Effects of atropine methyl nitrate on sham feeding in the rat

The purpose of this experiment was to clarify the effects of administration of peripheral cholinergic blocking agents on sham feeding. Rats were implanted with chronically indwelling gastric cannulae and allowed to sham feed sucrose solutions varying in their degree of diet palatability. Prior to the sham feeding tests, rats received an intraperitoneal injection of either atropine methyl nitrate (250 micrograms/kg) or a control substance, physiological (0.9%) saline. The results indicated that atropine methyl nitrate inhibited sham feeding at all levels of diet palatability tested. This reduction in food intake level following drug administration was apparent from the initiation of the sham feeding bout and did not result from a more rapid cessation of feeding under the drug condition. Further, similar doses of AMN did not reduce sham drinking of water in water-deprived animals. The implications of these findings to a cholinergic involvement in food intake control systems are discussed.