Rationale: 2beta-propanoyl-3beta-(4-tolyl)-tropane (PTT) is a cocaine analog with high affinity at and selectivity for the dopamine transporter (DAT). 2beta-propanoyl-3beta-(2-naphthyl)-tropane (HD-23), like cocaine, binds with approximately equal affinity to the DAT, the serotonin transporter, and the norepinephrine transporter but has over a 100-fold higher affinity for these monoamine transporters than cocaine. The reinforcing effects of these drugs have not been evaluated in cocaine-na nonhuman primates.
Objective: The primary goal of the present study was to examine the reinforcing effects of PTT and HD-23 in rhesus monkeys before and after a history of intravenous cocaine self-administration.
Methods: Monkeys (n=4) were initially trained to respond under a fixed-ratio 30 schedule of food presentation. When responding was stable, saline, PTT (0.001-0.03 mg/kg per injection), and HD-23 (0.0003-0.0056 mg/kg per injection) were made available for self-administration for least five sessions per dose. Next, a cocaine dose-effect function (0.0003-0.3 mg/kg per injection) was determined and then