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van Amsterdam J, van den Brink W. Explaining the high mortality among opioid-cocaine co-users compared to opioid-only users. A systematic review. J Addict Dis 2024:1-11. [PMID: 38504419 DOI: 10.1080/10550887.2024.2331522] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/21/2024]
Abstract
RATIONALE The opioid crisis in North America has recently seen a fourth wave, which is dominated by drug-related deaths due to the combined use of illicitly manufactured fentanyl [IMF] and stimulants such as cocaine and methamphetamine. OBJECTIVES A systematic review addressing the question why drug users combine opioids and stimulants and why the combination results in such a high overdose mortality: from specific and dangerous pharmacokinetic or pharmacodynamic interactions or from accidental poisoning? RESULTS Motives for the combined use include a more intensive high or rush when used at the same time, and some users have the unfounded and dangerous belief that co-use of stimulants will counteract opioid-induced respiratory depression. Overdose deaths due to combined (intravenous) use of opioids and stimulants are not likely to be caused by specific pharmacokinetic or pharmacodynamic interactions between the two drugs and it is unlikely that the main cause of overdose deaths is due to accidental poisoning. CONCLUSION The unexpectedly high overdose rates in this population could not be attributed to accidental overdosing or pharmacokinetic/pharmacodynamic interactions. The most likely explanation for the high rate of drug-related deaths in opioid-cocaine co-users is careless overdosing with either cocaine, opioid(s) or both, probably facilitated by the high level of preexisting impulsivity in these co-users and a further acute increase in impulsivity following cocaine use. The primary corollary is that cocaine users should avoid IMF use in the same time window. In addition, IMF users should refrain from cocaine use to avoid impulsive IMF overdosing.
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Affiliation(s)
- Jan van Amsterdam
- Department of Psychiatry, Amsterdam UMC, Location Academic Medical Center, Amsterdam Neuroscience, Research Program Compulsivity, Impulsivity & Attention, Amsterdam, The Netherlands
| | - Wim van den Brink
- Department of Psychiatry, Amsterdam UMC, Location Academic Medical Center, Amsterdam Neuroscience, Research Program Compulsivity, Impulsivity & Attention, Amsterdam, The Netherlands
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2
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Shastry S, Shulman J, Aldy K, Brent J, Wax P, Manini AF. Psychostimulant drug co-ingestion in non-fatal opioid overdose. DRUG AND ALCOHOL DEPENDENCE REPORTS 2024; 10:100223. [PMID: 38463635 PMCID: PMC10920112 DOI: 10.1016/j.dadr.2024.100223] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/15/2024] [Accepted: 02/19/2024] [Indexed: 03/12/2024]
Abstract
Introduction In 2019, there were over 16,000 deaths from psychostimulant overdose with 53.5% also involving an opioid. Given the substantial mortality stemming from opioid and psychostimulant co-exposure, evaluation of clinical management in this population is critical but remains understudied. This study aims to characterize and compare clinical management and outcomes in emergency department (ED) overdose patients with analytically confirmed exposure to both opioids and psychostimulants with those exposed to opioids alone. Methods This was a secondary analysis of a prospective consecutive cohort of ED patients age 18+ with opioid overdose at 9 hospital sites from September 21, 2020 to August 17, 2021. Toxicologic analysis was performed using liquid chromatography quadrupole time-of-flight mass spectrometry. Patients were divided into opioid-only (OO) and opioid plus psychostimulants (OS) groups. The primary outcome was total naloxone bolus dose administered. Secondary outcomes included endotracheal intubation, cardiac arrest, troponin elevation, and abnormal presenting vital signs. We employed t-tests, chi-squared analyses and multivariable regression models to compare outcomes between OO and OS groups. Results Of 378 enrollees with confirmed opioid overdose, 207 (54.8%) had psychostimulants present. OO patients were significantly older (mean 45.2 versus 40.6 years, p < 0.01). OS patients had significantly higher total naloxone requirements (mean total dose 2.79 mg versus 2.12 mg, p = 0.009). There were no significant differences in secondary outcomes. Conclusion Approximately half of ED patients with confirmed opioid exposures were also positive for psychostimulants. Patients in the OS group required significantly higher naloxone doses, suggesting potential greater overdose severity.
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Affiliation(s)
- Siri Shastry
- Department of Emergency Medicine, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Joshua Shulman
- University of Pittsburgh Medical Center, Pittsburgh, PA, USA
| | - Kim Aldy
- American College of Medical Toxicology, Phoenix, AZ, USA
- Department of Emergency Medicine, Baylor University Medical Center, Dallas, TX, USA
| | - Jeffrey Brent
- University of Colorado School of Medicine, Aurora, CO, USA
| | - Paul Wax
- American College of Medical Toxicology, Phoenix, AZ, USA
- Department of Emergency Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Alex F. Manini
- Department of Emergency Medicine, Icahn School of Medicine at Mount Sinai, New York, NY, USA
- Division of Medical Toxicology, Department of Emergency Medicine, Icahn School of Medicine at Mount Sinai, Elmhurst Hospital Center, New York, NY, USA
| | - On behalf of the Toxicology Investigators Consortium Fentalog Study Group
- Department of Emergency Medicine, Icahn School of Medicine at Mount Sinai, New York, NY, USA
- University of Pittsburgh Medical Center, Pittsburgh, PA, USA
- American College of Medical Toxicology, Phoenix, AZ, USA
- Department of Emergency Medicine, Baylor University Medical Center, Dallas, TX, USA
- University of Colorado School of Medicine, Aurora, CO, USA
- Department of Emergency Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA
- Division of Medical Toxicology, Department of Emergency Medicine, Icahn School of Medicine at Mount Sinai, Elmhurst Hospital Center, New York, NY, USA
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3
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Deconinck E, Lievens S, Canfyn M, Van Campenhout P, Debehault L, Gremaux L, Balcaen M. Full Characterisation of Heroin Samples Using Infrared Spectroscopy and Multivariate Calibration. Molecules 2024; 29:1116. [PMID: 38474628 DOI: 10.3390/molecules29051116] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2024] [Revised: 02/23/2024] [Accepted: 02/28/2024] [Indexed: 03/14/2024] Open
Abstract
The analysis of heroin samples, before use in the protected environment of user centra, could be a supplementary service in the context of harm reduction. Infrared spectroscopy hyphenated with multivariate calibration could be a valuable asset in this context, and therefore 125 heroin samples were collected directly from users and analysed with classical chromatographic techniques. Further, Mid-Infrared spectra were collected for all samples, to be used in Partial Least Squares (PLS) modelling, in order to obtain qualitative and quantitative models based on real live samples. The approach showed that it was possible to identify and quantify heroin in the samples based on the collected spectral data and PLS modelling. These models were able to identify heroin correctly for 96% of the samples of the external test set with precision, specificity and sensitivity values of 100.0, 75.0 and 95.5%, respectively. For regression, a root mean squared error of prediction (RMSEP) of 0.04 was obtained, pointing at good predictive properties. Furthermore, during mass spectrometric screening, 10 different adulterants and impurities were encountered. Using the spectral data to model the presence of each of these resulted in performant models for seven of them. All models showed promising correct-classification rates (between 92 and 96%) and good values for sensitivity, specificity and precision. For codeine and morphine, the models were not satisfactory, probably due to the low concentration of these impurities as a consequence of acetylation. For methacetin, the approach failed.
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Affiliation(s)
- Eric Deconinck
- Sciensano, Scientific Direction Chemical and Physical Health Risks, Service of Medicines and Health Products, J. Wytsmanstraat 14, B-1050 Brussels, Belgium
| | - Sybrien Lievens
- Sciensano, Scientific Direction Chemical and Physical Health Risks, Service of Medicines and Health Products, J. Wytsmanstraat 14, B-1050 Brussels, Belgium
- VUB, Faculty of Sciences and Bio-Engineering, Department Chemistry, Analytical, Environmental and Geo-Chemistry, Pleinlaan 2, B-1050 Brussels, Belgium
| | - Michael Canfyn
- Sciensano, Scientific Direction Chemical and Physical Health Risks, Service of Medicines and Health Products, J. Wytsmanstraat 14, B-1050 Brussels, Belgium
| | - Peter Van Campenhout
- Sciensano, Scientific Direction Chemical and Physical Health Risks, Service of Medicines and Health Products, J. Wytsmanstraat 14, B-1050 Brussels, Belgium
| | - Loic Debehault
- Sciensano, Scientific Direction Chemical and Physical Health Risks, Service of Medicines and Health Products, J. Wytsmanstraat 14, B-1050 Brussels, Belgium
| | - Lies Gremaux
- Sciensano, Scientific Direction Epidemiology and Public Health, Service Lifestyle and Chronic Diseases, J. Wytsmanstraat 14, B-1050 Brussels, Belgium
| | - Margot Balcaen
- Sciensano, Scientific Direction Epidemiology and Public Health, Service Lifestyle and Chronic Diseases, J. Wytsmanstraat 14, B-1050 Brussels, Belgium
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4
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Hoetger C, Bono RS, White AM, Barnes AJ, Cobb CO. The interaction of nicotine concentration and device power on electronic nicotine delivery system (ENDS) abuse liability among exclusive ENDS users and dual users of ENDS and combustible cigarettes. Exp Clin Psychopharmacol 2022; 30:973-982. [PMID: 34647773 PMCID: PMC9284402 DOI: 10.1037/pha0000523] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Open-system electronic nicotine delivery systems (ENDS) permit modifications to device characteristics such as power, potentially increasing nicotine and toxicant delivery. Limiting liquid nicotine concentration may carry unintended consequences by prompting users to increase device power to increase nicotine delivery. This study examined the abuse liability of ENDS across nicotine concentration and power settings. In a clinical laboratory study, n = 19 exclusive ENDS users and n = 13 dual ENDS/cigarette users, aged 21-55 completed four Latin-square ordered conditions that varied by liquid nicotine concentration (10 mg/ml [low], 30 mg/ml [high]) and device power (15 watts [low], 30 watts [high]), that were followed by a fifth own brand (OB) condition. A progressive ratio task (PRT) using bar presses to earn ENDS puffs was used to assess abuse liability and compare between conditions using mixed effects linear regressions. The low nicotine/high watt condition was associated with a significantly higher number of bar presses and puffs earned relative to the OB ENDS, high nicotine/high watt, and high nicotine/low watt conditions (p < .05). Findings appeared to be driven largely by exclusive ENDS users; most comparisons were not significant among dual users. Participants worked significantly harder for puffs of low nicotine/high watt ENDS, highlighting previous findings that suggest limiting liquid nicotine concentration without addressing power settings may be insufficient to reduce the abuse liability of ENDS. (PsycInfo Database Record (c) 2022 APA, all rights reserved).
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Affiliation(s)
- Cosima Hoetger
- Department of Psychology, Virginia Commonwealth University
- Center for the Study of Tobacco Products, Virginia Commonwealth University
| | - Rose S. Bono
- Center for the Study of Tobacco Products, Virginia Commonwealth University
- Department of Health Behavior and Policy, Virginia Commonwealth University
| | - Augustus M. White
- Center for the Study of Tobacco Products, Virginia Commonwealth University
- Department of Health Behavior and Policy, Virginia Commonwealth University
| | - Andrew J. Barnes
- Center for the Study of Tobacco Products, Virginia Commonwealth University
- Department of Health Behavior and Policy, Virginia Commonwealth University
| | - Caroline O. Cobb
- Department of Psychology, Virginia Commonwealth University
- Center for the Study of Tobacco Products, Virginia Commonwealth University
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5
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Interactions between opioids and stimulants: Behavioral pharmacology of abuse-related effects. ADVANCES IN PHARMACOLOGY (SAN DIEGO, CALIF.) 2022; 93:1-33. [PMID: 35341563 DOI: 10.1016/bs.apha.2021.10.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Opioid abuse continues to be a significant public health challenge, with rates of opioid-related overdose deaths increasing continuously over the last two decades. There also has been a sharp increase in overdose deaths involving stimulant drugs, primarily cocaine and methamphetamine. Recent estimates indicate a high prevalence of co-use of opioids and stimulants, which is a particularly complex problem. Behavioral pharmacology research over the last few decades has characterized interactions between opioids and stimulants as well as evaluated potential treatments. This chapter describes interactions between opioids and stimulants, with a focus on pre-clinical studies of abuse-related behavioral effects using self-administration, reinstatement, drug discrimination, place conditioning, and intracranial self-stimulation paradigms in laboratory animals. In general, the literature provides substantial evidence of mutual enhancement between opioids and stimulants for abuse-related effects, although such results are not ubiquitous. Enhanced abuse-related effects could manifest in many ways including engaging in drug seeking and taking behaviors with greater persistence, effort, and motivation and/or increased likelihood of relapse. Moreover, studies on opioid/stimulant combinations set the stage for evaluating potential treatments for polysubstance use. Behavioral pharmacology research has proven invaluable for elucidating these relationships using rigorous experimental designs and quantitative analyses of pharmacological and behavioral data.
