The present study is an analysis of the role of the 5-HT2R subtypes (5-HT2AR, 5-HT2BR, and 5-HT2CR) in the discriminative stimulus effects of cocaine. METHODS Male Wistar rats were trained to discriminate cocaine (10 mg/kg) from saline in a two-lever, water-reinforced FR 20 task, and we investigated the ability of the 5-HT2AR antagonist 1(Z)-[2-(dimethylamino)ethoxyimino]-1(2-fluorophenyl)-3-(4-hydroxyphenyl)-2(E)-propene (SR 46349B), the 5-HT2BR antagonist N-(1-methyl-5-indolyl)-N'-(3-methyl-5-isothiazolyl) urea (SB 204741), and the 5-HT2CR antagonist [(+)-cis-4,5,7a,8,9,10,11,11a-octahydro-7H-10-methylindolo(1,7-bC)(2,6)naphthyridine (SDZ SER-082) to substitute for or to modulate the stimulus effects of cocaine. RESULTS Pretreatment with SR 46349B (0.5-1 mg/kg) resulted in a rightward shift of the cocaine dose-response curve, while SDZ SER-082 (1 mg/kg) shifted the dose-response for cocaine to the left; SB 204741 (1-3 mg/kg) was inactive. CONCLUSIONS Our pharmacological analyses of selective antagonists of 5-HT2AR, 5-HT2BR, and 5-HT2CR indicate oppositional influence of 5-HT2AR and 5-HT2CR on the stimulus effects of cocaine and exclude a role for the 5-HT2BR. These data suggest that 5-HT2AR and 5-HT2CR may be important in modulating the subjective effects of cocaine in humans.
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MESH Headings
- Animals
- Cocaine/pharmacology
- Conditioning, Operant/drug effects
- Discrimination, Psychological/drug effects
- Dose-Response Relationship, Drug
- Fluorobenzenes/pharmacology
- Indoles/pharmacology
- Male
- Naphthyridines/pharmacology
- Phenols/pharmacology
- Rats
- Rats, Wistar
- Receptor, Serotonin, 5-HT2A/drug effects
- Receptor, Serotonin, 5-HT2B/drug effects
- Receptor, Serotonin, 5-HT2C/drug effects
- Receptors, Serotonin/drug effects
- Reinforcement Schedule
- Serotonin Antagonists/pharmacology
- Serotonin Receptor Agonists/pharmacology
- Stimulation, Chemical
- Urea/analogs & derivatives
- Urea/pharmacology
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Affiliation(s)
- Malgorzata Filip
- Institute of Pharmacology, Polish Academy of Sciences, 31-343, Cracow, Poland
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Gatch MB, Selvig M, Forster MJ. GABAergic modulation of the discriminative stimulus effects of methamphetamine. Behav Pharmacol 2005; 16:261-6. [PMID: 15961966 PMCID: PMC3878065 DOI: 10.1097/01.fbp.0000166464.68186.25] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
To assess whether gamma-aminobutyric acid (GABA) modulation of dopamine is important in mediation of the discriminative stimulus effects of methamphetamine, the GABA compounds chlordiazepoxide (benzodiazepine site agonist), pentobarbital (barbiturate site agonist), bicuculline and pentylenetetrazol (GABA(A) receptor antagonists) were tested in Sprague-Dawley rats trained to discriminate methamphetamine (1 mg/kg, i.p.) from saline. Each of the compounds produced modest amounts of methamphetamine-appropriate responding (20-35%) when tested alone. When tested in combination with methamphetamine, the antagonists (bicuculline and pentylenetetrazol) failed to shift the methamphetamine dose-effect curve. In contrast, chlordiazepoxide (25 mg/kg, i.p.) reduced methamphetamine-appropriate responding at each dose of methamphetamine tested, and pentobarbital (10 mg/kg, i.p.) dose-dependently decreased the discriminative stimulus effects of 1 mg/kg methamphetamine. In conclusion, GABA(A) antagonists and positive modulators likely do not produce methamphetamine-like stimulus effects. However, activation of GABA(A) receptors can interfere with the discriminative stimulus effects of methamphetamine.
