RT Journal Article
SR Electronic
T1 Drug Discrimination in Methamphetamine-Trained Monkeys: Effects of Monoamine Transporter Inhibitors
JF Journal of Pharmacology and Experimental Therapeutics
JO J Pharmacol Exp Ther
FD American Society for Pharmacology and Experimental Therapeutics
SP 720
OP 727
DO 10.1124/jpet.104.071035
VO 311
IS 2
A1 Czoty, Paul W.
A1 Ramanathan, Chinnasamy R.
A1 Mutschler, Nicole H.
A1 Makriyannis, Alexandros
A1 Bergman, Jack
YR 2004
UL http://jpet.aspetjournals.org/content/311/2/720.abstract
AB The involvement of brain monoamine systems in the discriminative stimulus effects of methamphetamine (MA) was studied in squirrel monkeys by evaluating the effects of differentially selective monoamine uptake inhibitors alone and in combination. In monkeys discriminating i.m. injections of 0.3 mg/kg MA from saline, methamphetamine (0.01-0.3 mg/kg), and dopamine transporter (DAT) inhibitors, including 1-{2-(bis(4-fluorophenyl)-methoxy)ethyl}-4-(3-phenylpropyl)piperazine (GBR 12909; 1.0-17.8 mg/kg) and its analogs AM2502 (1.0-17.8 mg/kg), AM2506 (1.0-30.0 mg/kg), AM2515 (1.0-17.8 mg/kg), and AM2517 (1.0-5.6 mg/kg), produced dose-related increases in responding on the MA-associated lever and, at the highest doses, full substitution. The time course of MA-like effects was similar for equivalent (3.0 mg/kg) doses of GBR 12909 and its most potent analog, AM2517. Unlike the DAT blockers, the selective 5-hydroxytryptamine (serotonin) uptake inhibitor clomipramine (1.0-10.0 mg/kg) and the selective norepinepherine (NE) uptake inhibitor desipramine (1.0-10 mg/kg) produced responding primarily on the saline lever. The selective NE uptake inhibitor nisoxetine partially substituted at the highest dose tested (10.0 mg/kg). Pretreatment with GBR 12909 or AM2517 enhanced the discriminative stimulus effects of MA, shifting the dose-effect curve leftward. The NE uptake inhibitors desipramine or nisoxetine also enhanced the discriminative stimulus effects of MA, whereas clomipramine only attenuated them. These results support the view that dopaminergic mechanisms play a prominent role in the discriminative stimulus effects of MA in monkeys, whereas involvement of serotonergic and noradrenergic systems may be limited to a modulatory role. The American Society for Pharmacology and Experimental Therapeutics