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6
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Doyle MR, Gannon BM, Mesmin MP, Collins GT. Application of dose-addition analyses to characterize the abuse-related effects of drug mixtures. J Exp Anal Behav 2022; 117:442-456. [PMID: 35142382 PMCID: PMC9327442 DOI: 10.1002/jeab.741] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2021] [Revised: 01/07/2022] [Accepted: 01/11/2022] [Indexed: 11/12/2022]
Abstract
Polysubstance use makes up a majority of drug use, yet relatively few studies investigate the abuse-related effects of drug mixtures. Dose-addition analyses provide a rigorous and quantitative method to determine the nature of the interaction (i.e., supraadditive, additive, or subadditive) between two or more drugs. As briefly reviewed here, studies in rhesus monkeys have applied dose-addition analyses to group level data to characterize the nature of the interaction between the reinforcing effects of stimulants and opioids (e.g., mixtures of cocaine + heroin). Building upon these foundational studies, more recent work has applied dose-addition analyses to better understand the nature of the interaction between caffeine and illicit stimulants such as MDPV and methamphetamine in rats. In addition to utilizing a variety of operant procedures, including drug discrimination, drug self-administration, and drug-primed reinstatement, these studies have incorporated potency and effectiveness ratios as a method for both statistical analysis and visualization of departures from additivity at both the group and individual subject level. As such, dose-addition analyses represent a powerful and underutilized approach to quantify the nature of drug-drug interactions that can be applied to a variety of abuse-related endpoints in order to better understand the behavioral pharmacology of polysubstance use.
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Affiliation(s)
- Michelle R Doyle
- Department of Pharmacology, University of Texas Health Science Center at San Antonio.,South Texas Veterans Health Care System, San Antonio
| | - Brenda M Gannon
- Department of Pharmacology, University of Texas Health Science Center at San Antonio
| | - Melson P Mesmin
- Department of Pharmacology, University of Texas Health Science Center at San Antonio
| | - Gregory T Collins
- Department of Pharmacology, University of Texas Health Science Center at San Antonio.,South Texas Veterans Health Care System, San Antonio
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7
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Seaman RW, Lordson C, Collins GT. Modeling Stimulant and Opioid Co-use in Rats Provided Concurrent Access to Methamphetamine and Fentanyl. Front Psychiatry 2022; 13:814574. [PMID: 35237191 PMCID: PMC8884160 DOI: 10.3389/fpsyt.2022.814574] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/13/2021] [Accepted: 01/19/2022] [Indexed: 11/21/2022] Open
Abstract
Concurrent use of stimulants (e.g., methamphetamine) and opioids (e.g., fentanyl) has become increasingly common in recent years and continues to pose an enormous health burden, worldwide. Despite the prevalence, relatively little is known about interactions between the reinforcing effects of stimulants and opioids in this pattern of polysubstance use. The goals of the current study were to evaluate the relative reinforcing and relapse-related effects of methamphetamine and fentanyl using a concurrent access, drug-vs.-drug choice procedure. Male Sprague-Dawley rats were first allowed to acquire self-administration for either 0.1 mg/kg/infusion methamphetamine or 0.0032 mg/kg/infusion fentanyl, independently, after which concurrent access to both drugs was provided. When training doses of methamphetamine and fentanyl were concurrently available, a subset of rats self-administered both drugs, either within a session or alternating across sessions, whereas the remaining rats responded exclusively for one drug. When the cost of the preferred drug was increased (i.e., unit dose reduced), or the cost of the non-preferred drug was decreased (i.e., unit dose increased), choice was largely allocated toward the cheaper alternative. Following extinction of responding, methamphetamine- and fentanyl-paired cues reinstated responding on both levers. Responding reinstated by a priming injection of methamphetamine or fentanyl allocated more responding to the lever previously reinforced by the priming drug. The current studies suggest that choice of methamphetamine and fentanyl is largely allocated to the cheaper alternative, although more co-use was observed than would be expected for economic substitutes. Moreover, they lay the groundwork for more fully evaluating interactions between commonly co-abused drugs (e.g., stimulants and opioids) in order to better understand the determinants of polysubstance use and develop effective treatment strategies for individuals suffering from a polysubstance use disorder.
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Affiliation(s)
- Robert W Seaman
- Department of Pharmacology, The University of Texas Health Science Center at San Antonio, San Antonio, TX, United States.,South Texas Veterans Health Care System, San Antonio, TX, United States
| | - Chris Lordson
- Department of Pharmacology, The University of Texas Health Science Center at San Antonio, San Antonio, TX, United States
| | - Gregory T Collins
- Department of Pharmacology, The University of Texas Health Science Center at San Antonio, San Antonio, TX, United States.,South Texas Veterans Health Care System, San Antonio, TX, United States
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8
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Bjorness TE, Greene RW. Interaction between cocaine use and sleep behavior: A comprehensive review of cocaine's disrupting influence on sleep behavior and sleep disruptions influence on reward seeking. Pharmacol Biochem Behav 2021; 206:173194. [PMID: 33940055 DOI: 10.1016/j.pbb.2021.173194] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/06/2020] [Revised: 04/20/2021] [Accepted: 04/27/2021] [Indexed: 12/21/2022]
Abstract
Dopamine, orexin (hypocretin), and adenosine systems have dual roles in reward and sleep/arousal suggesting possible mechanisms whereby drugs of abuse may influence both reward and sleep/arousal. While considerable variability exists across studies, drugs of abuse such as cocaine induce an acute sleep loss followed by an immediate recovery pattern that is consistent with a normal response to loss of sleep. Under more chronic cocaine exposure conditions, an abnormal recovery pattern is expressed that includes a retention of sleep disturbance under withdrawal and into abstinence conditions. Conversely, experimentally induced sleep disturbance can increase cocaine seeking. Thus, complementary, sleep-related therapeutic approaches may deserve further consideration along with development of non-human models to better characterize sleep disturbance-reward seeking interactions across drug experience.
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Affiliation(s)
- Theresa E Bjorness
- Research Service, VA North Texas Health Care System, Dallas, TX 75126, USA; Department of Psychiatry, University of Texas Southwestern Medical Center, Dallas, TX 75390-9111, USA.
| | - Robert W Greene
- Department of Psychiatry, University of Texas Southwestern Medical Center, Dallas, TX 75390-9111, USA; Department of Neuroscience, Peter O'Donnell Jr. Brain Institute, University of Texas Southwestern Medical Center, Dallas, TX 75390-9111, USA; International Institute for Integrative Sleep Medicine, University of Tsukuba, Tsukuba, 305-8577, Japan
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9
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Silverstein SM, Daniulaityte R, Getz K, Zule W. "It's Crazy What Meth Can Help You Do": Lay Beliefs, Practices, and Experiences of Using Methamphetamine to Self-Treat Symptoms of Opioid Withdrawal. Subst Use Misuse 2021; 56:1687-1696. [PMID: 34279180 DOI: 10.1080/10826084.2021.1949612] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
BACKGROUND Across the U.S., methamphetamine use is expanding among people who use illicit opioids (PWUIO). Motives for methamphetamine use must be contextualized within the experiences of PWUIO, who may use methamphetamine not only to achieve euphoria, but also as a tactic of self-management. The overall aim of this study is to contextualize lay beliefs, practices, and experiences of methamphetamine use as a form of self-treatment of symptoms related to chronic opioid use among PWUIO in the Dayton Metro Area of Southwest Ohio, an epicenter of the ongoing opioid crisis. METHODS This paper draws on two phases of interviews conducted with 38 individuals who use both heroin/fentanyl and methamphetamine. This paper primarily analyzes qualitative data but includes supplementary information from the structured interview component. Qualitative interview sections were transcribed in their entirety and thematically analyzed. RESULTS Participants described learning about methamphetamine as a tactic to treat opioid withdrawal symptoms through social networks and through personal experimentation. Many participants suggested that methamphetamine was helpful in relieving exhaustion, alleviating some acute physical symptoms of opioid withdrawal, and providing a psychological distraction, although some admitted that methamphetamine use could incur additional health risks. To effectively use methamphetamine as a tactic of self-treatment, participants emphasized the importance of timing and dosing. DISCUSSION Among PWUIO in the Dayton area, methamphetamine use as a tactic to self-manage opioid withdrawal must be studied in relation to historical and evolving patterns of illicit opioid use and associated risks. More research is needed to understand the long-term health impacts of this emergent practice of polydrug use.
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Affiliation(s)
- Sydney M Silverstein
- Center for Interventions, Treatment, and Addictions Research/Department of Population and Public Health Sciences, Wright State University Boonshoft School of Medicine, Dayton, Ohio, USA
| | | | - Kylie Getz
- Wright State University, Dayton, Ohio, USA
| | - William Zule
- Center for Global Health, RTI International, Durham, North Carolina, USA
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10
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Moretti J, Poh EZ, Bolland SJ, Harvey AR, Albrecht MA, Rodger J. Concurrent LI-rTMS induces changes in c-Fos expression but not behavior during a progressive ratio task with adult ephrin-A2A5 -/- mice. Behav Brain Res 2020; 400:113011. [PMID: 33181182 DOI: 10.1016/j.bbr.2020.113011] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2020] [Revised: 10/04/2020] [Accepted: 11/05/2020] [Indexed: 12/28/2022]
Abstract
Changes within the dopaminergic system induced by repetitive transcranial magnetic stimulation (rTMS) may contribute to its therapeutic effects; however, dopamine-related behavioral effects of rTMS have not been widely investigated. We recently showed that ephrin-A2A5-/- mice completed significantly fewer trials in a visual task than wildtype mice, and that concurrent low-intensity (LI-) rTMS during the task could partially rescue the abnormal behavior [Poh et al. 2018, eNeuro, vol. 5]. Here, we investigated whether the behavioral differences in ephrin-A2A5-/- mice are due to abnormal motivation, primarily a dopamine-modulated behavior, and whether LI-rTMS would increase motivation. Ephrin-A2A5-/- and wildtype mice underwent 14 daily sessions of progressive ratio (PR) tasks and received either sham or LI-rTMS during the first 10 min. Ephrin-A2A5-/- mice responded more than wildtype comparisons, and LI-rTMS did not influence task performance for either strain. Therefore concurrent stimulation does not influence motivation in a PR task. However, ephrin-A2A5-/- mice did have abnormal performance in the PR tasks after a change in the PR schedule which suggests perseverative behavior. We stained for c-Fos in the prelimbic area (PrL), ventral tegmental area and nucleus accumbens (NAc) core and shell to examine neuronal activity from the final PR session. Sham ephrin-A2A5-/- mice had lower c-Fos expression in the PrL and NAc vs. wildtype mice. Ephrin-A2A5-/- mice that received LI-rTMS showed c-Fos expression closer to wildtype levels in the NAc. Combined with high PR performance, ephrin-A2A5-/- mice show an abnormal shift to habitual responding and LI-rTMS may attenuate this shift.
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Affiliation(s)
- Jessica Moretti
- School of Biological Sciences, The University of Western Australia, Perth, WA, Australia; School of Human Sciences, The University of Western Australia, Perth, WA, Australia; Perron Institute for Neurological and Translational Science, Perth, WA, Australia
| | - Eugenia Z Poh
- School of Biological Sciences, The University of Western Australia, Perth, WA, Australia; School of Human Sciences, The University of Western Australia, Perth, WA, Australia; Perron Institute for Neurological and Translational Science, Perth, WA, Australia
| | - Samuel J Bolland
- School of Biological Sciences, The University of Western Australia, Perth, WA, Australia; Perron Institute for Neurological and Translational Science, Perth, WA, Australia
| | - Alan R Harvey
- School of Human Sciences, The University of Western Australia, Perth, WA, Australia; Perron Institute for Neurological and Translational Science, Perth, WA, Australia
| | | | - Jennifer Rodger
- School of Biological Sciences, The University of Western Australia, Perth, WA, Australia; Perron Institute for Neurological and Translational Science, Perth, WA, Australia.
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11
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Jaime S, Vena AA, Gonzales RA. Intravenous Ethanol Administration and Operant Self-Administration Alter Extracellular Norepinephrine Concentration in the Mesocorticolimbic Systems of Male Long Evans Rats. Alcohol Clin Exp Res 2020; 44:1529-1539. [PMID: 32573991 DOI: 10.1111/acer.14397] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2020] [Accepted: 06/10/2020] [Indexed: 11/29/2022]
Abstract
BACKGROUND Norepinephrine has been suggested to regulate ethanol (EtOH)-related behaviors, but little is known about the effects of EtOH on norepinephrine release in mesocortical and mesolimbic brain areas that are targets of EtOH actions. METHODS We used in vivo microdialysis to examine the effects of EtOH on extracellular norepinephrine concentrations in mesocorticolimbic brain regions of male Long Evans rats. We determined the effects of intravenous infusion of saline or EtOH in the medial prefrontal cortex (mPFC) and the basal forebrain. We also measured dialysate norepinephrine concentrations during operant self-administration of EtOH in the mPFC. RESULTS Intravenous infusion (1 or 0.25 ml/min) of 1.0 g/kg EtOH stimulated an increase in dialysate norepinephrine in mPFC and in basal forebrain. In the basal forebrain, an infusion of 0.5 g/kg EtOH did not stimulate dialysate norepinephrine concentrations. In both regions, saline infusions did not increase dialysate norepinephrine concentrations. In the behavioral experiment, 1 week of experience with operant self-administration of sweetened EtOH resulted in an apparent reduction in basal dialysate norepinephrine concentrations in the mPFC relative to the sucrose control. Dialysate norepinephrine increased during the transfer from home cage to the operant chamber in all groups. CONCLUSIONS We conclude that acute EtOH stimulates both the locus coeruleus (which projects to the mPFC) and the nucleus tractus solitarius (which projects to the basal forebrain) noradrenergic neurons. Additionally, limited EtOH self-administration experience alters dialysate norepinephrine in the mPFC in a manner consistent with a decrease in tonic norepinephrine release. Further studies are necessary to elucidate the mechanisms by which EtOH exerts these variable effects.
