Verapamil suppresses d-amphetamine-induced place preference conditioning.

The effect of pretreatment with (+/-)-verapamil (5, 10 or 15 mg/kg, i.p.) on place preference induced with d-amphetamine (1 mg/kg, i.p. 40 min after verapamil) was studied in male rats. Place preference conditioning was performed using two-compartment shuttle boxes and 8 alternating stimulant/saline sessions. Verapamil dose-dependently suppressed amphetamine-induced place preference. No significant changes in place preference were observed following 8 alternating verapamil (no stimulant)/saline sessions, irrespective of whether verapamil injections were paired with the originally less or the originally more preferred compartment. It appears that verapamil effectively suppresses the reinforcing properties of d-amphetamine in the paradigm used.