PT  - JOURNAL ARTICLE
AU  - S. S. Negus
AU  - M. H. Baumann
AU  - R. B. Rothman
AU  - N. K. Mello
AU  - B. E. Blough
TI  - Selective Suppression of Cocaine- versus Food-Maintained Responding by Monoamine Releasers in Rhesus Monkeys: Benzylpiperazine, (+)Phenmetrazine, and 4-Benzylpiperidine
AID  - 10.1124/jpet.108.143701
DP  - 2009 Apr 01
TA  - Journal of Pharmacology and Experimental Therapeutics
PG  - 272--281
VI  - 329
IP  - 1
4099  - http://jpet.aspetjournals.org/content/329/1/272.short
4100  - http://jpet.aspetjournals.org/content/329/1/272.full
SO  - J Pharmacol Exp Ther2009 Apr 01; 329
AB  - Monoamine releasers constitute one class of drugs currently under investigation as potential agonist medications for the treatment of cocaine dependence. The efficacy and safety of monoamine releasers as candidate medications may be influenced in part by their relative potency to release dopamine and serotonin, and we reported previously that releasers with approximately 30-fold selectivity for dopamine versus serotonin release may be especially promising. The present study examined the effects of the releasers benzylpiperazine, (+)phenmetrazine, and 4-benzylpiperidine, which have 20- to 48-fold selectivity in vitro for releasing dopamine versus serotonin. In an assay of cocaine discrimination, rhesus monkeys were trained to discriminate 0.4 mg/kg i.m. cocaine from saline in a two-key, food-reinforced procedure. Each of the releasers produced a dose- and time-dependent substitution for cocaine. 4-Benzylpiperidine had the most rapid onset and shortest duration of action. Phenmetrazine and benzylpiperazine had slower onsets and longer durations of action. In an assay of cocaine self-administration, rhesus monkeys were trained to respond for cocaine injections and food pellets under a second order schedule. Treatment for 7 days with each of the releasers produced a dose-dependent and selective reduction in self-administration of cocaine (0.01 mg/kg/injection). The most selective effects were produced by phenmetrazine. Phenmetrazine also produced a downward shift in the cocaine self-administration dose effect curve, virtually eliminating responding maintained by a 30-fold range of cocaine doses (0.0032–0.1 mg/kg/injection) while having only small and transient effects on food-maintained responding. These findings support the potential utility of dopamine-selective releasers as candidate treatments for cocaine dependence. U.S. Government work not protected by U.S. copyright