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Affiliation(s)
- Saul Jaime
- From the, Division of Pharmacology and Toxicology (SJ, RAG), College of Pharmacy, The University of Texas at Austin, Austin, Texas
| | - Ashley A Vena
- From the, Division of Pharmacology and Toxicology (SJ, RAG), College of Pharmacy, The University of Texas at Austin, Austin, Texas.,Department of Psychiatry and Behavioral Neuroscience, University of Chicago, Chicago, Illinois
| | - Rueben A Gonzales
- Department of Psychiatry and Behavioral Neuroscience, University of Chicago, Chicago, Illinois
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12
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Daniulaityte R, Silverstein SM, Crawford TN, Martins SS, Zule W, Zaragoza AJ, Carlson RG. Methamphetamine Use and Its Correlates among Individuals with Opioid Use Disorder in a Midwestern U.S. City. Subst Use Misuse 2020; 55:1781-1789. [PMID: 32441178 PMCID: PMC7473491 DOI: 10.1080/10826084.2020.1765805] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Background: U.S. is experiencing a surging trend of methamphetamine use among individuals who use opioids. More research is needed to characterize this emerging "twin epidemic." Objectives: The study aims to identify social and behavioral characteristics associated with methamphetamine use among individuals with opioid use disorder (OUD) in the Dayton, Ohio, area, an epicenter of the opioid crisis and an emerging frontier of methamphetamine epidemic. Methods: 357 adult individuals with current OUD were recruited using targeted and respondent-driven sampling. Structured interviews collected information on social and drug use characteristics. Multivariable Logistic Regression was used to identify characteristics associated with the past 6-month use of methamphetamine. Results: 49.7% were female, and 88.8% were non-Hispanic whites. 55.6% used methamphetamine in the past 6-months, and 84.9% reported first use of methamphetamine after initiation of illicit opioids. Methamphetamine use was associated with homelessness (aOR = 2.46, p = .0001), lifetime history of diverted pharmaceutical stimulant use (aOR = 2.97, p < .001), injection route of heroin/fentanyl use (aOR = 1.89, p = .03), preference for fentanyl over heroin (aOR = 1.82, p = .048), lifetime history of extended-release injectable naltrexone (Vivitrol)-based treatment (aOR = 2.89, p = .003), and more frequent marijuana use (aOR = 1.26, p = .04). Discussion: The findings point to the complexity of motivational and behavioral pathways associated with methamphetamine and opioid co-use, ranging from self-treatment and substitution behaviors, attempts to endure homelessness, and greater risk taking to experience euphoria. More research is needed to understand the causal relationships and the association between methamphetamine and Vivitrol use. Public health responses to the opioid crisis need to be urgently expanded to address the growing epidemic of methamphetamine use.
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Affiliation(s)
| | - Sydney M Silverstein
- Center for Interventions, Treatment, and Addictions Research, Department of Population and Public Health Sciences, Boonshoft School of Medicine, Wright State University, Dayton, Ohio, USA
| | - Timothy N Crawford
- Department of Population and Public Health Sciences, Boonshoft School of Medicine, Wright State University, Dayton, Ohio, USA
| | - Silvia S Martins
- Department of Epidemiology, Columbia University Mailman School of Public Health, New York City, New York, USA
| | - William Zule
- Center for Global Health, International, Research Triangle Park, Durham, North Carolina, USA
| | - Angela J Zaragoza
- Center for Interventions, Treatment, and Addictions Research, Department of Population and Public Health Sciences, Boonshoft School of Medicine, Wright State University, Dayton, Ohio, USA
| | - Robert G Carlson
- Center for Interventions, Treatment, and Addictions Research, Department of Population and Public Health Sciences, Boonshoft School of Medicine, Wright State University, Dayton, Ohio, USA
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Abrahamsson CK, Nagarkar A, Fink MJ, Preston DJ, Ge S, Bozenko JS, Whitesides GM. Analysis of Powders Containing Illicit Drugs Using Magnetic Levitation. Angew Chem Int Ed Engl 2019. [DOI: 10.1002/ange.201910177] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
| | - Amit Nagarkar
- Department of Chemistry and Chemical Biology Harvard University USA
| | - Michael J. Fink
- Department of Chemistry and Chemical Biology Harvard University USA
| | | | - Shencheng Ge
- Department of Chemistry and Chemical Biology Harvard University USA
| | - Joseph S. Bozenko
- Special Testing and Research Laboratory Drug Enforcement Administration (DEA) Dulles VA USA
| | - George M. Whitesides
- Department of Chemistry and Chemical Biology Harvard University USA
- Wyss Institute for Biologically Inspired Engineering Harvard University 60 Oxford St. Cambridge MA 02138 USA
- Kavli Institute for Bionano Inspired Science and Technology Harvard University 29 Oxford Street Cambridge MA 02138 USA
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Abrahamsson CK, Nagarkar A, Fink MJ, Preston DJ, Ge S, Bozenko JS, Whitesides GM. Analysis of Powders Containing Illicit Drugs Using Magnetic Levitation. Angew Chem Int Ed Engl 2019; 59:874-881. [DOI: 10.1002/anie.201910177] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2019] [Indexed: 12/30/2022]
Affiliation(s)
| | - Amit Nagarkar
- Department of Chemistry and Chemical Biology Harvard University USA
| | - Michael J. Fink
- Department of Chemistry and Chemical Biology Harvard University USA
| | | | - Shencheng Ge
- Department of Chemistry and Chemical Biology Harvard University USA
| | - Joseph S. Bozenko
- Special Testing and Research Laboratory Drug Enforcement Administration (DEA) Dulles VA USA
| | - George M. Whitesides
- Department of Chemistry and Chemical Biology Harvard University USA
- Wyss Institute for Biologically Inspired Engineering Harvard University 60 Oxford St. Cambridge MA 02138 USA
- Kavli Institute for Bionano Inspired Science and Technology Harvard University 29 Oxford Street Cambridge MA 02138 USA
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Conditioned taste avoidance induced by the combination of heroin and cocaine: Implications for the use of speedball. Pharmacol Biochem Behav 2019; 187:172801. [PMID: 31678611 DOI: 10.1016/j.pbb.2019.172801] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/26/2019] [Revised: 10/09/2019] [Accepted: 10/10/2019] [Indexed: 11/30/2022]
Abstract
Speedball (heroin + cocaine) is a prevalent drug combination among intravenous drug users. Although its use is generally discussed to be a function of changes in the rewarding effects of either or both drugs, changes in the aversive effects of either drug may also be impacted (weakened) by the combination. To address this latter possibility and its potential role in the use of speedball, the present studies examined the interaction of cocaine and heroin in taste avoidance conditioning. In Experiment 1, male Sprague-Dawley rats were given access to a novel saccharin solution and then injected with either vehicle or heroin (3.2 mg/kg, IP) followed immediately by various doses of cocaine (10, 18 or 32 mg/kg, SC). At the two lowest doses of cocaine, only animals injected with the drug combination (H + C) displayed a taste avoidance relative to control subjects (taste avoidance was induced with both the combination and the high dose of cocaine). At no dose did animals injected with the combination of heroin and cocaine drink more than animals injected with cocaine alone. In Experiment 2, male Sprague-Dawley rats were similarly treated but injected with vehicle or cocaine (10 mg/kg) followed by injections of various doses of heroin (1.8, 3.2, 5.6 or 10 mg/kg). At the three highest doses of heroin, only animals injected with the drug combination (C + H) displayed significant avoidance relative to control subjects (no avoidance was evident with the combination of cocaine and the low dose of heroin). At no dose did animals injected with the combination of cocaine and heroin drink more than animals injected with heroin alone. Together, these results suggest that the aversive effects of heroin and cocaine are not attenuated by co-administration by cocaine and heroin, respectively. The importance of this for the use of speedball was discussed.
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Martins MJ, Roque Bravo R, Enea M, Carmo H, Carvalho F, Bastos MDL, Dinis-Oliveira RJ, Dias da Silva D. Ethanol addictively enhances the in vitro cardiotoxicity of cocaine through oxidative damage, energetic deregulation, and apoptosis. Arch Toxicol 2018; 92:2311-2325. [PMID: 29846769 DOI: 10.1007/s00204-018-2227-7] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2018] [Accepted: 05/17/2018] [Indexed: 11/30/2022]
Abstract
Cocaine (COC) is frequently consumed in polydrug abuse settings, and ethanol (EtOH) is the most prominent co-abused substance. Clinical data and experimental evidence suggest that the co-administration of COC with EtOH can be more cardiotoxic than EtOH or COC alone, but information on the molecular pathways involved is scarce. Since these data are crucial to potentiate the identification of therapeutic targets to treat intoxications, we sought to (i) elucidate the type of interaction that occurs between both substances, and (ii) assess the mechanisms implicated in the cardiotoxic effects elicited by COC combined with EtOH. For this purpose, H9c2 cardiomyocytes were exposed to COC (104 µM-6.5 mM) and EtOH (977 µM-4 M), individually or combined at a molar ratio based on blood concentrations of intoxicated abusers (COC 1: EtOH 9; 206 µM-110 mM). After 24 h, cell metabolic viability was recorded by the MTT assay and mixture toxicity expectations were calculated using the independent action (IA) and concentration addition (CA) models. EtOH (EC50 305.26 mM) proved to act additively with COC (EC50 2.60 mM) to significantly increase the drug in vitro cardiotoxicity, even when both substances were combined at individually non-cytotoxic concentrations. Experimental mixture testing (EC50 19.18 ± 3.36 mM) demonstrated that the cardiotoxicity was fairly similar to that predicted by IA (EC50 22.95 mM) and CA (EC50 21.75 mM), supporting additivity. Concentration-dependent increases of intracellular ROS/RNS and GSSG, depletion of GSH and ATP, along with mitochondrial hyperpolarization and activation of intrinsic, extrinsic, and common apoptosis pathways were observed both for single and combined exposures. In general, the mixture exhibited a toxicological profile that mechanistically did not deviate from the single drugs, suggesting that interventions such as antioxidant administration might aid in the clinical treatment of this type of polydrug intoxication. In a clinical perspective, the observed additive mixture effect may reflect the increased hazards at which users of this combination are exposed to in recreational settings.
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Affiliation(s)
- Maria João Martins
- UCIBIO/REQUIMTE, Laboratory of Toxicology, Biological Sciences Department, Faculty of Pharmacy, University of Porto, Rua Jorge Viterbo Ferreira, 228, Porto, 4050-313, Portugal
| | - Rita Roque Bravo
- UCIBIO/REQUIMTE, Laboratory of Toxicology, Biological Sciences Department, Faculty of Pharmacy, University of Porto, Rua Jorge Viterbo Ferreira, 228, Porto, 4050-313, Portugal
| | - Maria Enea
- UCIBIO/REQUIMTE, Laboratory of Toxicology, Biological Sciences Department, Faculty of Pharmacy, University of Porto, Rua Jorge Viterbo Ferreira, 228, Porto, 4050-313, Portugal
| | - Helena Carmo
- UCIBIO/REQUIMTE, Laboratory of Toxicology, Biological Sciences Department, Faculty of Pharmacy, University of Porto, Rua Jorge Viterbo Ferreira, 228, Porto, 4050-313, Portugal
| | - Félix Carvalho
- UCIBIO/REQUIMTE, Laboratory of Toxicology, Biological Sciences Department, Faculty of Pharmacy, University of Porto, Rua Jorge Viterbo Ferreira, 228, Porto, 4050-313, Portugal
| | - Maria de Lourdes Bastos
- UCIBIO/REQUIMTE, Laboratory of Toxicology, Biological Sciences Department, Faculty of Pharmacy, University of Porto, Rua Jorge Viterbo Ferreira, 228, Porto, 4050-313, Portugal
| | - Ricardo Jorge Dinis-Oliveira
- UCIBIO/REQUIMTE, Laboratory of Toxicology, Biological Sciences Department, Faculty of Pharmacy, University of Porto, Rua Jorge Viterbo Ferreira, 228, Porto, 4050-313, Portugal.,IINFACTS, Department of Sciences, Institute of Research and Advanced Training in Health Sciences and Technologies, University Institute of Health Sciences (IUCS-CESPU), Rua Central de Gandra, 1317, 4585-116, Gandra PRD, Portugal.,Department of Public Health, Forensic Sciences and Medical Education, Faculty of Medicine, University of Porto, Alameda Prof. Hernâni Monteiro, 4200-319, Porto, Portugal
| | - Diana Dias da Silva
- UCIBIO/REQUIMTE, Laboratory of Toxicology, Biological Sciences Department, Faculty of Pharmacy, University of Porto, Rua Jorge Viterbo Ferreira, 228, Porto, 4050-313, Portugal. .,IINFACTS, Department of Sciences, Institute of Research and Advanced Training in Health Sciences and Technologies, University Institute of Health Sciences (IUCS-CESPU), Rua Central de Gandra, 1317, 4585-116, Gandra PRD, Portugal.