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Affiliation(s)
- M B Gatch
- Department of Pharmacology and Neuroscience, University of North Texas Health Science Center, Fort Worth, 76107, USA.
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20
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Batman AM, Munzar P, Beardsley PM. Attenuation of nicotine's discriminative stimulus effects in rats and its locomotor activity effects in mice by serotonergic 5-HT2A/2C receptor agonists. Psychopharmacology (Berl) 2005; 179:393-401. [PMID: 15565434 DOI: 10.1007/s00213-004-2035-z] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/08/2004] [Accepted: 09/10/2004] [Indexed: 10/26/2022]
Abstract
RATIONALE Reports have indicated that administration of nicotine inhibits, while withdrawal of chronically administered nicotine augments effects of serotonergic 5HT2A/2C agonists. OBJECTIVE It was our objective to determine whether 5HT2A/2C agonists can modulate the discriminative stimulus effects of nicotine in rats or its locomotor activity effects in mice. METHODS Adult male Sprague-Dawley rats were trained to discriminate 0.3 mg/kg nicotine base from saline in a two-lever, fixed-ratio (FR10), food-reinforced, operant-conditioning task during daily (Monday-Friday) 15-min experimental sessions. After characterizing a dose-response curve for nicotine, we tested the ability of the 5HT(2A/2C) agonists (+/-)-1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane HCL (DOI; 0.18-1.0 mg/kg) and 1-(4-bromo-2, 5-dimethoxyphenyl)-2-aminopropane (DOB; 0.1-1.0 mg/kg), the 5HT2C agonist 6-chloro-2-(1-piperazinyl)pyrazine hydrochloride (MK 212; 0.1 mg/kg-1.0 mg/kg), and the 5HT1A agonist (+/-)-8-hydroxy-2-(di-n-propylamino)tetralin hydrobromide (8-OH-DPAT; 0.01 mg/kg-1.0 mg/kg) to modulate nicotine's discriminative stimulus effects. After finding that DOI was able to attenuate the percentage nicotine lever responding (%NLR), we tested for it to also reverse nicotine's effects on locomotor activity in mice. RESULTS The 5HT2A/2C agonists-in particular DOI-dose dependently attenuated %NLR. The effects of DOI were reversed by the 5HT2A/2C antagonist ketanserin. MK 212 and 8-OH-DPAT had irregular effects among rats and only reduced %NLR to below 50% levels at doses markedly suppressing responding. DOI also dose dependently blocked nicotine's acute rate-lowering locomotor activity effects. CONCLUSIONS These results indicate that activation of serotonin 5HT2A/2C receptors can blunt the discriminative stimulus and locomotor activity effects of nicotine and presents the possibility that activation of these receptors might also be able to attenuate other effects of nicotine.
