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Gutierrez A, Nguyen JD, Creehan KM, Grant Y, Taffe MA. Adult Consequences of Repeated Nicotine Vapor Inhalation in Adolescent Rats. Nicotine Tob Res 2024; 26:715-723. [PMID: 37946372 PMCID: PMC11109496 DOI: 10.1093/ntr/ntad211] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2023] [Revised: 10/03/2023] [Accepted: 10/20/2023] [Indexed: 11/12/2023]
Abstract
INTRODUCTION There has been a resurgence in nicotine inhalation in adolescents due to the popularity and availability of Electronic Nicotine Delivery Systems (ENDS). Almost five times as many US high-school seniors inhale nicotine vapor daily compared with those who smoke tobacco. This study was conducted to determine the impact of repeated adolescent vapor inhalation of nicotine on behavior in adulthood. METHODS Male and female Sprague-Dawley rats were exposed to 30-minute sessions of ENDS vapor inhalation, twice daily, from post-natal day (PND) 31-40. Conditions included vapor from the propylene glycol (PG) vehicle or nicotine (30 mg/mL in the PG). Animals were assessed for effects of nicotine on open field (PND 74-105) and wheel activity (PND 126-180) and for volitional exposure to nicotine vapor (PND 285-395). Plasma nicotine and cotinine were assessed in separate groups of male and female Wistar and Sprague-Dawley rats after a single nicotine inhalation session. RESULTS Group mean plasma nicotine ranged from 39 to 59 ng/mL post-session with minimal strain differences detected. Adolescent nicotine exposure enhanced sensitivity to the locomotor stimulating effects of nicotine (0.1-0.8 mg/kg, s.c.) in an open field in female rats, but didn't change the effects of nicotine on wheel activity. Female rats exposed to nicotine (30 mg/mL) vapor as adolescents responded more vigorously than PG-exposed females to nicotine vapor in a fixed ratio 5 challenge. CONCLUSIONS Repeated adolescent nicotine vapor inhalation leads to enhanced liability for volitional exposure to nicotine vapor in adulthood in female rats, but minimal change in spontaneous locomotor behavior. IMPLICATIONS These results show that adolescent vaping of nicotine can lead to lasting sensitization to the effects of nicotine in adulthood, including volitional responding for nicotine vapor. Demonstration of this in a controlled animal model establishes causality in a manner not possible from longitudinal evidence in human populations. These findings further highlight the importance of decreasing adolescent nicotine exposure to e-cigarettes to reduce consumption in adulthood.
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Affiliation(s)
- Arnold Gutierrez
- Department of Neuroscience; The Scripps Research Institute; La Jolla, CA, USA
- Department of Psychiatry, University of California, San Diego; La Jolla, CA, USA
| | - Jacques D Nguyen
- Department of Neuroscience; The Scripps Research Institute;La Jolla, CA, USA
- Department of Psychiatry, University of California, San Diego; La Jolla, CA, USA
- Department of Psychology and Neuroscience, Baylor University;Waco, TX, USA
| | - Kevin M Creehan
- Department of Neuroscience; The Scripps Research Institute;La Jolla, CA, USA
- Department of Psychiatry, University of California, San Diego; La Jolla, CA, USA
| | - Yanabel Grant
- Department of Neuroscience; The Scripps Research Institute;La Jolla, CA, USA
- Department of Psychiatry, University of California, San Diego; La Jolla, CA, USA
| | - Michael A Taffe
- Department of Neuroscience; The Scripps Research Institute; La Jolla, CA, USA
- Department of Psychiatry, University of California, San Diego; La Jolla, CA, USA
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Gutierrez A, Creehan KM, Grant Y, Taffe MA. Adult consequences of repeated nicotine and Δ 9-tetrahydrocannabinol (THC) vapor inhalation in adolescent rats. Psychopharmacology (Berl) 2024; 241:585-599. [PMID: 38282127 PMCID: PMC10884208 DOI: 10.1007/s00213-024-06545-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/11/2023] [Accepted: 01/20/2024] [Indexed: 01/30/2024]
Abstract
RATIONALE Use of electronic drug delivery systems (EDDS, "e-cigarettes") to ingest nicotine and Δ9-tetrahydrocannabinol (THC) has surged in adolescents in the USA; five times as many high-school seniors vape nicotine daily using tobacco. At the same time, 19.5% of seniors use cannabis at least monthly, with 12% using EDDS to deliver it. OBJECTIVES This study was conducted to examine the impact of repeated adolescent vapor inhalation of nicotine and THC in rats. METHODS Female Sprague-Dawley rats were exposed to 30-min sessions of vapor inhalation, twice daily, from post-natal day (PND) 31 to PND 40. Conditions included vapor from the propylene glycol (PG) vehicle, nicotine (60 mg/mL in the PG), THC (100 mg/mL in the PG), or the combination of nicotine (60 mg/mL) and THC (100 mg/mL). Rats were assessed on wheel activity, heroin anti-nociception and nicotine and heroin vapor volitional exposure during adulthood. RESULTS Nicotine-exposed rats exhibited few differences as adults, but were less sensitive to anti-nociceptive effects of heroin (1 mg/kg, s.c.). THC- and THC + nicotine-exposed rats were less spontaneously active, and obtained fewer nicotine vapor deliveries as adults. In contrast, THC-exposed rats obtained volitional heroin vapor at rates indistinguishable from the non-THC-exposed groups. Repeated THC exposure also caused tolerance to temperature-disrupting effects of THC (5 mg/kg, i.p.). CONCLUSIONS These studies further confirm that the effects of repeated vapor exposure to THC in adolescence last into early to middle adulthood, including decreased volitional consumption of nicotine. Effects of repeated nicotine in adolescence were comparatively minor.