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N-acetylaspartylglutamate Inhibits Heroin Self-Administration and Heroin-Seeking Behaviors Induced by Cue or Priming in Rats. Neurosci Bull 2017; 33:396-404. [PMID: 28534263 DOI: 10.1007/s12264-017-0140-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2016] [Accepted: 03/12/2017] [Indexed: 12/22/2022] Open
Abstract
Activation of presynaptic group II metabotropic glutamate receptors (mGluR2/3) inhibits drug reward and drug-seeking behavior, but the role of N-acetylaspartylglutamate (NAAG), an agonist of endogenous mGluR2/3, in heroin reward and heroin-seeking behavior remained unclear. Here, we aimed to explore the effects of exogenous NAAG on heroin self-administration and heroin-seeking behavior. First, rats were trained to self-administer heroin under a fixed ratio 1 (FR1) schedule for 10 days, then received NAAG (50 or 100 μg/10 μL in each nostril) in the absence or presence of LY341495 (1 mg/kg, i.p.), an antagonist of mGluR2/3, on day 11 and the effects of NAAG on heroin self-administration under FR1 were recorded for 3 consecutive days. Motivation was assessed in heroin self-administration under a progressive ratio schedule on day 11 in another 5 groups with the same doses of NAAG. Additional rats were withdrawn for 14 days after 14 days of heroin self-administration, then received the same pharmacological pretreatment and were tested for heroin-seeking behaviors induced by heroin priming or cues. The results showed that intranasal administration of NAAG significantly decreased intravenous heroin self-administration on day 12, but not on day 11. Pretreatment with LY341495 prior to testing on day 12 prevented the inhibitory effect of NAAG on heroin reinforcement. The break-point for reward motivation was significantly reduced by NAAG. Moreover, NAAG also significantly inhibited the heroin-seeking behaviors induced by heroin priming or cues and these were restored by pretreatment with LY341495. These results demonstrated that NAAG, via activation of presynaptic mGluR2/3, attenuated the heroin reinforcement, heroin motivational value, and heroin-seeking behavior, suggesting that it may be used as an adjunct treatment for heroin addiction.
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Drugs of abuse in drinking water – a review of current detection methods, occurrence, elimination and health risks. Trends Analyt Chem 2016. [DOI: 10.1016/j.trac.2016.09.011] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
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Vena AA, Mangieri R, Gonzales RA. Regional Analysis of the Pharmacological Effects of Acute Ethanol on Extracellular Striatal Dopamine Activity. Alcohol Clin Exp Res 2016; 40:2528-2536. [PMID: 27785807 PMCID: PMC5133149 DOI: 10.1111/acer.13246] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2015] [Accepted: 09/20/2016] [Indexed: 01/20/2023]
Abstract
BACKGROUND The objective of this study was to characterize the acute pharmacological effects of ethanol (EtOH) on extracellular dopamine in the dorsomedial and dorsolateral striata. This is the first study to quantify and directly compare the effects of acute EtOH on dopamine in these subregions. Therefore, we also tested the nucleus accumbens as a positive control. We hypothesized that while EtOH may increase extracellular dopamine in the dorsomedial striatum and dorsolateral striatum, the magnitude of this increase and the temporal profiles of extracellular dopamine concentrations would differ among the dorsomedial striatum, dorsolateral striatum, and nucleus accumbens. METHODS We performed in vivo microdialysis in adult, male Long Evans rats as they received a single (experiment 1) or repeated (experiment 2) doses of EtOH. RESULTS The results of our positive control study validate earlier work by our laboratory demonstrating that acute intravenous EtOH immediately and robustly increases extracellular dopamine in the nucleus accumbens (Howard et al., ). In contrast, a single 1-g/kg dose of intravenous EtOH did not significantly affect extracellular dopamine in the dorsomedial striatum or the dorsolateral striatum. However, following a cumulative EtOH dosing protocol, we observed a ramping up of tonic dopamine activity in both the dorsomedial striatum and dorsolateral striatum over the course of the experiment, but this effect was more robust in the dorsomedial striatum. CONCLUSIONS These results suggest that distinct mechanisms underlie the stimulating effects of acute EtOH on extracellular dopamine in striatal subregions. Additionally, our findings suggest a role for the dorsomedial striatum and minimal-to-no role for the dorsolateral striatum in mediating the intoxicating effects of acute moderate to high doses of EtOH.
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Affiliation(s)
- Ashley A Vena
- Division of Pharmacology and Toxicology, College of Pharmacy, University of Texas at Austin, Austin, Texas
| | - Regina Mangieri
- Division of Pharmacology and Toxicology, College of Pharmacy, University of Texas at Austin, Austin, Texas
| | - Rueben A Gonzales
- Division of Pharmacology and Toxicology, College of Pharmacy, University of Texas at Austin, Austin, Texas
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D'Souza MS. Glutamatergic transmission in drug reward: implications for drug addiction. Front Neurosci 2015; 9:404. [PMID: 26594139 PMCID: PMC4633516 DOI: 10.3389/fnins.2015.00404] [Citation(s) in RCA: 84] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2015] [Accepted: 10/12/2015] [Indexed: 12/12/2022] Open
Abstract
Individuals addicted to drugs of abuse such as alcohol, nicotine, cocaine, and heroin are a significant burden on healthcare systems all over the world. The positive reinforcing (rewarding) effects of the above mentioned drugs play a major role in the initiation and maintenance of the drug-taking habit. Thus, understanding the neurochemical mechanisms underlying the reinforcing effects of drugs of abuse is critical to reducing the burden of drug addiction in society. Over the last two decades, there has been an increasing focus on the role of the excitatory neurotransmitter glutamate in drug addiction. In this review, pharmacological and genetic evidence supporting the role of glutamate in mediating the rewarding effects of the above described drugs of abuse will be discussed. Further, the review will discuss the role of glutamate transmission in two complex heterogeneous brain regions, namely the nucleus accumbens (NAcc) and the ventral tegmental area (VTA), which mediate the rewarding effects of drugs of abuse. In addition, several medications approved by the Food and Drug Administration that act by blocking glutamate transmission will be discussed in the context of drug reward. Finally, this review will discuss future studies needed to address currently unanswered gaps in knowledge, which will further elucidate the role of glutamate in the rewarding effects of drugs of abuse.
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Affiliation(s)
- Manoranjan S D'Souza
- Pharmaceutical and Biomedical Sciences, Raabe College of Pharmacy, Ohio Northern University Ada, OH, USA
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Self-administration of cocaine and remifentanil by monkeys under concurrent-access conditions. Psychopharmacology (Berl) 2015; 232:321-30. [PMID: 24961564 PMCID: PMC4277508 DOI: 10.1007/s00213-014-3661-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/19/2013] [Accepted: 06/13/2014] [Indexed: 10/25/2022]
Abstract
RATIONALE Cocaine and opioids are often co-abused. Laboratory research has focused largely on the reinforcing effects of mixtures of drugs relative to the drugs alone. Less research has examined drug mixing by the subject under concurrent-access conditions. OBJECTIVE Self-administration of various doses of cocaine and remifentanil was examined under concurrent-access conditions. It was hypothesized that if cocaine and opioid combinations were more effective reinforcers than the single drugs, subjects would mix the two drugs by adjusting their responding to cocaine and an opioid alternative to maintain an optimal ratio of cocaine/remifentanil intake. METHOD Three male rhesus monkeys were allowed to self-administer cocaine (0.05-0.2 mg/kg/inj) or saline on one lever and remifentanil (0.05-0.4 μg/kg/inj) or saline on the other lever under concurrent fixed-ratio (FR) 10 schedules. Daily sessions lasted 2 h, and there was a 1-s timeout after every 10-s injection. RESULTS When saline and drug were concurrently available, responding on the saline-associated lever was low relative to the drug alternative. When cocaine and remifentanil were concurrently available, both drugs were self-administered above saline levels. Cocaine intake decreased, and remifentanil intake increased as a function of the remifentanil dose that was available. Conversely, cocaine intake and remifentanil intake did not change systematically as a function of the cocaine dose that was available. CONCLUSION Monkeys will mix cocaine and an opioid when the two drugs are available concurrently. However, there was no indication that monkeys titrated drug intake to maintain an optimal ratio of intake of the two compounds.
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The phosphodiesterase-4 inhibitor rolipram attenuates heroin-seeking behavior induced by cues or heroin priming in rats. Int J Neuropsychopharmacol 2014; 17:1397-407. [PMID: 24832929 DOI: 10.1017/s1461145714000595] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Inhibition of phosphodiesterase-4 (PDE4), an enzyme that specifically hydrolyzes cyclic adenosine monophosphate (cAMP) increases intracellular cAMP/cAMP-response element binding protein (CREB) signaling. Activation of this signaling is considered as an important compensatory response that decreases motivational properties of drugs of abuse. However, it is not known whether PDE4 is involved in heroin seeking. Self-administration of heroin (50 μg/kg/infusion) was performed under the fixed ratio 1 (FR1) schedule for 14 d and then drug seeking was extinguished for 10 d. The progressive ratio schedule was used to evaluate the relative motivational value of heroin reinforcement. After training, the conditioned cue or heroin priming (250 μg/kg) was introduced for the reinstatement of heroin-seeking behavior. Pretreatment (i.p.) with rolipram (0.03-0.3 mg/kg), a prototypical, selective PDE4 inhibitor, failed to inhibit heroin self-administration under the FR1 schedule, but decreased the reward values under the progressive ratio schedule in a dose-dependent manner. In addition, rolipram decreased the reinstatement of heroin seeking induced by cues or heroin priming even at the lowest dose (0.03 mg/kg); in contrast, the highest dose (0.3 mg/kg) of rolipram was required to decrease sucrose reinforcement. Finally, the effects of rolipram on heroin-seeking behavior were correlated with the increases in expression of phosphorylated CREB in the nucleus accumbens. The study demonstrated that rolipram inhibited heroin reward and heroin-seeking behavior. The results suggest that PDE4 plays an essential role in mediating heroin seeking and that PDE4 inhibitors may be used as a potential pharmacotherapeutic approach for heroin addiction.
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Exercise decreases speedball self-administration. Life Sci 2014; 114:86-92. [PMID: 25132360 DOI: 10.1016/j.lfs.2014.08.005] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2014] [Revised: 08/01/2014] [Accepted: 08/05/2014] [Indexed: 01/01/2023]
Abstract
AIMS Epidemiological studies report that individuals who exercise are less likely to abuse drugs. Preclinical studies report that exercise, in the form of treadmill or wheel running, reliably decreases the self-administration of psychomotor stimulants and opioids. To date, preclinical studies have only examined the effects of exercise on responding maintained by individual drugs and not by combinations of multiple drugs. This limits the translational appeal of these studies because polydrug abuse is common among substance abusing populations. The purpose of this study was to examine the effects of exercise on the self-administration of speedball, a combination of cocaine and heroin that is frequently encountered in intravenous drug abusing populations. MAIN METHODS Female rats were obtained at weaning and assigned to sedentary or exercising conditions. Sedentary rats were housed in standard cages that permitted no exercise beyond normal cage ambulation; exercising rats were housed in similar cages with an activity wheel. After 6weeks, rats were implanted with intravenous catheters and trained to self-administer cocaine, heroin, and dose combinations of cocaine and heroin (i.e., speedball) on a progressive ratio schedule of reinforcement. KEY FINDINGS Doses of speedball maintained greater levels of responding than corresponding doses of cocaine and heroin alone. Importantly, responding maintained by cocaine, heroin, and speedball was lower in exercising rats than sedentary rats. SIGNIFICANCE These data indicate that exercise decreases the self-administration of speedball and suggest that exercise may reduce the abuse of drug combinations that have traditionally been resistant to treatment.
