Gamma-vinyl gamma-aminobutyric acid attenuates the synergistic elevations of nucleus accumbens dopamine produced by a cocaine/heroin (speedball) challenge
Gerasimov MR, Dewey SL
Department of Chemistry,
Brookhaven National Laboratory,
Upton, NY 11973, USA.
Eur J Pharmacol 1999 Sep 3;380(1):1-4


In the present study, we examined the effect of an acute administration of the selective suicide inhibitor of gamma-aminobutyric acid (GABA)-transaminase, gamma-vinyl GABA on increases in nucleus accumbens dopamine produced by a cocaine/heroin challenge in freely moving animals. Cocaine (20 mg/kg, i.p.) produced an elevation in extracellular nucleus accumbens dopamine of approximately 380% above baseline, while heroin produced only a moderate increase of 70%. Coadministration of these two drugs, however, produced a synergistic elevation in nucleus accumbens dopamine of 1000%. This response was reduced by 50% in animals pretreated with gamma-vinyl GABA (300 mg/kg, i.p.) 2.5 h prior to challenge. This same dose of gamma-vinyl GABA inhibited cocaine-induced increases in nucleus accumbens dopamine by 25% and completely abolished heroin-induced increase. These findings indicate that gamma-vinyl GABA can interfere with the synergistic effects produced by the combination of an indirect dopamine releaser (heroin) and a dopamine reuptake blocker (cocaine).
Opium timeline
Rats on speedballs
Monkeys on speedballs
Rodent polydrug abusers
Nicotine, heroin and cocaine
Methylphenidate and cocaine
Freebasing flies go hyperkinetic
Dopamine levels in speedballing rats

and further reading

Future Opioids
BLTC Research
Utopian Surgery?
The Abolitionist Project
The Hedonistic Imperative
The Reproductive Revolution
Critique of Huxley's Brave New World

The Good Drug Guide
The Good Drug Guide

The Responsible Parent's Guide
To Healthy Mood Boosters For All The Family