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Affiliation(s)
- Arnold Gutierrez
- Department of Psychiatry, University of California, 9500 Gilman Drive, San Diego, La Jolla, CA, 92093, USA
| | - Kevin M Creehan
- Department of Psychiatry, University of California, 9500 Gilman Drive, San Diego, La Jolla, CA, 92093, USA
| | - Yanabel Grant
- Department of Psychiatry, University of California, 9500 Gilman Drive, San Diego, La Jolla, CA, 92093, USA
| | - Michael A Taffe
- Department of Psychiatry, University of California, 9500 Gilman Drive, San Diego, La Jolla, CA, 92093, USA.
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Gutierrez A, Taffe MA. Rats chasing the dragon: A new heroin inhalation method. J Neurosci Methods 2024; 402:110013. [PMID: 37989452 DOI: 10.1016/j.jneumeth.2023.110013] [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: 08/10/2023] [Revised: 11/09/2023] [Accepted: 11/16/2023] [Indexed: 11/23/2023]
Abstract
BACKGROUND Despite extensive human use of inhalation for ingesting opioids, models in rodents have mostly been limited to parenteral injection and oral dosing. Methods using electronic drug delivery systems (EDDS; "e-cigarettes") have shown efficacy in rodent models but these do not faithfully mimic the most popular human inhalation method of heating heroin to the point of vaporization. NEW METHOD Middle aged rats were exposed to vapor created by direct heating of heroin HCl powder in a ceramic e-cigarette type atomizer. Efficacy was determined with a warm water tail withdrawal nociception assay, rectal temperature and self-administration. RESULTS Ten minutes of inhalation of vaporized heroin slowed response latency in a warm water tail withdrawal assay and increased rectal temperature in male rats, in a dose-dependent manner. Similar antinociceptive effects in female rats were attenuated by the opioid antagonist naloxone (1.0 mg/kg, s.c.). Female rats made operant responses for heroin vapor in 15-minute sessions, increased their response rate when the reinforcement ratio increased from FR1 to FR5, and further increased their responding when vapor delivery was omitted. Anti-nociceptive effects of self-administered volatilized heroin were of a similar magnitude as those produced by the 10-minute non-contingent exposure. COMPARISON WITH EXISTING METHODS Inhalation of directly volatilized heroin successfully produces heroin-typical effects, comparable to EDDS inhalation delivery. CONCLUSIONS This study shows that "chasing the dragon" methods of inhalation of heroin can be modeled successfully in the rat. Inhalation techniques may be particularly useful for longer term studies deep into the middle age of rats.
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Affiliation(s)
- Arnold Gutierrez
- Department of Psychiatry, University of California, San Diego, CA, USA
| | - Michael A Taffe
- Department of Psychiatry, University of California, San Diego, CA, USA.
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Gutierrez A, Creehan KM, Grant Y, Taffe MA. Adult consequences of repeated nicotine and Δ 9 -tetrahydrocannabinol (THC) vapor inhalation in adolescent rats. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.09.08.556932. [PMID: 37745433 PMCID: PMC10515744 DOI: 10.1101/2023.09.08.556932] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/26/2023]
Abstract
The use of Electronic Drug Delivery Systems (EDDS, "e-cigarettes") to ingest nicotine and Δ 9 -tetrahydrocannabinol (THC) has surged in adolescent populations in the United States, as five times as many high-school seniors vape nicotine daily as use tobacco. At the same time 19.5% of seniors use cannabis at least monthly, with 12% using EDDS to deliver it. This study was conducted to examine the impact of repeated adolescent vapor inhalation of nicotine and THC in rats. Female Sprague-Dawley rats were exposed to 30-minute sessions of vapor inhalation, twice daily, from Post-Natal Day (PND) 31 to PND 40. Conditions included vapor from the propylene glycol (PG) vehicle, Nicotine (60 mg/mL in the PG), THC (100 mg/mL in the PG) or the combination of Nicotine (60 mg/mL) and THC (100 mg/mL). Rats were assessed on wheel activity, heroin anti-nociception and nicotine and heroin vapor volitional exposure during adulthood. Nicotine exposed rats exhibited few differences as adults, but were less sensitive to anti-nociceptive effects of heroin (1 mg/kg, s.c.). THC- and THC+Nicotine-exposed rats were less spontaneously active, and obtained fewer nicotine vapor deliveries as adults. In contrast, THC exposed rats obtained volitional heroin vapor at rates indistinguishable from the non-THC-exposed groups. Repeated THC exposure also caused tolerance to temperature-disrupting effects of THC (5 mg/kg, i.p.). These studies further confirm that the effects of repeated vapor exposure to THC in adolescence last into early to middle adulthood, including decreased volitional consumption of nicotine. Effects of repeated nicotine in adolescence were comparatively minor.
