Effects of angiotensin II on schedule dependent and induced behavior at recovered body weight

The effects of 4 doses of angiotensin II, 0.4, 0.8, 1.2 and 1.6 mg/kg, injected subcutaneously on schedule dependent lever pressing and schedule induced drinking and licking were studied in rats who had recovered body weight under ad lib eating conditions. Prior to this experiment rats had been maintained at 80% body weight and were tested under the usual conditions producing schedule induced drinking. Animals were then returned to the home cage and allowed to recover body weight. Results were analyzed for both the first 15 min of the 1 hr session and for the total 1 hr session. Data indicate that all four doses decreased lever pressing during the first 15 min and for the total 1 hr session. The three highest doses produced increased licking during the first 15 min. Only the highest dose augmented licking throughout the total 1 hr session. Water intakes were significantly increased by the three highest doses only during the first 15 min of the session. Peripheral effects of angiotensin II were discussed and a central pharmacological action on drinking was suggested.