Tolerance to cocaine-induced convulsions in the cat.

Two groups of female cats (6 each) were used: (1) a seizure group which received a minimum convulsive dose (MCD) of cocaine i.v., and (2) a subseizure group which received a subconvulsive dose of cocaine i.v., for 13 successive days. Determination of the MCD across 13 days in the seizure group and on Day 14 in the subseizure group revealed significant tolerance to cocaine-induced convulsions. However, reverse tolerance to cocaine-induced abnormal behavior developed as dystonic posture and speed of stereotyped movement increased during the 13-day treatment period in the subseizure group. These data are discussed in terms of local anesthetic and catecholaminergic effects of cocaine, as well as possible differential effects of various routes of administration.