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Affiliation(s)
- Angela M Batman
- Department of Pharmacology and Toxicology, VCU Medical Center, Virginia Commonwealth University, P.O. Box 980613, 410 North 12th Street, Smith Bld. #756, Richmond, VA 23298-0613, USA
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Burmeister JJ, Lungren EM, Kirschner KF, Neisewander JL. Differential roles of 5-HT receptor subtypes in cue and cocaine reinstatement of cocaine-seeking behavior in rats. Neuropsychopharmacology 2004; 29:660-8. [PMID: 14627998 DOI: 10.1038/sj.npp.1300346] [Citation(s) in RCA: 92] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The 5-HT indirect agonist, d-fenfluramine, attenuates cue reinstatement of extinguished cocaine-seeking behavior. To investigate the role of 5-HT receptor subtypes in this effect, we examined whether the attenuation is reversed by either a 5-HT(1A), 5-HT(2A/C), or 5-HT(2C) receptor antagonist. We also examined the effects of the antagonists alone on both cue and cocaine-primed reinstatement. Rats that had been trained to press a lever for cocaine (0.75 mg/kg/0.1 ml, i.v.) paired with light and tone cues underwent daily extinction sessions during which responding had no consequences. We then examined the effects of WAY 100635 (0-1.0 mg/kg, s.c.), ketanserin (0-10.0 mg/kg, i.p.), or SB 242,084 (0-1.0 mg/kg, i.p.) with and without d-fenfluramine (1.0 mg/kg, i.p.) pretreatment on cue reinstatement. Subsequently, we examined the effects of the antagonists on cocaine-primed (7.5 or 15.0 mg/kg, i.p.) reinstatement. The 5-HT(1A) antagonist, WAY 100635, failed to alter cue reinstatement, but attenuated cocaine reinstatement. Conversely, the 5-HT(2A/C) antagonist, ketanserin, attenuated cue reinstatement, but failed to alter cocaine reinstatement. The 5-HT(2C)-selective antagonist, SB 242,084, did not alter cue or cocaine reinstatement, but was the only drug that reversed the d-fenfluramine-induced attenuation of cue reinstatement. The findings suggest that stimulation of 5-HT(1A) receptors plays a critical role in cocaine-primed, but not cue, reinstatement. Furthermore, 5-HT(2A) and 5-HT(2C) receptors may play oppositional roles in cue reinstatement. The SB 242,084 reversal of the d-fenfluramine attenuation suggests that stimulation of 5-HT(2C) receptors inhibits cue reinstatement, whereas the ketanserin-induced attenuation of cue reinstatement suggests that decreased stimulation of 5-HT(2A) receptors inhibits this behavior.
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Justinova Z, Ferre S, Segal PN, Antoniou K, Solinas M, Pappas LA, Highkin JL, Hockemeyer J, Munzar P, Goldberg SR. Involvement of adenosine A1 and A2A receptors in the adenosinergic modulation of the discriminative-stimulus effects of cocaine and methamphetamine in rats. J Pharmacol Exp Ther 2003; 307:977-86. [PMID: 14557381 DOI: 10.1124/jpet.103.056762] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Adenosine, by acting on adenosine A1 and A2A receptors, is known to antagonistically modulate dopaminergic neurotransmission. We have recently reported that nonselective adenosine receptor antagonists (caffeine and 3,7-dimethyl-1-propargylxanthine) can partially substitute for the discriminative-stimulus effects of methamphetamine. In the present study, by using more selective compounds, we investigated the involvement of A1 and A2A receptors in the adenosinergic modulation of the discriminative-stimulus effects of both cocaine and methamphetamine. The effects of the A1 receptor agonist N6-cyclopentyladenosine (CPA; 0.01-0.1 mg/kg) and antagonist 8-cyclopentyl-1,3-dimethylxanthine (CPT; 1.3-23.7 mg/kg) and the A2A receptor agonist 2-p-(2-carboxyethyl)phenethylamino-5'-N-ethylcarboxamidoadenosine hydrochloride (CGS 21680; 0.03-0.18 mg/kg) and antagonist 3-(3-hydroxypropyl)-8-(3-methoxystyryl)-7-methyl-1-propargylxanthin phosphate disodium salt (MSX-3; 1-56 mg/kg) were evaluated in rats trained to discriminate either 1 mg/kg methamphetamine or 10 mg/kg cocaine from saline under a fixed-ratio 10 schedule of food presentation. The A1 and A2A receptor antagonists (CPT and MSX-3) both produced high levels of drug-lever selection when substituted for either methamphetamine or cocaine and significantly shifted dose-response curves of both psychostimulants to the left. Unexpectedly, the A2A receptor agonist CGS 21680 also produced drug-appropriate responding (although at lower levels) when substituted for the cocaine-training stimulus, and both CGS 21680 and the A1 receptor agonist CPA significantly shifted the cocaine dose-response curve to the left. In contrast, both agonists did not produce significant levels of drug-lever selection when substituted for the methamphetamine-training stimulus and failed to shift the methamphetamine dose-response curve. Therefore, adenosine A1 and A2A receptors appear to play important but differential roles in the modulation of the discriminative-stimulus effects of methamphetamine and cocaine.