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Schier CJ, Dilly GA, Gonzales RA. Intravenous ethanol increases extracellular dopamine in the medial prefrontal cortex of the Long-Evans rat. Alcohol Clin Exp Res 2013; 37:740-7. [PMID: 23421849 DOI: 10.1111/acer.12042] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2012] [Accepted: 08/28/2012] [Indexed: 11/30/2022]
Abstract
BACKGROUND Ethanol (EtOH) affects prefrontal cortex functional roles such as decision making, working memory, and behavioral control. Yet, the pharmacological effect of EtOH on dopamine, a neuromodulator in the medial prefrontal cortex (mPFC), is unclear. Past studies exploring this topic produced conflicting outcomes; however, a handful of factors (temporal resolution, method of drug administration, estrous cycle) possibly contributed to these discrepancies. We sought to mitigate these factors in order to elucidate EtOH's pharmacological effects on mPFC dopamine in Long-Evans rats. METHODS We administered experimental solutions via an intravenous (iv), handling-free route, monitored dopamine in the mPFC via microdialysis (10-minute samples), and used male rats to avoid estrous cycle/EtOH interactions. First, we rapidly (approximately 2.7 ml/min) or slowly (approximately 0.6 ml/min) administered 1.0 g/kg EtOH and saline infusions, showing that the experimental methods did not contribute to dopamine changes. Then, a cumulative dosing protocol was used to administer 0.25, 0.75, 1.50, and 2.25 g/kg iv EtOH doses to evaluate dose-response. Finally, we monitored dialysate EtOH levels during an oral EtOH self-administration session to compare the dialysate EtOH levels achieved during the pharmacological experiments to those seen during self-administration. RESULTS IV administration of a rapid or slow 1.0 g/kg EtOH infusion resulted in similar significant 55 ± 9 and 63 ± 15% peak dialysate dopamine increases, respectively. The 0.25, 0.75, 1.50, and 2.25 g/kg EtOH doses produced a nonsignificant 17 ± 5% and significant 36 ± 15, 68 ± 19, and 86 ± 20% peak dialysate dopamine increases, respectively. Self-administration dialysate EtOH concentrations fell within the range of concentrations noted during the EtOH dose-response curve. CONCLUSIONS These experiments show that, using experimental methods that minimize possibly confounding factors, acute iv EtOH increases extracellular dopamine in the mPFC in a dose-dependent manner, thereby clarifying EtOH's pharmacological effects on the mesocortical dopamine system.
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Affiliation(s)
- Christina J Schier
- College of Pharmacy, The University of Texas at Austin, Austin, TX 78712, USA
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Self-administration of cocaine and remifentanil by monkeys: choice between single drugs and mixtures. Psychopharmacology (Berl) 2011; 215:281-90. [PMID: 21191570 PMCID: PMC3107981 DOI: 10.1007/s00213-010-2131-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/27/2010] [Accepted: 12/01/2010] [Indexed: 10/18/2022]
Abstract
RATIONALE Cocaine and opioids are often co-abused. As yet, however, there is no clear evidence that the drugs interact to make the mixture a more effective reinforcer. OBJECTIVE The present study examined the relative reinforcing potency and maximum effectiveness of the cocaine-opioid combination in monkeys given a choice between cocaine-opioid mixtures and the single-component drugs. METHOD Rhesus monkeys were allowed to choose between injections of cocaine (100 μg/kg/inj) and other doses of cocaine (10-560 μg/kg/inj) or remifentanil (0.03-3.0 μg/kg/inj). A dose-addition model was used to select dose combinations for mixtures of cocaine and remifentanil predicted to be equivalent to 100 μg/kg/inj of cocaine in reinforcing effect if the drugs were additive. The monkeys were then allowed to choose between (a) cocaine and mixtures predicted to be equivalent to 100 μg/kg/inj of cocaine, (b) increasing doses of the mixtures and the single-component drugs, and (c) cocaine or remifentanil at doses that were in the highest safe range. RESULTS Generally, monkeys preferred the mixtures over 100 μg/kg/inj of cocaine, evidence for superadditivity. However, preferences for the mixture ceased when relatively high doses of single-component drugs were offered as alternatives. When doses within the mixture were raised and offered with relatively high doses of the single drugs, there was no clear preference for either option. The highest dose of remifentanil was chosen over the highest dose of cocaine by all monkeys. CONCLUSION The current results indicate that cocaine-opioid combinations can be super-additive in terms of potency, but are not, at maximum, more effective than the single-component drugs.
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Social defeat stress in rats: escalation of cocaine and "speedball" binge self-administration, but not heroin. Psychopharmacology (Berl) 2011; 215:165-75. [PMID: 21197616 PMCID: PMC3707112 DOI: 10.1007/s00213-010-2139-6] [Citation(s) in RCA: 89] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/17/2010] [Accepted: 11/29/2010] [Indexed: 01/09/2023]
Abstract
RATIONALE Exposure to intermittent episodes of social defeat stress can increase drug seeking and leads to intense drug taking in rats. OBJECTIVES This study investigated the consequences of repeated, intermittent social defeat stress on patterns of drug self-administration in rats with access to heroin, cocaine, or a heroin-cocaine combination ("speedball"). METHODS Male Long-Evans rats were either handled (controls) or subjected to 25-min social defeat stress episodes on days 1, 4, 7, and 10 during confrontations with an aggressive resident. Ten days following the last defeat, rats were assessed for locomotor cross-sensitization in response to heroin or cocaine. Animals were then prepared with intrajugular catheters for drug self-administration. Separate groups of controls and defeated rats were examined for self-administration of heroin (experiment 1), a heroin-cocaine combination (experiment 2), or cocaine (experiment 3). Drug self-administration patterns were evaluated using fixed or progressive ratio schedules of reinforcement during limited access sessions or a 24-h unlimited access binge. RESULTS Rats with a history of intermittent social defeat stress showed sensitized locomotor behavior when challenged with heroin or cocaine relative to controls. During the 24-h binge session, defeated rats escalated cocaine-taking behavior (ca. 110 mg/kg vs. 66 mg/kg in controls), persisted in self-administering cocaine or the heroin-cocaine mixture for more hours, and showed a tendency for increased heroin-cocaine intake, but no effects on heroin taking. CONCLUSIONS A history of social defeat stress seems to preferentially promote escalated intake of cocaine but not heroin, unless a heroin-cocaine combination is available.
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Powerful behavioral interactions between methamphetamine and morphine. Pharmacol Biochem Behav 2011; 99:451-8. [PMID: 21549146 DOI: 10.1016/j.pbb.2011.04.014] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/02/2011] [Revised: 04/06/2011] [Accepted: 04/16/2011] [Indexed: 11/20/2022]
Abstract
Use of drugs of abuse in combination is common among recreational users and addicts. The combination of a psychomotor stimulant with an opiate, known as a 'speedball,' reportedly produces greater effects than either drug alone and has been responsible for numerous deaths. Historically, the most popular speedball combination is that of cocaine and heroin. However, with the growing popularity of methamphetamine in recent years, there has been increased use of this drug in combination with other drugs of abuse, including opiates. Despite this, relatively little research has examined interactions between methamphetamine and opiates. In the current research, behavioral interactions between methamphetamine and the prototypical opiate, morphine, were examined across a variety of dose combinations in Sprague-Dawley rats. The combination of methamphetamine and morphine produced stimulation of behavior that was dramatically higher than either drug alone; however, the magnitude of the interaction was dependent on the dose of the drugs and the specific behaviors examined. The results demonstrate complex behavioral interactions between these drugs, but are consistent with the idea that this combination is used because it produces a greater effect than either drug alone.
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Greenwald MK, Lundahl LH, Steinmiller CL. Sustained release d-amphetamine reduces cocaine but not 'speedball'-seeking in buprenorphine-maintained volunteers: a test of dual-agonist pharmacotherapy for cocaine/heroin polydrug abusers. Neuropsychopharmacology 2010; 35:2624-37. [PMID: 20881947 PMCID: PMC2978797 DOI: 10.1038/npp.2010.175] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The aim of this study was to determine whether oral sustained release d-amphetamine (SR-AMP) reduces cocaine and opioid/cocaine combination ('speedball'-like) seeking in volunteers with current opioid dependence and cocaine dependence. Following outpatient buprenorphine (BUP) 8 mg/day stabilization without SR-AMP, eight participants completed a 3-week in-patient study with continued BUP 8 mg/day maintenance and double-blind ascending SR-AMP weekly doses of 0, 30, and 60 mg/day, respectively. After 3 days (Saturday-Monday) stabilization at each SR-AMP weekly dose (0, 15, or 30 mg administered at 0700 and 1225 each day), on Tuesday-Friday mornings (0900-1200 hours), participants sampled four drug combinations in randomized, counterbalanced order under double-blind, double-dummy (intranasal cocaine and intramuscular hydromorphone) conditions: cocaine (COC 100 mg+saline); hydromorphone (COC 4 mg+HYD 24 mg); 'speedball' (COC 100 mg+HYD 24 mg); and placebo (COC 4 mg+saline). Subjective and physiological effects of these drug combinations were measured. From 1230 to 1530 hours, participants could respond on a choice, 12-trial progressive ratio schedule to earn drug units (1/12th of total morning dose) or money units (US$2). SR-AMP significantly reduced COC, but not HYD or speedball, choices and breakpoints. SR-AMP also significantly reduced COC subjective (eg, abuse-related) effects and did not potentiate COC-induced cardiovascular responses. This study shows the ability of SR-AMP to attenuate COC self-administration, as well as its selectivity, in cocaine/heroin polydrug abusers. Further research is warranted to ascertain whether SR-AMP combined with BUP could be a useful dual-agonist pharmacotherapy.
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Affiliation(s)
- Mark K Greenwald
- Substance Abuse Research Division, Department of Psychiatry and Behavioral Neurosciences, Wayne State University School of Medicine, Detroit, MI 48207, USA.
| | - Leslie H Lundahl
- Substance Abuse Research Division, Department of Psychiatry and Behavioral Neurosciences, Wayne State University School of Medicine, Detroit, MI, USA
| | - Caren L Steinmiller
- Substance Abuse Research Division, Department of Psychiatry and Behavioral Neurosciences, Wayne State University School of Medicine, Detroit, MI, USA,Department of Pharmacology and Toxicology, University of Toledo, Toledo, OH, USA
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Wang X, Pang J, Maffucci JA, Pade DS, Newman RA, Kerwin SM, Bowman PD, Stavchansky S. Pharmacokinetics of caffeic acid phenethyl ester and its catechol-ring fluorinated derivative following intravenous administration to rats. Biopharm Drug Dispos 2009; 30:221-8. [DOI: 10.1002/bdd.657] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Woolverton WL, Wang Z, Vasterling T, Tallarida R. Self-administration of cocaine-remifentanil mixtures by monkeys: an isobolographic analysis. Psychopharmacology (Berl) 2008; 198:387-94. [PMID: 18461311 PMCID: PMC2667245 DOI: 10.1007/s00213-008-1152-5] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/21/2007] [Accepted: 03/24/2008] [Indexed: 10/22/2022]
Abstract
RATIONALE Abuse of mixtures of stimulants and opioids ("speedball") is common. Although this combination has been studied in the laboratory, conclusions about the nature of the cocaine/opioid interaction have been mixed. OBJECTIVES The objectives of the present experiment were to allow monkeys to self-administer mixtures of cocaine and the mu opioid agonist remifentanil and to quantify the interaction using the isobolographic approach. Our hypothesis was that the drugs would be super-additive in their reinforcing effects. MATERIALS AND METHODS Rhesus monkeys (n = 5) prepared with i.v. catheters were allowed to self-administer cocaine or saline under a progressive-ratio schedule. When responding was stable, doses of cocaine or remifentanil were made available in test sessions. Next, mixtures of doses of the drugs were tested over a range of doses in 1:1, 1:2, and 2:1 ratios of their ED(50)s. Results were analyzed using isobolographic techniques. RESULTS Both drugs alone and all drug mixtures functioned as positive reinforcers in a dose-related manner. Cocaine maintained more responding at maximum than did remifentanil, i.e., was a stronger reinforcer. The experimentally determined equi-effective dose for the 1:1 and 1:2 cocaine/remifentanil mixtures tended toward super-additivity, but the difference from additivity did not achieve statistical significance. The 2:1 mixture was super-additive. Maximum responding maintained by the mixtures was higher than that maintained by remifentanil but not different from cocaine. CONCLUSIONS Combinations of cocaine and remifentanil can be additive or super-additive as positive reinforcers, depending on proportions of each. Interactions between stimulants and opioids may contribute to the abuse of these mixtures.
