Abstract
Our previous study showed that zinc-deficient mice had lower lick rates for 10-30 mM calcium chloride than did control mice. In this study, we investigated the effects of repletion with dietary zinc and of dissection of the chorda tympani and glossopharyngeal nerves on the ingestion of calcium chloride and sodium chloride solutions in zinc-deprived mice. Behavioral responses were examined by using a 10-s lick test and a 48-h two-bottle choice test between a solution and water. Relative to control mice fed the zinc-replete diet, those fed the zinc-deficient diet had decreased intakes of 0.01 M calcium chloride in both the 10-s and 48-h tests. On the other hand, dietary zinc deficiency increased the intakes of 0.1 M sodium chloride in the 48-h tests, but not in the 10-s tests. When the zinc-deficient mice were fed a zinc-replete diet for 2 weeks, reduced intakes of calcium chloride and increased intakes of sodium chloride disappeared. Both the taste denervated and sham-operated mice, fed the zinc-deficient diet, had lower intakes of 0.01 M calcium chloride and higher intakes of 0.1 M sodium chloride than control mice with intact or sham-operated taste nerves. Thus, the results suggest that unusual intakes of calcium chloride and sodium chloride by the deficient mice are recovered by repletion with dietary zinc for 2 weeks, and that taste information conveyed by the taste nerves does not play an essential role in reduced acceptance of calcium chloride in zinc-deficient mice. [J Physiol Sci. 2007;57 Suppl:S184]
