Abstract
The neural mechanism of discriminative taste preference learning was examined using the modified procedure of flavor-postingestive consequence learning paradigm in C57BL/6 male mice. Mice under a food restriction schedule were given six two-bottle training sessions with the four exposures of 0.15 M sucrose (Suc) paired with intragastric (IG) 0.5 M Suc infusion and those of 5 mM saccharin (Sacch) paired with IG water infusion with an alternative sequence. The intake of Suc significantly increased with decreasing of that of Sacch, and the increasing of a preference for Suc was suppressed when the mice received the simultaneous IG infusion of 2 mM phloridzin dehydrate, a blocker of Na-glucose transporter at the intestine. Lesions of the amygdala with ibotenic acid impaired development of a preference for Suc. These results suggest that learned preference for Suc is mediated by the absorption of glucose produced from the injected sucrose at the intestine, and the amygdala plays a role in discriminative association of hedonically positive visceral signal of glucose with the sweet taste quality of Suc. [J Physiol Sci. 2007;57 Suppl:S138]
