Cocaine-induced taste aversions: Effect of route of administration

Female Long-Evans rats were given saccharin followed by either intraperitoneal (ip) or subcutaneous (sc) cocaine (18, 32 or 50 mg/kg) or vehicle. Aversions induced by ip-administered cocaine were weak, with a decrease in consumption of 35% on the final conditioning trial. Aversions induced by sc-administered cocaine were robust, with subjects receiving the two highest doses of cocaine decreasing saccharin consumption by 95 and 98%, respectively. Although several possibilities exist for the differential ability of ip and sc cocaine to induce taste aversions, the basis for this difference remains unknown. While all subjects receiving ip cocaine maintained or increased in body weight, subjects receiving the two highest doses of sc cocaine decreased in body weight. Independent of the mechanism underlying the differential ability of ip and sc administration to induce taste aversions and affect body weight, route of administration may play an important role in the behavioral toxicity of cocaine.