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Gutierrez A, Taffe MA. Rats Chasing the Dragon: A new heroin inhalation method. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.08.09.552712. [PMID: 37786688 PMCID: PMC10541576 DOI: 10.1101/2023.08.09.552712] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/04/2023]
Abstract
Rationale Despite extensive human use of the inhalation route for ingesting opioids, models in rodents have mostly been limited to parenteral injection and oral dosing. Methods using electronic drug delivery systems (EDDS; "e-cigarettes") have shown efficacy in rodent models but these do not faithfully mimic the most popular human inhalation method of heating heroin to the point of vaporization. Objective This study was designed to determine if direct volatilization of heroin hydrochloride delivers effective heroin doses to rodents. Methods Middle aged rats were exposed to vapor created by direct heating of heroin HCl powder in a ceramic e-cigarette type atomizer. Efficacy was determined with a warm water tail withdrawal nociception assay, rectal temperature and self-administration. Results Ten minutes of inhalation of vaporized heroin slowed response latency in a warm water tail withdrawal assay and increased rectal temperature in male rats, in a dose-dependent manner. Similar antinociceptive effects in female rats were attenuated by the opioid antagonist naloxone (1.0 mg/kg, s.c.). Female rats made operant responses for heroin vapor in 15-minute sessions, increased their response rate when the reinforcement ratio increased from FR1 to FR5, and further increased their responding when vapor delivery was omitted. Anti-nociceptive effects of self-administered volatilized heroin were of a similar magnitude as those produced by the 10-minute non-contingent exposure. Conclusions This study shows that "chasing the dragon" methods of inhalation of heroin can be modeled successfully in the rat. Inhalation techniques may be particularly useful for longer term studies deep into middle age of rat species.
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Taffe MA, Nguyen JD, Vandewater SA, Grant Y, Dickerson TJ. Effects of α-pyrrolidino-phenone cathinone stimulants on locomotor behavior in female rats. Drug Alcohol Depend 2021; 227:108910. [PMID: 34332176 PMCID: PMC9812683 DOI: 10.1016/j.drugalcdep.2021.108910] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Revised: 06/05/2021] [Accepted: 06/08/2021] [Indexed: 01/07/2023]
Abstract
The α-pyrrolidino-phenone cathinone stimulants first came to widespread attention because of bizarre behavior consequent to the use of α-pyrrolidinopentiophenone (α-PVP, "flakka") reported in popular press. As with other designer drugs, diversification of cathinones has been driven by desirable subjective effects, but also by attempts to stay ahead of legal controls of specific molecules. The α-pyrrolidinohexiophenone (α-PHP) and α-pyrrolidinopropiophenone (α-PPP) compounds have been relatively under-investigated relative to α-PVP and provide a key opportunity to also investigate structure-activity relationships, i.e., how the extension of the alpha carbon chain may affect potency or efficacy. Female rats were used to contrast the effects of α-PHP and α-PPP with those of α-PVP in altering wheel activity and effects on spontaneous locomotion, temperature and intracranial self-stimulation reward. The α-PPP, α-PHP and α-PVP compounds (5, 10 mg/kg, i.p.) suppressed wheel activity. Inhalation of α-PHP or α-PVP also suppressed wheel activity, but for an abbreviated duration compared with the injection route. Spontaneous activity was increased, and brain reward thresholds decreased, in a dose-dependent manner by all three compounds; only small decrements in body temperature were observed. These data show that all three of the α-pyrrolidino-phenone cathinones exhibit significant stimulant-like activity in female rats. Differences were minor and abuse liability is therefore likely to be equivalent for all three α-pyrrolidino-phenones.
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Affiliation(s)
- Michael A Taffe
- Department of Neuroscience, The Scripps Research Institute, La Jolla, CA, USA; Department of Psychiatry, University of California San Diego, La Jolla, CA, USA.
| | - Jacques D Nguyen
- Department of Neuroscience, The Scripps Research Institute, La Jolla, CA, USA; Department of Psychiatry, University of California San Diego, La Jolla, CA, USA
| | - Sophia A Vandewater
- Department of Neuroscience, The Scripps Research Institute, La Jolla, CA, USA
| | - Yanabel Grant
- Department of Neuroscience, The Scripps Research Institute, La Jolla, CA, USA; Department of Psychiatry, University of California San Diego, La Jolla, CA, USA
| | - Tobin J Dickerson
- Department of Chemistry, The Scripps Research Institute, La Jolla, CA, USA
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Mead J, Parrott A. Mephedrone and MDMA: A comparative review. Brain Res 2020; 1735:146740. [PMID: 32087112 DOI: 10.1016/j.brainres.2020.146740] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2019] [Revised: 02/13/2020] [Accepted: 02/18/2020] [Indexed: 01/10/2023]
Abstract
Mephedrone and MDMA are both constituents of party drugs, with mephedrone being relatively new compared to MDMA. This review compares current knowledge regarding the patterns of usage and neuropsychobiological effects of both mephedrone and MDMA. Both drugs share common psychoactive effects, the duration of which is significantly shorter with mephedrone use, attributing towards a pattern of binge use among users. Both drugs have also been associated with adverse health, psychiatric, and neurocognitive problems. Whilst there is extensive research into the psychobiological problems induced by MDMA, the evidence for mephedrone is comparatively limited. The adverse effect profile of mephedrone appears to be less severe than that of MDMA. Users often believe it to be safer, although both drugs have been associated with overdoses. The neurotoxic potential of mephedrone appears to be low, whereas MDMA can cause long-term damage to the serotonergic system, although this needs further investigation. The abuse liability of mephedrone is significantly greater than that of MDMA, raising concerns regarding the impact of lifetime usage on users. Given that mephedrone is relatively new, the effects of long-term exposure are yet to be documented. Future research focused on lifetime users may highlight more severe neuropsychobiological effects from the drug.
