Effects of vasopressin on multiple fixed-ratio fixed-interval schedules of reinforcement

The effect of arginine- and des-glycinamide arginine vasopressin on steady-state operant responding was examined. Rats were trained to press a lever for food under a multiple fixed-interval 4-min fixed-ratio 30 schedule of reinforcement. Arg vasopressin (0.5 to 100μg/kg, subcutaneous) produced a dose-dependent decrease in response rate, but des-glycinamide arginine vasopressin (0.5 to l00μg/kg, subcutaneous) had no effect. Neither peptide significantly altered fixed-interval response patterning. These data suggest that vasopressin’s behavioral effects should be viewed in light of its aversive peripheral actions.