ABSTRACT
The operant behaviour in streptozotocin (45 mg or 65 mg/kg) treated rats was studied using albino rats of either sex. Animals were trained daily for 15 days in an operant chamber (Takei & Co.) to press the bar for getting the reward in the form of 45 mg food pellet following 18 hr of food deprivation. After initial training under continuous reinforcement schedule (CRF), animals were trained under FR2 and FR4 schedules, in which after every second (FR2) or every fourth bar press (FR4) rat received the pellet. The results indicate that the bar pressing for food reward is not altered after induction of experimental diabetes with streptozotocin. It is suggested that insulin lack or hyperglycaemia in this condition fails to influence higher centres associated with regulation of motivated behaviour.