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Affiliation(s)
- Zuzana Justinova
- Preclinical Pharmacology Section, NIDA, NIH, 5500 Nathan Shock Drive, Baltimore, MD 21224, USA
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Millan MJ, Veiga S, Girardon S, Brocco M. Blockade of serotonin 5-HT1B and 5-HT2A receptors suppresses the induction of locomotor activity by 5-HT reuptake inhibitors, citalopram and fluvoxamine, in NMRI mice exposed to a novel environment: a comparison to other 5-HT receptor subtypes. Psychopharmacology (Berl) 2003; 168:397-409. [PMID: 12721776 DOI: 10.1007/s00213-003-1389-y] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/06/2002] [Accepted: 12/14/2002] [Indexed: 01/07/2023]
Abstract
RATIONALE Though 5-HT plays an important role in the modulation of motor function, which is perturbed in depressive states, little is known concerning the influence of serotonin reuptake inhibitors (SSRIs) on locomotor activity (LA). Recently, we demonstrated that SSRIs, such as citalopram, enhance LA in mice exposed to a novel environment. OBJECTIVES This study examined the role of multiple classes of 5-HT receptor in citalopram-induced LA. METHODS The most selective antagonists currently available were used. RESULTS Citalopram-induced LA was dose-dependently attenuated by the 5-HT1B/1D receptor antagonists, S18127, GR125,743 and GR127,935, and by the selective 5-HT1B antagonist, SB224,289, but unaffected by the selective 5-HT1A antagonist, WAY100,635. The selective antagonists at 5-HT2A receptors, MDL100,907 and SR46,349 also dose-dependently attenuated induction of locomotion by citalopram, whereas the 5-HT2B antagonist, SB204,741, and the 5-HT2B/2C antagonist, SB206,553 were ineffective. Further, the selective 5-HT2C antagonist, SB242,084, potentiated the response to citalopram. Selective antagonists at 5-HT3 (ondansetron), 5-HT4 (GR125,487), 5-HT6 (SB271,046) and 5-HT7 (SB269,970) receptors did not significantly modify the action of citalopram. Underpinning these findings, SB224,289, GR125,743, MDL100,907 and SR46,349 likewise attenuated induction of locomotion by a further SSRI, fluvoxamine. CONCLUSIONS The locomotor response to SSRIs of mice exposed to a novel environment is mediated via 5-HT1B and 5-HT2A receptors. In view of the importance of motor function to the etiology and treatment of depression, the significance of these observations to the clinical actions of SSRIs will be of interest to elucidate.
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MESH Headings
- Animals
- Citalopram/pharmacology
- Environment Design
- Fluvoxamine/pharmacology
- Injections, Subcutaneous
- Male
- Mice
- Motor Activity/drug effects
- Movement Disorders/prevention & control
- Receptor, Serotonin, 5-HT1B/drug effects
- Receptor, Serotonin, 5-HT1B/physiology
- Receptor, Serotonin, 5-HT2B/drug effects
- Receptor, Serotonin, 5-HT2B/physiology
- Receptors, Serotonin/classification
- Serotonin 5-HT1 Receptor Antagonists
- Serotonin 5-HT2 Receptor Antagonists
- Selective Serotonin Reuptake Inhibitors/pharmacology
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Affiliation(s)
- Mark J Millan
- Psychopharmacology Department, Institut de Recherches Servier, Centre de Recherches de Croissy, 125 Chemin de Ronde, 78290 Croissy/Seine, France.
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