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Affiliation(s)
- W. L. Woolverton
- Division of Neurobiology and Behavior Research, Department of Psychiatry and Human Behavior, University of Mississippi Medical Center, 2500 N. State Street, Jackson, MS 39216, USA, ,Department of Psychiatry, University of Mississippi Medical Center, Jackson, MS 39216, USA
| | - Zhixia Wang
- Division of Neurobiology and Behavior Research, Department of Psychiatry and Human Behavior, University of Mississippi Medical Center, 2500 N. State Street, Jackson, MS 39216, USA,Department of Psychiatry, University of Mississippi Medical Center, Jackson, MS 39216, USA
| | - Theresa Vasterling
- Division of Neurobiology and Behavior Research, Department of Psychiatry and Human Behavior, University of Mississippi Medical Center, 2500 N. State Street, Jackson, MS 39216, USA,Department of Psychiatry, University of Mississippi Medical Center, Jackson, MS 39216, USA
| | - Ronald Tallarida
- Department of Pharmacology, Temple University School of Medicine, Philadelphia, PA 19140, USA,Department of Psychiatry, University of Mississippi Medical Center, Jackson, MS 39216, USA
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Howard EC, Schier CJ, Wetzel JS, Duvauchelle CL, Gonzales RA. The shell of the nucleus accumbens has a higher dopamine response compared with the core after non-contingent intravenous ethanol administration. Neuroscience 2008; 154:1042-53. [PMID: 18511209 DOI: 10.1016/j.neuroscience.2008.04.014] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2007] [Revised: 03/26/2008] [Accepted: 04/14/2008] [Indexed: 11/29/2022]
Abstract
Dopamine increases in the nucleus accumbens after ethanol administration in rats, but the contributions of the core and shell subregions to this response are unclear. The goal of this study was to determine the effect of various doses of i.v. ethanol infusions on dopamine in these two subregions of the nucleus accumbens. Male Long-Evans rats were infused with either acute i.v. ethanol (0.5, 1.0, 1.5 g/kg), repeated i.v. ethanol (four 1.0 g/kg infusions resulting in a cumulative dose of 4.0 g/kg), or saline as a control for each condition. Dopamine and ethanol were measured in dialysate samples from each experiment. The in vivo extraction fraction for ethanol of probes was determined using i.v. 4-methylpyrazole, and was used to estimate peak brain ethanol concentrations after the infusions. The peak brain ethanol concentrations after the 0.5, 1.0 and 1.5 g/kg ethanol infusions were estimated to be 20, 49 and 57 mM, respectively. A significant dopamine increase was observed for the 0.5 g/kg ethanol group when collapsed across subregions. However, both the 1.0 g/kg and 1.5 g/kg ethanol infusions produced significant increases in dopamine levels in the shell that were significantly higher than those in the core. An ethanol dose-response effect on dopamine in the shell was observed when saline controls, 0.5, 1.0, and 1.5 g/kg groups were compared. For the cumulative-dosing study, the first, second, and fourth infusions resulted in significant increases in dopamine in the shell. However, these responses were not significantly different from one another. The results of this study show that the shell has a stronger response than the core to i.v. ethanol, that dopamine in the shell increases in a dose-dependent manner between 0.5-1.0 g/kg doses, but that the response to higher ethanol doses reaches a plateau.
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Affiliation(s)
- E C Howard
- College of Pharmacy, Department of Pharmacology, The University of Texas at Austin, 1 University Station A1915, Austin, TX 78712, USA
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Self-administration of drug mixtures by monkeys: combining drugs with comparable mechanisms of action. Psychopharmacology (Berl) 2008; 196:575-82. [PMID: 18026937 PMCID: PMC3109501 DOI: 10.1007/s00213-007-0991-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/09/2007] [Accepted: 10/16/2007] [Indexed: 10/22/2022]
Abstract
RATIONALE Abuse of drug mixtures is common. Drug interactions that are super-additive in terms of reinforcing effects may contribute to this phenomenon. Although quantitative methods for assessing drug interactions have been developed, they have not been widely applied to the analysis of reinforcing effects. OBJECTIVES The present experiment was designed to study self-administration of mixtures of drugs with comparable pharmacological mechanisms of action. Our hypothesis was that the drugs would be dose-additive. MATERIALS AND METHODS Rhesus monkeys prepared with i.v. catheters were allowed to self-administer cocaine or saline under a progressive-ratio schedule in baseline sessions. When responding was stable, two mu opioid agonists, alfentanil and remifentanil, were tested alone in one group (n = 5). Two dopamine (DA) uptake blockers, cocaine and RTI-117 were tested in the other group (n = 6). Next, mixtures of doses of the two opioids or the two DA uptake blockers were tested in approximate 1:1, 1:2, and 2:1 ratios of their ED50s. Results were analyzed using isobolographic techniques. RESULTS All drugs alone and drug mixtures functioned as positive reinforcers in a dose-related manner. There was no difference between experimentally determined ED50 values and predicted additive ED50 values for any mixture. Maximum responding maintained by mixtures, a measure of reinforcing strength, did not differ from that for single drugs. CONCLUSIONS Mixtures of various proportions of two drugs with comparable mechanisms of action were additive, i.e., they did not interact. This result will serve as the basis for comparison to studies of mixtures of drugs with various mechanisms of action.
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Rocha A, Valles R, Hart N, Bratton GR, Nation JR. Developmental lead exposure attenuates methamphetamine dose-effect self-administration performance and progressive ratio responding in the male rat. Pharmacol Biochem Behav 2008; 89:508-14. [PMID: 18329702 DOI: 10.1016/j.pbb.2008.02.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/20/2007] [Revised: 01/17/2008] [Accepted: 02/02/2008] [Indexed: 10/22/2022]
Abstract
Perinatal (gestation/lactation) lead exposure modifies the reinforcement efficacy of various psychoactive drugs (e.g., cocaine, opiates) across the phases of initial selection, use, and abuse [Nation J.R., Cardon A.L., Heard H.M., Valles R., Bratton G.R. Perinatal lead exposure and relapse to drug-seeking behavior in the rat: a cocaine reinstatement study. Psychopharmacol 2003;168: 236-243.; Nation J.R., Smith K.R., Bratton G.R. Early developmental lead exposure increases sensitivity to cocaine in a self-administration paradigm. Pharmacol Biochem Behave 2004; 77: 127-13; Rocha A., Valles R., Cardon A.L., Bratton G.R., Nation J.R. Enhanced acquisition of cocaine self-administration in rats developmentally exposed to lead. Neuropsychopharmacol 2005; 30: 2058-2064.]. However, changes in sensitivity to methamphetamine across the phases of drug abuse have not been examined in animals perinatally exposed to lead. Because the mainstream popularity of methamphetamine in the United States is increasing and lead exposure continues to be widespread, an examination of this drug and how it may be modified by perinatal exposure to lead is warranted. The studies reported here examined the effects of perinatal lead exposure on adult self-administration of intravenous (i.v.) methamphetamine across the maintenance phase of drug addiction. Experiment 1 examined dose-effect patterns in control and lead-exposed animals. Experiment 2 evaluated control and lead-exposed animals in a progressive ratio task. Female rats were administered a 16-mg lead or a control solution for 30 days prior to breeding with non-exposed males. Exposure continued through pregnancy and lactation and was discontinued at weaning (postnatal day [PND] 21). Animals born to control or lead-exposed dams received indwelling jugular catheters as adults (PND 70) and subsequently were randomly assigned to one of the two studies, using only one male rat per litter for each study. The data showed a general attenuation of the reinforcement efficacy of methamphetamine in animals perinatally exposed to lead, as compared to control animals.
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Affiliation(s)
- Angelica Rocha
- Department of Psychology, Texas A&M University, College Station, TX 77843, United States
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Cornish JL, Clemens KJ, Thompson MR, Callaghan PD, Dawson B, McGregor IS. High ambient temperature increases intravenous methamphetamine self-administration on fixed and progressive ratio schedules in rats. J Psychopharmacol 2008; 22:100-10. [PMID: 18187537 DOI: 10.1177/0269881107082286] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Methamphetamine is a drug that is often consumed at dance parties or nightclubs where the ambient temperature is high. The present study determined whether such high ambient temperatures alter intravenous methamphetamine self-administration in the rat. Male Hooded Wistar rats were trained to self-administer intravenous methamphetamine (0.1 mg/kg/infusion) under a fixed ratio 1 (FR1) or progressive ratio (PR) schedule of reinforcement at an ambient temperature of 23 +/- 1 degrees C. They were then given their daily self-administration session at a raised ambient temperature of 30 +/- 1 degrees C. Methamphetamine self-administration was increased at 30 degrees C under both FR1 and PR reinforcement schedules, with the latter effect indicating that heat enhances the motivation to obtain methamphetamine. High temperatures did not alter self-administration of the D1 receptor agonist SKF 82958 in methamphetamine-experienced rats suggesting some specificity in the methamphetamine effect. When rats were given access to drink isotonic saline solution during methamphetamine self-administration sessions they drank much more solution at 30 degrees C than 23 degrees C. However, availability of isotonic saline to drink did not alter the heat-induced facilitation of methamphetamine self-administration (PR schedule) indicating that the heat effect does not simply reflect increased motivation for intravenous fluids. Hyperthermia was evident in rats self-administering methamphetamine at high ambient temperatures and fluid consumption did not prevent this effect. Heat did not affect blood levels of methamphetamine, or its principal metabolite amphetamine indicating that the facilitatory effect of heat did not reflect altered methamphetamine pharmacokinetics. Overall, these results show that high ambient temperatures increase the reinforcing efficacy of methamphetamine and encourage higher levels of drug intake.
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Affiliation(s)
- Jennifer L Cornish
- Neuropharmacology Laboratory, Department of Psychology, Macquarie University, Sydney, Australia.
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Maffucci JA, Walker DM, Ikegami A, Woller MJ, Gore AC. NMDA receptor subunit NR2b: effects on LH release and GnRH gene expression in young and middle-aged female rats, with modulation by estradiol. Neuroendocrinology 2008; 87:129-41. [PMID: 18025808 PMCID: PMC2671961 DOI: 10.1159/000111136] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/27/2007] [Accepted: 10/09/2007] [Indexed: 11/19/2022]
Abstract
BACKGROUND/AIMS The loss of reproductive capacity during aging involves changes in the neural regulation of the hypothalamic gonadotropin-releasing hormone (GnRH) neurons controlling reproduction. This neuronal circuitry includes glutamate receptors on GnRH neurons. Previously, we reported an increase in the expression of the NR2b subunit protein of the NMDA receptor on GnRH neurons in middle-aged compared to young female rats. Here, we examined the functional implications of the NR2b subunit on the onset of reproductive aging, using an NR2b-specific antagonist ifenprodil. METHODS Young (3-5 months) and middle-aged (10-13 months) female rats were ovariectomized (OVX), 17beta-estradiol (E2) or vehicle (cholesterol) treated, and implanted with a jugular catheter. Serial blood sampling was undertaken every 10 min for 4 h, with ifenprodil (10 mg/kg) or vehicle injected (i.p.) after 1 h of baseline sampling. The pulsatile release of pituitary LH and levels of GnRH mRNA in hypothalamus were quantified as indices of the reproductive axis. RESULTS Our results showed effects of ifenprodil on both endpoints. In OVX rats given cholesterol, neither age nor ifenprodil had any effects on LH release. In E2-treated rats, aging was associated with significant decreases in pulsatile LH release. Additionally, ifenprodil stimulated parameters of pulsatile LH release in both young and middle-aged animals. Ifenprodil had few effects on GnRH mRNA; the only significant effect of ifenprodil was found in the middle-aged, cholesterol group. CONCLUSION Together, these findings support a role for the NR2b subunit of the NMDAR in GnRH/LH regulation. Because most of these effects were exhibited on pituitary LH release in the absence of a concomitant change in GnRH gene expression, it is likely that NMDA receptors containing the NR2b subunit play a role in GnRH-induced LH release, independent of de novo GnRH gene expression.
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Affiliation(s)
| | - Deena M. Walker
- Institute for Neuroscience, University of Texas, Austin, TX 78712
| | - Aiko Ikegami
- Division of Pharmacology & Toxicology, University of Texas, Austin, TX 78712
| | - Michael J. Woller
- Biological Sciences, University of Wisconsin-Whitewater, Whitewater, WI 53190
| | - Andrea C. Gore
- Institute for Neuroscience, University of Texas, Austin, TX 78712
- Division of Pharmacology & Toxicology, University of Texas, Austin, TX 78712
- Institute for Cellular & Molecular Biology, University of Texas, Austin, TX 78712
- Correspondence: Dr. Andrea C. Gore, Division of Pharmacology and Toxicology, The University of Texas at Austin, 1 University Station A1915, Austin, TX 78712, USA, Phone: 512-471-3669, Fax: 512-471-5002,
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Wade-Galuska T, Winger G, Woods JH. A behavioral economic analysis of cocaine and remifentanil self-administration in rhesus monkeys. Psychopharmacology (Berl) 2007; 194:563-72. [PMID: 17628791 DOI: 10.1007/s00213-007-0858-0] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/22/2007] [Accepted: 06/11/2007] [Indexed: 10/23/2022]
Abstract
RATIONALE Behavioral economics can be used to evaluate the relative reinforcing effectiveness of drugs and the economic interaction between drugs, information which may help to explain patterns of polydrug abuse in humans. OBJECTIVES In phase 1, the reinforcing effectiveness of the opiate remifentanil and the stimulant cocaine was compared using a demand-curve analysis. In phase 2, the economic relation between these drugs was determined. MATERIALS AND METHODS Rhesus monkeys pressed levers according to fixed-ratio schedules for intravenous drug infusions. A demand-curve analysis was conducted (phase 1) in which drug consumption was measured as the response requirement, or price, was increased, and the rate at which consumption decreased with increases in price (demand elasticity) provided an index of the reinforcing effectiveness of each drug. Cocaine and remifentanil were then available concurrently (phase 2), and the price of one drug was increased (the manipulated-price alternative) while the price of the other drug was held constant (the fixed-price alternative). Consumption of the fixed-price alternative was measured as a function of increases in the price of the manipulated-price alternative, and demand for the manipulated-price alternative was assessed. RESULTS The reinforcing effectiveness of cocaine and remifentanil did not significantly differ, and these drugs functioned as economic substitutes. As the price of the manipulated-price alternative increased, consumption of the fixed-price alternative increased. In addition, demand for the manipulated-price alternative became more elastic with the concurrent availability of the fixed-price alternative. CONCLUSION Polydrug use involving stimulants and opiates may occur because these drugs are highly substitutable.
