alexa Increased mesolimbic GABA concentration blocks heroin self-administration in the rat.


Journal of Addiction Research & Therapy

Author(s): Xi ZX, Stein EA

Abstract Share this page

Abstract Opiate reinforcement has been hypothesized to be mediated by an inhibition of mesolimbic gamma-aminobutyric acid (GABA) release that subsequently disinhibits ventral tegmental area (VTA) dopamine neurons. In support of this hypothesis, this study demonstrates that when administered directly into the lateral ventricle, the VTA, or the ventral pallidum, but not the nucleus accumbens, gamma-vinyl-GABA (GVG, an irreversible GABA-transaminase inhibitor, 20-50 microg) dose dependently blocked heroin (0.06 mg/kg) self-administration (SA), as assessed by an increase in heroin SA at low doses of GVG and an initial increase followed 1 to 2 h later by a blockade of heroin SA at higher GVG doses. This effect lasted 3 to 5 days. In drug-naïve rats, intra-VTA GVG pretreatment also prevented or delayed acquisition of heroin SA for 2 days. This GVG effect was prevented or reversed by systemic or intra-VTA pretreatment with the GABA(B) antagonist 2-hydroxysaclofen, but not the GABA(A) antagonist bicuculline. Similarly, coadministration of heroin with aminooxy-acetic acid (1-4 mg/kg) or ethanolamine-O-sulfate (50-100 mg/kg), two reversible GABA transaminase inhibitors, dose dependently reduced heroin reinforcement. Coadministration of (+/-)-nipecotic acid (0.1-5 mg/kg) with heroin, or intra-VTA or -ventral pallidum pretreatment with (+/-)-nipecotic acid (10 microg) or NO-711 (2 microg), two GABA uptake inhibitors, significantly increased heroin SA behavior, an effect also blocked by systemic 2-hydroxysaclofen, but not bicuculline. Taken together, these experiments, for the first time, demonstrate that pharmacological elevation of mesolimbic GABA concentration blocks heroin reinforcement by activating GABA(B) receptors, supporting the GABAergic hypothesis of opiate reinforcement and the incorporation of GABA agents in opiate abuse treatment.
This article was published in J Pharmacol Exp Ther and referenced in Journal of Addiction Research & Therapy

Relevant Expert PPTs

Relevant Speaker PPTs

Recommended Conferences

Relevant Topics

Peer Reviewed Journals
Make the best use of Scientific Research and information from our 700 + peer reviewed, Open Access Journals
International Conferences 2017-18
Meet Inspiring Speakers and Experts at our 3000+ Global Annual Meetings

Contact Us

© 2008-2017 OMICS International - Open Access Publisher. Best viewed in Mozilla Firefox | Google Chrome | Above IE 7.0 version