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Affiliation(s)
- Jessica Mead
- Department of Psychology, School of Human and Health Sciences, Swansea University, Swansea, Wales, United Kingdom.
| | - Andrew Parrott
- Department of Psychology, School of Human and Health Sciences, Swansea University, Swansea, Wales, United Kingdom
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Tolerance to hypothermic and antinoceptive effects of ∆9-tetrahydrocannabinol (THC) vapor inhalation in rats. Pharmacol Biochem Behav 2018; 172:33-38. [PMID: 30031028 DOI: 10.1016/j.pbb.2018.07.007] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/29/2018] [Revised: 06/29/2018] [Accepted: 07/18/2018] [Indexed: 01/15/2023]
Abstract
RATIONALE A reduced effect of a given dose of ∆9-tetrahydrocannabinol (THC) emerges with repeated exposure to the drug. This tolerance can vary depending on THC dose, exposure chronicity and the behavioral or physiological measure of interest. A novel THC inhalation system based on e-cigarette technology has been recently shown to produce the hypothermic and antinociceptive effects of THC in rats. OBJECTIVE To determine if tolerance to these effects can be produced with repeated vapor inhalation. METHODS Groups of male and female Wistar rats were exposed to 30 min of inhalation of the propylene glycol (PG) vehicle or THC (200 mg/mL in PG) two or three times per day for four days. Rectal temperature changes and nociception were assessed after the first exposure on the first and fourth days of repeated inhalation. RESULTS Female, but not male, rats developed tolerance to the hypothermic and antinociceptive effects of THC after four days of twice-daily THC vapor inhalation. Thrice daily inhalation for four days resulted in tolerance in both male and female rats. The plasma THC levels reached after a 30 min inhalation session did not differ between the male and female rats. CONCLUSIONS Repeated daily THC inhalation induces tolerance in female and male rats, providing further validation of the vapor inhalation method for preclinical studies.
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Tao R, Shokry IM, Callanan JJ. Environment Influencing Serotonin Syndrome Induced by Ecstasy Abuse. ANNALS OF FORENSIC RESEARCH AND ANALYSIS 2017; 4:1039. [PMID: 29732414 PMCID: PMC5931730] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Ecstasy is a recreational drug containing 3,4-methylenedioxymethamphetamine (MDMA). In the U.S., there are several millions of lifetime users, and millions each year added to the list as new users. Only several thousand every year show signs of severe toxicity and require emergency intervention. The illness is known as serotonin (5-HT) syndrome, which can be mild, moderate or severe. The relationship between mild, moderate and severe syndromes appears to be interchangeable, but the severe syndrome is life-threatening. The serotonergic mechanisms of how the mild or moderate syndrome becomes severe and life-threatening have attracted considerable attention in the last few years as an effort to explore new treatments potentially to manage illness and prevent death of patients. High levels of extracellular 5-HT in the brain produced by large doses of MDMA are not always necessary to cause a severe serotonin syndrome. Additional mechanisms may be more important. Recent research has demonstrated that environmental conditions (i.e., non-drug factors) are more critical in determining the severity of MDMA-induced serotonin syndrome than the drug dose. The purpose of the current article was to review available evidence regarding the effect of non-drug factors on serotonergic extrasynaptic receptor responsivity and the severity of MDMA-induced serotonin syndrome.
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Affiliation(s)
- Rui Tao
- Charles E. Schmidt College of Medicine, Florida Atlantic University, USA
| | - Ibrahim M. Shokry
- Charles E. Schmidt College of Medicine, Florida Atlantic University, USA
- Ross University School of Veterinary Medicine, West Indies
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Nguyen JD, Bremer PT, Ducime A, Creehan KM, Kisby BR, Taffe MA, Janda KD. Active vaccination attenuates the psychostimulant effects of α-PVP and MDPV in rats. Neuropharmacology 2016; 116:1-8. [PMID: 27956054 DOI: 10.1016/j.neuropharm.2016.12.005] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2016] [Revised: 12/01/2016] [Accepted: 12/09/2016] [Indexed: 11/20/2022]
Abstract
Recreational use of substituted cathinones continues to be an emerging public health problem in the United States; cathinone derivatives α-pyrrolidinopentiophenone (α-PVP) and 3,4-methylenedioxypyrovalerone (MDPV), which have been linked to human fatalities and show high potential for abuse liability in animal models, are of particular concern. The objective of this study was to develop an immunotherapeutic strategy for attenuating the effects of α-PVP and MDPV in rats, using drug-conjugate vaccines created to generate antibodies with neutralizing capacity. Immunoconjugates (α-PVP-KLH and MDPV-KLH) or the control carrier protein, keyhole limpet hemocyanin (KLH), were administered to groups (N = 12) of male Sprague-Dawley rats on Weeks 0, 2 and 4. Groups were administered α-PVP or MDPV (0.0, 0.25, 0.5, 1.0, 5.0 mg/kg, i.p.) in acute drug challenges and tested for changes in wheel activity. Increased wheel activity produced by α-PVP or MDPV in the controls was attenuated in the α-PVP-KLH and MDPV-KLH vaccinated groups, respectively. Rectal temperature decreases produced by MDPV in the controls were reduced in duration in the MDPV-KLH vaccine group. A separate group (N = 19) was trained to intravenously self-administer α-PVP (0.05, 0.1 mg/kg/inf) and vaccinated with KLH or α-PVP-KLH, post-acquisition. Self-administration in α-PVP-KLH rats was initially higher than in the KLH rats but then significantly decreased following a final vaccine booster, unlike the stable intake of KLH rats. The data demonstrate that active vaccination provides functional protection against the effects of α-PVP and MDPV, in vivo, and recommend additional development of vaccines as potential therapeutics for mitigating the effects of designer cathinone derivatives.
