Peripheral atropinization does not change meal size controlled by prepyloric mechanisms.

To investigate the role of gastric contractility in the prepyloric control of meal size, we administered atropine methyl nitrate (3 mg/kg,ip) or saline prior to 30-min tests on 3 separate days in which 0.8 M sucrose was ingested by rats after 1 h of food deprivation. Ingested 0.8 M sucrose accumulated in the stomach and did not empty into the small intestine during the test because the pylorus of each rat was closed by inflation of a chronic pyloric cuff. Atropine methyl nitrate had no significant effect on 30-min intake or on the pattern of intake observed at 3-min intervals during the test on any of the three test days. Thus, neither acute nor repetitive experience with atropine methyl nitrate changed the pattern or volume of intake. These results suggest that gastric contractile responses elicited by the intragastric accumulation of 0.8M sucrose during ingestion are not necessary for the control of meal size by prepyloric mechanisms.