ABDOMINAL VAGOTOMY DOES NOT BLOCK CARBOHYDRATE-CONDITIONED FLAVOR PREFERENCES IN RATS

The effects of abdominal vagotomy on the flavor preferences conditione d by Polycose (a maltodextrin) were investigated in female rats. Using an oral-delay training method, a modest conditioned flavor preference (67%) was obtained in control rats but not in rats with subtotal abdo minal vagotomy (hepatic branch intact). The rats were fed a chow diet, and gastric stasis in the vagotomized rats may have interfered with p reference learning. To facilitate conditioning, the rats were switched to a liquid maintenance diet and trained with new flavors paired with intragastric (IG) infusions of Polycose and water. With this procedur e, the vagotomized and control rats acquired strong preferences (83-88 %) for the flavor paired with IG Polycose. In a second experiment, fla vor preferences conditioned by IG Polycose were obtained in rats with total abdominal vagotomy although the preference was attenuated relati ve to control rats (79% vs. 97%). Gastric motor problems (dumping) may have been a factor because the vagotomized rats consumed much less fl avored solution (and therefore received less IG Polycose) during train ing than did controls. These findings indicate that an intact vagus ne rve is not necessary to obtain carbohydrate-conditioned preferences, a lthough vagotomy may interfere with the conditioning in some experimen tal situations.