Effects of Chlorpromazine on Fear-Motivated Behavior, Urinary Cortisol, Urinary Volume and Heart Rate in the Dog

Abstract

Several doses of chlorpromazine (6.25, 12.5, 25.0 mg) were administered to dogs while they were subjected to a Sidman nondiscriminated avoidance schedule which contained 7 conditioned stimuli-unavoidable shock (CS-US) pairings. The drug consistently reduced baseline response rate and enhanced shock rate. Facilitation of heart, response, and activity rates normally noted during the aversive CS were unaffected by administration of the drug. In addition, the over-all heart rate, urinary volume, and urinary Cortisol measures showed no consistent pattern of results in response to drug administration. These results suggest that under this schedule of reinforcement only baseline response rate was sensitive to the anxiolytic effects of chlorpromazine.