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Affiliation(s)
- Tammy Wade-Galuska
- Department of Pharmacology, University of Michigan, Ann Arbor, MI 48109-0632, USA.
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Mello NK, Negus SS. Effects of d-amphetamine and buprenorphine combinations on speedball (cocaine+heroin) self-administration by rhesus monkeys. Neuropsychopharmacology 2007; 32:1985-94. [PMID: 17228335 DOI: 10.1038/sj.npp.1301319] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The simultaneous i.v. administration of heroin and cocaine, called a 'speedball,' is often reported clinically, and identification of effective pharmacotherapies is a continuing challenge. We hypothesized that treatment with combinations of a monoamine releaser d-amphetamine, and a mu partial agonist, buprenorphine, might reduce speedball self-administration by rhesus monkeys. Speedballs (0.01 mg/kg/inj cocaine+0.0032 mg/kg/inj heroin) and food (1 g banana-flavored pellets) were available during four daily sessions on a second-order schedule of reinforcement (fixed ratio (FR)2 (variable ratio (VR)16:S)). Monkeys were treated for 10 days with saline or ascending doses of d-amphetamine (0.0032-0.032 mg/kg/h)+buprenorphine (0.075 or 0.237 mg/kg/day) in combination. d-Amphetamine+both doses of buprenorphine produced an amphetamine dose-dependent decrease in speedball self-administration in comparison to the saline treatment baseline (P<0.01-0.001), but food-maintained responding did not change significantly. d-Amphetamine alone (0.032 mg/kg/h) significantly decreased both food (P<0.01) and speedball-maintained responding (P<0.05). During saline control treatment, speedball unit doses of 0.0032 mg/kg/inj cocaine+0.001 mg/kg/inj heroin were at the peak of the speedball dose-effect curve. Daily treatment with 0.01 mg/kg/h d-amphetamine+0.237 mg/kg/day buprenorphine produced a significant downward and rightward shift in the speedball dose-effect curve (P<0.01) and no significant effect on food-maintained responding. A significant decrease in speedball self-administration was sustained over 10 days of treatment. These findings are consistent with our previous reports and suggest that medication mixtures designed to target both the stimulant and the opioid component of the speedball may be an effective approach to polydrug abuse treatment.
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Affiliation(s)
- Nancy K Mello
- Alcohol and Drug Abuse Research Center, Harvard Medical School-McLean Hospital, 115 Mill Street, Belmont, MA 02478, USA.
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Garrido JMPJ, Marques MPM, Silva AMS, Macedo TRA, Oliveira-Brett AM, Borges F. Spectroscopic and electrochemical studies of cocaine–opioid interactions. Anal Bioanal Chem 2007; 388:1799-808. [PMID: 17604984 DOI: 10.1007/s00216-007-1375-z] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2007] [Revised: 05/15/2007] [Accepted: 05/23/2007] [Indexed: 10/23/2022]
Abstract
The drugs of abuse cocaine (C), heroin (H), and morphine (M) have been studied to enable understanding of the occurrence of cocaine-opioid interactions at a molecular level. Electrochemical, Raman, and NMR studies of the free drugs and their mixtures were used to study drug-drug interactions. The results were analyzed using data obtained from quantum-mechanical calculations. For the cocaine-morphine mixture (C-MH), formation of a binary complex was detected; this involved the 3-phenolic group and the heterocyclic oxygen of morphine and the carbonyl oxygen and the methyl protons of cocaine's methyl ester group. NMR studies conducted simultaneously also revealed C-MH binding geometry consistent with theoretical predictions and with electrochemical and vibrational spectroscopy results. These results provide evidence for the occurrence of a cocaine-morphine interaction, both in the solid state and in solution, particularly for the hydrochloride form. A slight interaction, in solution, was also detected by NMR for the cocaine-heroin mixture.
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Affiliation(s)
- Jorge M P J Garrido
- Unidade I&D Química-Física Molecular, Universidade de Coimbra, 3001-401, Coimbra, Portugal.
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Knapp CM, Datta S, Ciraulo DA, Kornetsky C. Effects of low dose cocaine on REM sleep in the freely moving rat. Sleep Biol Rhythms 2007; 5:55-62. [PMID: 18568092 DOI: 10.1111/j.1479-8425.2006.00247.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Cocaine administration can be disruptive to sleep. In compulsive cocaine users, sleep disruption may be a factor contributing to relapse. The effects of cocaine on sleep, particularly those produced by low doses, have not been extensively studied. Low dose cocaine may stimulate brain reward systems that are linked to the liability of abusing of this drug. This study was designed to assess the effects of the acute administration of low to moderate cocaine doses on sleep in the rat. Polygraphic recordings were obtained from freely moving, chronically instrumented rats over a 6-h period after the administration of either cocaine (as a 2.5-10 mg/kg intraperitoneal dose) or saline. Following cocaine administration, time spent by the rats in wakefulness increased and slow wave sleep decreased in a dose-dependent manner, compared to controls. These changes lasted between 1 to 3 h following the cocaine administration. Rapid eye movement (REM) sleep was decreased during a 2- to 3-h period following the injection of 5 and 10 mg/kg doses of cocaine. In contrast, REM sleep increased during the periods 2-4 h after the administration of 2.5 and 5 mg/kg doses of cocaine. These results indicate that sleep can be significantly altered by low doses of cocaine when administered subacutely.
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Affiliation(s)
- Clifford M Knapp
- Behavioral Pharmacology Laboratory, Boston University School of Medicine, Boston, Massachusetts, USA
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Martin TJ, Kahn W, Cannon DG, Smith JE. Self-administration of heroin, cocaine and their combination under a discrete trial schedule of reinforcement in rats. Drug Alcohol Depend 2006; 82:282-6. [PMID: 16413144 DOI: 10.1016/j.drugalcdep.2005.11.018] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/28/2005] [Revised: 11/21/2005] [Accepted: 11/22/2005] [Indexed: 10/25/2022]
Abstract
Several self-administration models have been used to study the interactions between cocaine and heroin, and the schedule of reinforcement used is an important consideration for these studies. Behavior maintained by cocaine, heroin or their combination was studied using a discrete trial schedule that has been described for cocaine self-administration previously. This schedule permits 24 h access to drug without mortality associated with unlimited access to cocaine, and provides unique measures related to the circadian pattern of drug self-administration. Cocaine and heroin combined maintained higher rates of responding compared to either drug alone when a maximum of three infusions were available each hour (DT3), and decreased food intake compared to cocaine alone. There were significantly greater numbers of hours in both the light and dark cycles during which animals self-administered heroin or the combination of cocaine/heroin compared to cocaine alone. When the FR was increased to 4 under the DT3 access conditions, responding maintained by cocaine or heroin extinguished to levels not different than those maintained by saline while food reinforcement remained intact. The combination of cocaine and heroin maintained robust responding under these conditions. This schedule of reinforcement appears to elucidate behavioral interactions between cocaine and heroin that are more complex than rate of drug consumption and may provide a procedure to address some of the issues related to co-abuse of these drugs.
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Affiliation(s)
- Thomas J Martin
- Department of Physiology and Pharmacology, Wake Forest University School of Medicine, Winston-Salem, NC, USA.
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Winger G, Galuska CM, Hursh SR, Woods JH. Relative Reinforcing Effects of Cocaine, Remifentanil, and Their Combination in Rhesus Monkeys. J Pharmacol Exp Ther 2006; 318:223-9. [PMID: 16571623 DOI: 10.1124/jpet.105.100461] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Human polydrug abusers often take combinations of opioids and stimulants, but it is not clear why. Behavioral economics with demand curve analysis is uniquely able to separate two of the possibilities: that the drug combination increases the reinforcing potency of the component drugs or that the drug combination is a more effective reinforcer than either drug alone. Rhesus monkeys self-administered a range of doses of cocaine, remifentanil, and combinations of the drugs through indwelling intravenous catheters; the number of responses required for each drug infusion increased across drug-availability sessions. Combining small doses of cocaine and remifentanil that by themselves resulted in very low rates of responding yielded rates of responding that were higher than the maximum maintained by any dose of the constituent drugs. Nevertheless, demand curve analysis demonstrated that the drug combination was equally elastic as the component drugs, indicating that it was not more effective as a reinforcer than either cocaine or remifentanil alone. This suggests that enhanced self-administration of this particular drug combination is due primarily to the drug enhancement of the potency of the other drug.
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Affiliation(s)
- G Winger
- Department of Pharmacology, University of Michigan, 1301 MSRB III, Ann Arbor, MI 48109-0632, USA.
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42
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Smith JE, Co C, Coller MD, Hemby SE, Martin TJ. Self-administered heroin and cocaine combinations in the rat: additive reinforcing effects-supra-additive effects on nucleus accumbens extracellular dopamine. Neuropsychopharmacology 2006; 31:139-50. [PMID: 15956989 PMCID: PMC4048550 DOI: 10.1038/sj.npp.1300786] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The concurrent use of cocaine and opiate combinations (speedball) has increased since the 1970s and now represents a growing subset of intravenous drug abusers. An isobolographic analysis was applied to the ascending limb of the dose-effect curves for rat self-administration of cocaine, heroin, and their combination to determine the nature of the interaction. The addition of heroin to cocaine shifted the dose-effect curve for self-administration to the left, and the modulation in reinforcing efficacy of the combination of cocaine and heroin was found to be additive. A second experiment used microdialysis to determine the effects of this drug combination on nucleus accumbens (NAc) extracellular levels of dopamine ([DA](e)) in rats self-administering low doses of cocaine, heroin, or cocaine/heroin combinations. These doses of cocaine and cocaine/heroin combinations significantly increased NAc [DA](e), while heroin alone did not. The ratio of the % baseline of [DA](e) (or the dialysate concentrations of DA) to cocaine in the dialysate was higher during self-administration of cocaine/heroin combinations than with cocaine alone. These data indicate that although the interaction between cocaine and heroin in maintaining self-administration is additive, a potentiation of NAc dopaminergic neurotransmission is present, suggesting that NAc [DA](e) may not be a direct measure of reinforcing efficacy and/or it is not central to the mediation of the self-administration of this drug combination.
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Affiliation(s)
- James E Smith
- Center for the Neurobiological Investigation of Drug Abuse, Department of Physiology and Pharmacology, Wake Forest University School of Medicine, Wake Forest University, Winston-Salem, NC, USA.
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43
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Abstract
The authors argue that drug taking is an operant behavior that is reinforced by the drug itself. The effectiveness of a drug as a reinforcer is modulated by sensitization and habituation to the drug as it is consumed. According to this model, drug taking stops when habituation reduces the ability of the drug to reinforce its own consumption. Drug taking resumes when spontaneous recovery restores the effectiveness of the drug as a reinforcer. This parsimonious model provides a framework for understanding many findings in the drug literature, including acute and chronic tolerance, the effect of deprivation on consumption, the contextual specificity of tolerance, polydrug abuse, cross-sensitization between stress and drugs, behavioral sensitization, priming, and reinstatement. Although this model cannot explain all aspects of drug taking (e.g., the effect of cognitive manipulations), it has many implications for understanding and controlling human drug consumption and addiction.
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Affiliation(s)
- Frances K McSweeney
- Department of Psychology, Washington State University, Pullman, WA 99164, USA.