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Affiliation(s)
| | - Paul T Bremer
- Departments of Chemistry and Immunology, The Skaggs Institute for Chemical Biology, Worm Institute for Research and Medicine (WIRM), The Scripps Research Institute, La Jolla, CA, USA
| | - Alex Ducime
- Departments of Chemistry and Immunology, The Skaggs Institute for Chemical Biology, Worm Institute for Research and Medicine (WIRM), The Scripps Research Institute, La Jolla, CA, USA
| | | | - Brent R Kisby
- Committee on the Neurobiology of Addictive Disorders, USA
| | | | - Kim D Janda
- Departments of Chemistry and Immunology, The Skaggs Institute for Chemical Biology, Worm Institute for Research and Medicine (WIRM), The Scripps Research Institute, La Jolla, CA, USA
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Aarde SM, Creehan KM, Vandewater SA, Dickerson TJ, Taffe MA. In vivo potency and efficacy of the novel cathinone α-pyrrolidinopentiophenone and 3,4-methylenedioxypyrovalerone: self-administration and locomotor stimulation in male rats. Psychopharmacology (Berl) 2015; 232:3045-55. [PMID: 25925780 PMCID: PMC4515201 DOI: 10.1007/s00213-015-3944-8] [Citation(s) in RCA: 85] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/27/2015] [Accepted: 04/16/2015] [Indexed: 11/30/2022]
Abstract
RATIONALE Numerous substituted cathinone drugs have appeared in recreational use. This variety is often a response to legal actions; the scheduling of 3,4-methylenedioxypyrovalerone (MDPV; "bath salts") in the USA was followed by the appearance of the closely related drug α-pyrrolidinopentiophenone (alpha-PVP; "flakka"). OBJECTIVES This study aimed to directly compare the efficacy and potency of alpha-PVP with that of MDPV. METHODS Groups of male Wistar rats were trained in the intravenous self-administration (IVSA) alpha-PVP or MDPV under a fixed-ratio 1 schedule of reinforcement. An additional group was examined for locomotor and body temperature responses to noncontingent administration of MDVP or alpha-PVP (1.0, 5.6, and 10.0 mg/kg, i.p.). RESULTS Acquisition of alpha-PVP (0.1 mg/kg/infusion) IVSA resulted in low, yet consistent drug intake and excellent discrimination for the drug-paired lever. Dose substitution (0.05-0.25 mg/kg/infusion) under a fixed-ratio 1 schedule confirmed potency was similar to MDPV in prior studies. In direct comparison to MDPV (0.05 mg/kg/infusion), rats trained on alpha-PVP (0.05 mg/kg/infusion) responded for more infusions but demonstrated similar drug-lever discrimination by the end of acquisition. However, the dose-response (0.018-0.56 mg/kg/infusion) functions of these drugs under a progressive-ratio schedule of reinforcement reflected identical efficacy and potency. Peak locomotor responses to MDPV or alpha-PVP were observed after the 1.0 mg/kg, i.p. dose and lasted ∼2 h. Modest body temperature decreases were of similar magnitude (∼0.75 °C) for each compound. CONCLUSIONS The potency and efficacy of MDPV and alpha-PVP were very similar across multiple assays, predicting that the abuse liability of alpha-PVP will be significant and similar to that of MDPV.
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Affiliation(s)
- Shawn M. Aarde
- Committee on the Neurobiology of Addictive Disorders, The Scripps Research Institute; La Jolla, CA, USA
| | - Kevin M. Creehan
- Committee on the Neurobiology of Addictive Disorders, The Scripps Research Institute; La Jolla, CA, USA
| | - Sophia A. Vandewater
- Committee on the Neurobiology of Addictive Disorders, The Scripps Research Institute; La Jolla, CA, USA
| | - Tobin J. Dickerson
- Department of Chemistry; The Scripps Research Institute; La Jolla, CA, USA
| | - Michael A. Taffe
- Committee on the Neurobiology of Addictive Disorders, The Scripps Research Institute; La Jolla, CA, USA
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Tao R, Shokry IM, Callanan JJ, Adams HD, Ma Z. Mechanisms and environmental factors that underlying the intensification of 3,4-methylenedioxymethamphetamine (MDMA, Ecstasy)-induced serotonin syndrome in rats. Psychopharmacology (Berl) 2015; 232:1245-60. [PMID: 25300903 PMCID: PMC4361258 DOI: 10.1007/s00213-014-3759-z] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/25/2014] [Accepted: 09/23/2014] [Indexed: 01/08/2023]
Abstract
RATIONALE Illicit use of 3,4-methylenedioxymethamphetamine (MDMA, Ecstasy) may cause a mild or severe form of the serotonin syndrome. The syndrome intensity is not just influenced by drug doses but also by environmental factors. OBJECTIVES Warm environmental temperatures and physical activity are features of raves. The purpose of this study was to assess how these two factors can potentially intensify the syndrome. METHODS Rats were administered MDMA at doses of 0.3, 1, or 3 mg/kg and examined in the absence or presence of warm temperature and physical activity. The syndrome intensity was estimated by visual scoring for behavioral syndrome and also instrumentally measuring changes in symptoms of the syndrome. RESULTS Our results showed that MDMA at 3 mg/kg, but not 0.3 or 1 mg/kg, caused a mild serotonin syndrome in rats. Each environmental factor alone moderately intensified the syndrome. When the two factors were combined, the intensification became more severe than each factor alone highlighting a synergistic effect. This intensification was blocked by the 5-HT2A receptor antagonist M100907, competitive N-methyl-D-aspartic acid (NMDA) receptor antagonist CGS19755, autonomic ganglionic blocker hexamethonium, and the benzodiazepine-GABAA receptor agonist midazolam but not by the 5-HT1A receptor antagonist WAY100635 or nicotinic receptor antagonist methyllycaconitine. CONCLUSIONS Our data suggest that, in the absence of environmental factors, the MDMA-induced syndrome is mainly mediated through the serotonergic transmission (5-hydroxytryptamine (5HT)-dependent mechanism) and therefore is relatively mild. Warm temperature and physical activity facilitate serotonergic and other neural systems such as glutamatergic and autonomic transmissions, resulting in intensification of the syndrome (non-5HT mechanisms).
