RTI 113, a 3-phenyltropane analog, produces long-lasting cocaine-like discriminative stimulus effects in rats and squirrel monkeys

The 3-phenyltropane analog, 3beta-(4-chlorophenyl)tropane-2beta-carboxylic acid phenyl ester hydrochloride (RTI 113), has been shown to decrease cocaine self-administration in rats, squirrel monkeys and rhesus monkeys. Consequently, it has been proposed as a potential agonist pharmacotherapy for cocaine dependence. However, the time course of the discriminative stimulus effects of RTI 113 has not been determined. The present study was designed to compare the time course of the discriminative stimulus effects of RTI 113 with that of cocaine in rats and squirrel monkeys. Tests were conducted using a drug discrimination procedure in which rats and squirrel monkeys were trained to discriminate 10 and 0.3 mg/kg cocaine from saline, respectively. RTI 113 substituted for cocaine in both species, The time course of the discriminative stimulus effects of RTI 113 was approximately five times longer compared to that of cocaine. RTI 113 is a 3-phenyltropane analog that has long acting cocaine-like discriminative stimulus effects in both rats and squirrel monkeys. These results, combined with those indicating that RTI 113 decreases cocaine self-administration, suggest that RTI 113, or analogs of RTI 113, may be useful tools for developing potential agonist therapies for cocaine dependence. (C) 2002 Elsevier Science B.V All rights reserved.