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Negus SS. Interactions between the reinforcing effects of cocaine and heroin in a drug-vs-food choice procedure in rhesus monkeys: a dose-addition analysis. Psychopharmacology (Berl) 2005; 180:115-24. [PMID: 15696330 DOI: 10.1007/s00213-004-2133-y] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/28/2004] [Accepted: 11/30/2004] [Indexed: 11/25/2022]
Abstract
RATIONALE Concurrent abuse of cocaine and heroin is a common form of polydrug abuse, but the interactions between the reinforcing effects of cocaine and heroin are poorly understood. Dose-addition analysis is a tool for the quantitative assessment of drug interactions, but this analysis has not been applied to evaluation of the reinforcing effects of cocaine and heroin. OBJECTIVES To evaluate interactions between the reinforcing effects of cocaine and heroin using dose-addition analysis. METHODS Rhesus monkeys were trained under a concurrent-choice schedule of food delivery (1 gm pellets) and drug injections (cocaine or heroin, 0-0.1 mg kg(-1) injection(-1)). Full dose-effect curves were determined for cocaine alone and heroin alone. Subsequently, full dose-effect curves were determined for three fixed-proportion mixtures of cocaine and heroin (fixed proportions of 1:3.2, 1:1 and 3.2:1 cocaine/heroin). Dose-addition analysis was used to assess whether cocaine/heroin interactions were super-additive, additive, or sub-additive. RESULTS Cocaine, heroin, and all cocaine/heroin mixtures maintained dose-dependent and monotonic increases in drug choice and dose-dependent decreases in response rates. Choice dose-effect curves for cocaine/heroin mixtures were shifted to the left of dose-effect curves for cocaine or heroin alone, and dose-addition analysis indicated that cocaine/heroin interactions on drug choice were sub-additive or additive. Cocaine/heroin interactions on response-rate measures were also sub-additive or additive. CONCLUSIONS These results confirm that mixtures of cocaine and heroin produce reinforcing effects in rhesus monkeys; however, cocaine/heroin interactions were only or sub-additive or additive. Thus, these results do not support the hypothesis that simultaneously delivered cocaine and heroin produces super-additive reinforcing effects.
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Affiliation(s)
- S Stevens Negus
- Alcohol and Drug Abuse Research Center, Harvard Medical School, McLean Hospital, 115 Mill St., Belmont, MA 02478, USA.
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Cornish JL, Lontos JM, Clemens KJ, McGregor IS. Cocaine and heroin ('speedball') self-administration: the involvement of nucleus accumbens dopamine and mu-opiate, but not delta-opiate receptors. Psychopharmacology (Berl) 2005; 180:21-32. [PMID: 15682301 DOI: 10.1007/s00213-004-2135-9] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/07/2004] [Accepted: 11/22/2004] [Indexed: 10/25/2022]
Abstract
RATIONALE The combined administration of heroin and cocaine ('speedball') is common among intravenous drug users. Dopamine receptors in the nucleus accumbens play a key role in cocaine self-administration; however, their role in speedball self-administration is unknown, as is the role of opiate receptors in this region. OBJECTIVES The effect of blocking dopamine D1, D2, mu-opiate or delta-opiate receptors in the nucleus accumbens on the intravenous self-administration of combined heroin and cocaine was examined in rats. METHODS Rats with bilateral cannulae implanted into the nucleus accumbens were trained to self-administer intravenous speedball (ratio of cocaine/heroin, 17:1) under a progressive ratio (PR) schedule. Prior to their self-administration session, rats were then microinjected with the dopamine D1 receptor antagonist SCH 23390 (1 and 6 nmol side(-1)), the D2 receptor antagonist raclopride (3 and 10 nmol side(-1)), the mu-opiate receptor antagonist CTOP (0.1, 0.3 and 1.0 nmol side(-1)), the delta-opiate receptor antagonist naltrindole (1.0, 3.0 and 10 nmol side(-1)) or a cocktail of SCH 23390 (1 nmol side(-1)) and CTOP (0.1 nmol side(-1)) into the nucleus accumbens. RESULTS Microinjection of SCH 23390, raclopride or CTOP into the nucleus accumbens produced dose-dependent decreases in breakpoints under the PR schedule, while naltrindole was without effect. The highest dose of SCH 23390 also significantly reduced locomotor activity measured during speedball self-administration. The combination of SCH 23390 and CTOP significantly reduced breakpoints, while not affecting locomotor activity. CONCLUSIONS These results indicate that dopamine and mu-opiate receptors, but not delta-opiate receptors, in the nucleus accumbens are involved in the reinforcing effects of speedball. Combined administration of D1 and mu-opiate receptor antagonists may be more selective at reducing the reinforcing effects of speedball self-administration than either drug alone.
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MESH Headings
- Animals
- Cocaine/administration & dosage
- Cocaine/pharmacology
- Dose-Response Relationship, Drug
- Drug Interactions
- Heroin/administration & dosage
- Heroin/pharmacology
- Male
- Nucleus Accumbens/drug effects
- Nucleus Accumbens/metabolism
- Rats
- Receptors, Dopamine/physiology
- Receptors, Dopamine D1/physiology
- Receptors, Dopamine D2/physiology
- Receptors, Opioid/physiology
- Receptors, Opioid, mu/physiology
- Receptors, sigma/physiology
- Reinforcement Schedule
- Self Administration
- Substance Abuse, Intravenous/metabolism
- Substance Abuse, Intravenous/physiopathology
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Guzman D, Ettenberg A. Heroin attenuates the negative consequences of cocaine in a runway model of self-administration. Pharmacol Biochem Behav 2005; 79:317-24. [PMID: 15501308 DOI: 10.1016/j.pbb.2004.08.009] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/03/2004] [Revised: 07/26/2004] [Accepted: 08/04/2004] [Indexed: 10/26/2022]
Abstract
It has been presumed that the combination of cocaine (COC)+heroin (HER) is more reinforcing than either of the two drugs alone, thus leading to their coadministration ("speedballing"). An alternative hypothesis is that HER serves to attenuate the undesired negative effects of COC. To test this notion, male Sprague-Dawley rats (n=31) were trained to run a straight alley for a daily intravenous (IV) injection of COC (1.0 mg/kg/injection) for 14 trials. Studies in our laboratory have shown that such animals begin to exhibit approach-avoidance behaviors ("retreats") stemming from concurrent positive and negative associations with the goal box (which, in turn, are the result of COC's immediate rewarding and subsequent dysphoric actions). Thus, retreats can be used as a reliable index of COC's anxiogenic side effects. Following 14 COC-reinforced trials, animals were split into three groups matched on mean retreat frequency. One group (n=11) received IV COC (1.0 mg/kg/injection) for seven additional trials; the remaining two groups (n=10 each) received an IV injection of COC mixed in a single solution with either a low dose (0.025 mg/kg/injection) or a high dose (0.1 mg/kg/injection) of HER. It was hypothesized that adding HER would attenuate the negative consequences of COC administration and thereby produce a reliable decrease in the occurrence of retreats. The resulting data were consistent with this hypothesis, suggesting that "speedballing" in human addicts may be motivated by a desire to reduce the negative impact of COC use.
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Affiliation(s)
- Daniel Guzman
- Behavioral Pharmacology Laboratory, Department of Psychology (9660), University of California, Santa Barbara, CA 93106, USA
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Ward SJ, Morgan D, Roberts DCS. Comparison of the reinforcing effects of cocaine and cocaine/heroin combinations under progressive ratio and choice schedules in rats. Neuropsychopharmacology 2005; 30:286-95. [PMID: 15578009 DOI: 10.1038/sj.npp.1300560] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The co-use of cocaine and heroin is relatively common, with a growing clinical and preclinical literature dedicated to investigating the factors underlying the phenomenon. Specifically, several studies have compared the reinforcing effects of the coadministration of cocaine and heroin, referred to commonly as 'speedball', to either drug alone. The present study assessed whether addition of heroin to a wide range of cocaine doses produces reinforcing effects greater than cocaine alone using both a progressive ratio (PR) schedule and a choice procedure. Patterns of coadministration of cocaine and heroin offered simultaneously were also assessed using double-lumen cannulas. Under the PR schedule, speedball combinations across a range of doses (0.38-3.0 mg/kg/inf cocaine+1.5-48 microg/kg/inf heroin) did not support higher break points than cocaine alone. When cocaine and heroin were made available concurrently (ie on two separate levers), rats self-administered cocaine exclusively. Using a choice procedure, however, a preference was demonstrated for some speedball combinations (eg 0.18 mg/kg/inf cocaine+50 microg/kg/inf heroin; 0.38 mg/kg/inf cocaine+50 microg/kg/inf heroin) over cocaine alone (0.75 mg/kg/inf). So while results obtained using the PR schedule do not support the hypothesis that speedball combinations are more reinforcing than cocaine alone, data from the choice procedure do support this hypothesis. These apparently discrepant results demonstrate that these models are measuring different aspects of drug reinforcement, and suggest that choice procedures in rats provide a useful tool to study speedball self-administration.
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Affiliation(s)
- Sara Jane Ward
- Neuroscience Program, Wake Forest University School of Medicine, Winston-Salem, NC, USA
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48
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Leri F, Tremblay A, Sorge RE, Stewart J. Methadone maintenance reduces heroin- and cocaine-induced relapse without affecting stress-induced relapse in a rodent model of poly-drug use. Neuropsychopharmacology 2004; 29:1312-20. [PMID: 15039768 DOI: 10.1038/sj.npp.1300435] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Although it is well established that methadone can be an effective treatment for opiate addiction, it is not clear how methadone maintenance affects cocaine use and cravings in individuals who self-administer both opiates and cocaine. In our attempt to explore the effect of methadone maintenance on the effects of cocaine, we first assessed the locomotor stimulatory effects of cocaine in rats maintained on methadone (0, 10, 20, or 30 mg/kg/day, via osmotic minipumps). Chronic methadone elevated baseline locomotion in a dose-dependent manner and did not reduce the direct stimulatory effects of cocaine (5 mg/kg). We then investigated the effects of the highest methadone maintenance dose (30 mg/kg/day) on heroin and cocaine seeking in extinction, and when it was precipitated by exposure to heroin, cocaine, or foot-shock stress in rats trained to self-administer both drugs in the same experimental context (heroin 0.05 mg/kg/inf; cocaine 0.5 mg/kg/inf, eight 3-h sessions each). In tests of reinstatement, rats responded selectively on the appropriate drug-associated lever after priming injections of heroin (0.25 mg/kg) or cocaine (20 mg/kg). Methadone maintenance blocked both cocaine- and heroin-induced reinstatement, but not stress-induced reinstatement, which was not lever selective. These results suggest that although methadone maintenance may not reduce the direct stimulatory effects of cocaine, it has the potential to reduce both spontaneous and cocaine-primed cocaine-seeking behavior.
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Affiliation(s)
- Francesco Leri
- Department of Psychology, University of Guelph, Guelph, Ontario, Canada.
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Sizemore GM, Davies HML, Martin TJ, Smith JE. Effects of 2beta-propanoyl-3beta-(4-tolyl)-tropane (PTT) on the self-administration of cocaine, heroin, and cocaine/heroin combinations in rats. Drug Alcohol Depend 2004; 73:259-65. [PMID: 15036548 DOI: 10.1016/j.drugalcdep.2003.10.013] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/25/2003] [Revised: 09/30/2003] [Accepted: 10/15/2003] [Indexed: 11/17/2022]
Abstract
Pharmacotherapies utilizing long-acting agonists and mixed function agonists-antagonists have been successful in the treatment of opiate addiction but no comparable treatment exists for cocaine abuse. Long-acting tropane analogues have been synthesized that could be candidates for such pharmacotherapies. 2beta-propanoyl-3beta-(4-tolyl)-tropane (PTT) is one such compound that is a relatively selective dopamine (DA) transporter blocker that has a significantly longer duration of action than cocaine. The purpose of this study was to assess the effects of PTT on the intravenous self-administration of cocaine, heroin, or cocaine/heroin combinations. Groups of rats were trained to self-administer cocaine, heroin, or cocaine/heroin combinations using a within session dosing procedure in which three doses were available each session. PTT pretreatment reduced cocaine and cocaine/heroin combinations intake in a dose-dependent manner while having only minor effects on heroin intake. These results suggest that the neurobiological substrates of cocaine and heroin self-administration are different, and that these cocaine/heroin combinations may function more like cocaine alone, even when the dose of heroin in the mixture will function independently as a reinforcer. These results further support the potential use of long-acting dopamine reuptake inhibitors as pharmacotherapeutic adjuncts to a comprehensive treatment program for cocaine and cocaine/heroin abuse.
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Affiliation(s)
- Glen M Sizemore
- Department of Psychology, University of Florida, Box 112250, Gainesville, FL 32611, USA
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50
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Ikegami A, Duvauchelle CL. Nucleus accumbens and medial prefrontal cortex dopaminergic response to self-administered cocaine in naive rats. Neurosci Lett 2004; 354:205-8. [PMID: 14700732 DOI: 10.1016/j.neulet.2003.10.033] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Cocaine reinforcement is strongly associated with increased nucleus accumbens dopamine (NAcc DA). The involvement of medial prefrontal cortex (mPFC) DA in cocaine reward is less defined, but substantial evidence indicates that increased mPFC DA may suppress NAcc DA levels. Using in vivo microdialysis, NAcc or mPFC DA was determined in cocaine-naive rats after a self-administered cocaine injection (3.0 mg/kg). Extracellular levels of NAcc DA were dramatically enhanced 10 min post-cocaine injection, but dropped significantly at each subsequent assessment. mPFC DA also increased significantly, but to a lesser extent than observed in the NAcc. Findings of prominent DA increases in both the NAcc and mPFC terminals during the test session indicate that NAcc DA responses do not appear to be inhibited by increased mPFC DA during cocaine self-administration.
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Affiliation(s)
- Aiko Ikegami
- College of Pharmacy, Division of Pharmacology and Toxicology and the Waggoner Center for Alcohol and Addiction Research, The University of Texas, Austin, TX 78712-0125, USA
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