Rewarding and aversive properties of IP and SC cocaine: assessment by place and taste conditioning.

Three experiments were conducted to compare the effectiveness of intraperitoneally (IP) administered or subcutaneously (SC) administered cocaine to produce place and/or taste conditioning after four conditioning trials. In each experiment, IP (5-20 mg/kg) cocaine produced a place preference, but SC (0.5-20 mg/kg) cocaine at concentrations that prevented necrosis, did not produce a place preference. The failure of SC cocaine to produce a place preference was not a function of conditioning trial duration. On the other hand, SC cocaine (20 mg/kg) produced conditioned taste avoidance, but IP cocaine (20 mg/kg) did not produce conditioned taste avoidance. The results suggest that IP cocaine, but not SC cocaine, is rewarding.