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Affiliation(s)
- Rui Tao
- Charles E. Schmidt College of Medicine, Florida Atlantic University, 777 Glades Road, Boca Raton, FL, 33431, USA,
| | - Ibrahim M. Shokry
- Charles E. Schmidt College of Medicine, Florida Atlantic University, Boca Raton, Florida, USA, School of Veterinary Medicine, Ross University, St. Kitts, West Indies
| | - John J. Callanan
- School of Veterinary Medicine, Ross University, St. Kitts, West Indies
| | - H. Daniel Adams
- Charles E. Schmidt College of Medicine, Florida Atlantic University, Boca Raton, Florida, USA
| | - Zhiyuan Ma
- Charles E. Schmidt College of Medicine, Florida Atlantic University, Boca Raton, Florida, USA
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13
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Miller ML, Moreno AY, Aarde SM, Creehan KM, Vandewater SA, Vaillancourt BD, Wright MJ, Janda KD, Taffe MA. A methamphetamine vaccine attenuates methamphetamine-induced disruptions in thermoregulation and activity in rats. Biol Psychiatry 2013; 73:721-8. [PMID: 23098894 PMCID: PMC3561477 DOI: 10.1016/j.biopsych.2012.09.010] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/21/2012] [Revised: 08/23/2012] [Accepted: 09/07/2012] [Indexed: 10/27/2022]
Abstract
BACKGROUND There are no approved pharmacotherapies for d-methamphetamine (METH) addiction and existing therapies have limited efficacy. Advances in using immunotherapeutic approaches for cocaine and nicotine addiction have stimulated interest in creating a similar approach for METH addiction. This study investigated whether active vaccination against METH could potentially attenuate responses to METH in vivo. METHODS Male Sprague Dawley rats (n = 32) received a four-boost series with one of three candidate anti-METH vaccines (MH2[R], MH6, and MH7) or a control keyhole limpet hemocyanin conjugate vaccine. Effects of METH on rectal temperature and wheel activity at 27°C ambient temperature were determined. The most efficacious vaccine, MH6, was then contrasted with keyhole limpet hemocyanin conjugate vaccine in a subsequent experiment (n = 16), wherein radiotelemetry determined home cage locomotor activity and body temperature at 23°C ambient temperature. RESULTS The MH6 vaccine produced high antibody titers with nanomolar affinity for METH and sequestered METH in the periphery of rats. In experiment 1, the thermoregulatory and psychomotor responses produced by METH at 27°C were blocked in the MH6 group. In experiment 2, METH-induced decreases in body temperature and locomotor activity at 23°C were also attenuated in the MH6 group. A pharmacokinetic study in experiment 2 showed that MH6-vaccinated rats had higher METH serum concentrations, yet lower brain METH concentrations, than control rats, and METH concentrations correlated with individual antibody titer. CONCLUSIONS These data demonstrate that active immunopharmacotherapy provides functional protection against physiological and behavioral disruptions induced by METH.
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Affiliation(s)
- Michelle L Miller
- Committee on the Neurobiology of Addictive Disorders, Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, CA 92037, USA
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14
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Miller ML, Creehan K, Angrish D, Barlow DJ, Houseknecht KL, Dickerson TJ, Taffe MA. Changes in ambient temperature differentially alter the thermoregulatory, cardiac and locomotor stimulant effects of 4-methylmethcathinone (mephedrone). Drug Alcohol Depend 2013; 127:248-53. [PMID: 22832282 PMCID: PMC3491086 DOI: 10.1016/j.drugalcdep.2012.07.003] [Citation(s) in RCA: 94] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/30/2012] [Revised: 07/05/2012] [Accepted: 07/09/2012] [Indexed: 12/11/2022]
Abstract
BACKGROUND The substituted cathinone compound known as mephedrone (4-methylmethcathinone; 4-MMC) has become popular with recreational users of psychomotor-stimulant compounds. Only recently have the first preclinical studies provided information about this drug in the scientific literature; nevertheless, media reports have led to drug control actions in the UK and across several US states. Rodent studies indicate that 4-MMC exhibits neuropharmacological similarity to 3,4-methylenedioxymethamphetamine (MDMA) and prompt investigation of the thermoregulatory, cardiac and locomotor effects of 4-MMC. This study focuses on the role of ambient temperature, which has been shown to shift the effects of MDMA from hyperthermic to hypothermic. METHODS Male Sprague-Dawley rats were monitored after subcutaneous administration of 4-MMC (1.0-5.6 mg/kg) using an implantable radiotelemetry system under conditions of low (20 °C) and high (30 °C) ambient temperature. RESULTS A pharmacokinetic study found a T(max) of 0.25 h and a C(max) of 1206 ng/ml after 5.6 mg/kg 4-MMC. A dose-dependent reduction of body temperature was produced by 4-MMC at 20 °C but there was no temperature change at 30 °C. Increased locomotor activity was observed after 4-MMC administration under both ambient temperatures, however, significantly more activity was observed at 30 °C. Heart rate was slowed by 1.0 and 5.6 mg/kg 4-MMC at 20°C, and was slower in the 30 °C vs. 20 °C condition across all treatments. CONCLUSION These results show that the cathinone analog 4-MMC exhibits in vivo thermoregulatory properties that are distinct from those produced by MDMA.
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Affiliation(s)
- M. L. Miller
- Committee on the Neurobiology of Addictive Disorders, The Scripps Research Institute, La Jolla, CA, USA
| | - K.M. Creehan
- Committee on the Neurobiology of Addictive Disorders, The Scripps Research Institute, La Jolla, CA, USA
| | - D. Angrish
- Department of Chemistry, The Scripps Research Institute, La Jolla, CA, USA
| | - D. J. Barlow
- Department of Pharmaceutical Sciences; University of New England; Portland, ME 04103
| | - K. L. Houseknecht
- Department of Pharmaceutical Sciences; University of New England; Portland, ME 04103
| | - T. J. Dickerson
- Department of Chemistry, The Scripps Research Institute, La Jolla, CA, USA
| | - M. A. Taffe
- Committee on the Neurobiology of Addictive Disorders, The Scripps Research Institute, La Jolla, CA, USA
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15
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Huang PK, Aarde SM, Angrish D, Houseknecht KL, Dickerson TJ, Taffe MA. Contrasting effects of d-methamphetamine, 3,4-methylenedioxymethamphetamine, 3,4-methylenedioxypyrovalerone, and 4-methylmethcathinone on wheel activity in rats. Drug Alcohol Depend 2012; 126:168-75. [PMID: 22664136 PMCID: PMC3439532 DOI: 10.1016/j.drugalcdep.2012.05.011] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/14/2012] [Revised: 05/10/2012] [Accepted: 05/11/2012] [Indexed: 10/28/2022]
Abstract
BACKGROUND Reports from U.S., U.K. and European drug policy entities, and ongoing media accounts, show increasing recreational use of 4-methylmethcathinone (4-MMC, mephedrone) and 3,4-methylenedioxypyrovalerone (MDPV). Severe sympathomimetic symptoms, hallucinations, psychoses, and even deaths have been reported, yet little scientific information is available on the effects of these compounds in laboratory models. Available studies on the neurochemistry of these drugs show that 4-MMC and MDPV enhance DA neurotransmission, while 4-MMC additionally enhances 5-HT neurotransmission--a pattern much like that reported for methamphetamine versus 3,4-methylenedioxymethamphetamine (MDMA). As is the case for designer amphetamines, these neurochemical distinctions may predict differential potential for repetitive versus episodic abuse and distinct lasting toxicities. METHODS This study determined relative locomotor stimulant effects of 4-MMC (1-10 mg/kg, s.c.) and MDPV (0.5-5.6 mg/kg, s.c.), in comparison with d-methamphetamine (MA; 0.5-5.6 mg/kg, s.c.) and MDMA (1-7.5 mg/kg, s.c.) on a measure of locomotor activity--voluntary wheel running--in male Wistar rats (N=8). RESULTS Compared to counts of wheel rotations after saline, a biphasic change in the pattern of counts was observed after injections of MA and MDPV, with relatively higher counts following lower doses and lower counts following the highest dose. However, monophasic, dose-dependent reductions in counts were observed in response to injections of MDMA and 4-MMC. CONCLUSION Thus, voluntary wheel running yielded the same categorical distinctions for these drugs as did prior experiments testing the effects of these drugs on monoaminergic neurotransmission. These data indicate that MDPV produces prototypical locomotor stimulant effects whereas 4-MMC is more similar to the entactogen MDMA.
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Affiliation(s)
- Pai-Kai Huang
- Committee on the Neurobiology of Addictive Disorders, The Scripps Research Institute, University of New England
| | - Shawn M. Aarde
- Committee on the Neurobiology of Addictive Disorders, The Scripps Research Institute, University of New England
| | - Deepshikha Angrish
- Department of Chemistry, The Scripps Research Institute, University of New England
| | | | - Tobin J. Dickerson
- Department of Chemistry, The Scripps Research Institute, University of New England
| | - Michael A. Taffe
- Committee on the Neurobiology of Addictive Disorders, The Scripps Research Institute, University of New England
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16
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Wright MJ, Angrish D, Aarde SM, Barlow DJ, Buczynski MW, Creehan KM, Vandewater SA, Parsons LH, Houseknecht KL, Dickerson TJ, Taffe MA. Effect of ambient temperature on the thermoregulatory and locomotor stimulant effects of 4-methylmethcathinone in Wistar and Sprague-Dawley rats. PLoS One 2012; 7:e44652. [PMID: 22952999 PMCID: PMC3432134 DOI: 10.1371/journal.pone.0044652] [Citation(s) in RCA: 78] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2012] [Accepted: 08/06/2012] [Indexed: 11/24/2022] Open
Abstract
The drug 4-methylmethcathinone (4-MMC; aka, mephedrone, MMCAT, “plant food”, “bath salts”) is a recent addition to the list of popular recreational psychomotor-stimulant compounds. Relatively little information about this drug is available in the scientific literature, but popular media reports have driven recent drug control actions in the UK and several US States. Online user reports of subjective similarity to 3,4-methylenedioxymethamphetamine (MDMA, “Ecstasy”) prompted the current investigation of the thermoregulatory and locomotor effects of 4-MMC. Male Wistar and Sprague-Dawley rats were monitored after subcutaneous administration of 4-MMC (1–10 mg/kg ) using an implantable radiotelemetry system under conditions of low (23°C) and high (27°C) ambient temperature. A reliable reduction of body temperature was produced by 4-MMC in Wistar rats at 23°C or 27°C with only minimal effect in Sprague-Dawley rats. Increased locomotor activity was observed after 4-MMC administration in both strains with significantly more activity produced in the Sprague-Dawley strain. The 10 mg/kg s.c. dose evoked greater increase in extracellular serotonin, compared with dopamine, in the nucleus accumbens. Follow-up studies confirmed that the degree of locomotor stimulation produced by 10 mg/kg 4-MMC was nearly identical to that produced by 1 mg/kg d-methamphetamine in each strain. Furthermore, hypothermia produced by the serotonin 1A/7 receptor agonist 8-hydroxy-N,N-dipropyl-2-aminotetralin (8-OH-DPAT) was similar in each strain. These results show that the cathinone analog 4-MMC exhibits thermoregulatory and locomotor properties that are distinct from those established for methamphetamine or MDMA in prior work, despite recent evidence of neuropharmacological similarity with MDMA.
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Affiliation(s)
- M. Jerry Wright
- Committee on the Neurobiology of Addictive Disorders, The Scripps Research Institute, La Jolla, California, United States of America
| | - Deepshikha Angrish
- Department of Chemistry, The Scripps Research Institute, La Jolla, California, United States of America
| | - Shawn M. Aarde
- Committee on the Neurobiology of Addictive Disorders, The Scripps Research Institute, La Jolla, California, United States of America
| | - Deborah J. Barlow
- Department of Pharmaceutical Sciences, University of New England, Portland, Maine, United States of America
| | - Matthew W. Buczynski
- Committee on the Neurobiology of Addictive Disorders, The Scripps Research Institute, La Jolla, California, United States of America
| | - Kevin M. Creehan
- Committee on the Neurobiology of Addictive Disorders, The Scripps Research Institute, La Jolla, California, United States of America
| | - Sophia A. Vandewater
- Committee on the Neurobiology of Addictive Disorders, The Scripps Research Institute, La Jolla, California, United States of America
| | - Loren H. Parsons
- Committee on the Neurobiology of Addictive Disorders, The Scripps Research Institute, La Jolla, California, United States of America
| | - Karen L. Houseknecht
- Department of Pharmaceutical Sciences, University of New England, Portland, Maine, United States of America
| | - Tobin J. Dickerson
- Department of Chemistry, The Scripps Research Institute, La Jolla, California, United States of America
| | - Michael A. Taffe
- Committee on the Neurobiology of Addictive Disorders, The Scripps Research Institute, La Jolla, California, United States of America
- * E-mail:
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17
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Miller ML, Vaillancourt BD, Wright MJ, Aarde SM, Vandewater SA, Creehan KM, Taffe MA. Reciprocal inhibitory effects of intravenous d-methamphetamine self-administration and wheel activity in rats. Drug Alcohol Depend 2012; 121:90-6. [PMID: 21899959 PMCID: PMC3235246 DOI: 10.1016/j.drugalcdep.2011.08.013] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/18/2011] [Revised: 08/12/2011] [Accepted: 08/12/2011] [Indexed: 11/23/2022]
Abstract
BACKGROUND Some epidemiological and cessation studies suggest physical exercise attenuates or prevents recreational drug use in humans. Preclinical studies indicate that wheel activity reduces cocaine self-administration in rats; this may, however, require the establishment of compulsive wheel activity. METHODS Effects of concurrent wheel activity on intravenous d-methamphetamine (METH) self-administration were examined in male Wistar and Sprague Dawley rats with negligible prior wheel experience. Wistar rats self-administered METH (0.05 mg/kg/inf) under a fixed-ratio 1 (FR1) schedule with concurrent access to an activity wheel during sessions 1-14, 8-21 or 15-21. Control rats which did not self-administer METH had access to an activity wheel during sessions 1-14, 8-21 or 15-28. Sprague Dawley rats self-administered METH (0.1 mg/kg/inf) under FR1 for 14 sessions with either concurrent access to a locked or an unlocked activity wheel. RESULTS METH self-administration was lower when the wheel was available concurrently from the start of self-administration training in both strains, even though Sprague Dawley rats self-administered twice as many METH infusions and ran one-sixth as much on the wheel compared to Wistar rats. Wheel access initiated after 7 or 14 days had no effect on METH self-administration in Wistar rats. Wheel activity was significantly reduced in these groups compared with the group with concurrent wheel and METH access for the first 14 sessions. CONCLUSIONS These data show that METH self-administration is reduced by exercise if initiated from the start of self-administration and that prior METH self-administration experience interferes with the value of exercise as a reinforcer.
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Affiliation(s)
- M L Miller
- Committee on the Neurobiology of Addictive Disorders, The Scripps Research Institute, La Jolla, CA 92037, USA
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