Immediate acceptance of minerals and HCl by calcium-deprived rats: brief exposure tests

We conducted two experiments to test the hypothesis that calcium consumption by calcium-deprived rats is unlearned and guided by oral cues. In experiment 1, we gave 23.5-h water-deprived control and calcium-deprived rats 30-min tests with water and various taste solutions. Relative to controls, calcium-deprived rats licked significantly less water and more 300 mM Ca.lactate in the first minute, more 50 mM HCl and 125 mM HCl in the first 10 min, and more 75 mM CaCl2, 150 mM CaCl2, and 300 mM CaCl2 by the end of the 30-min session. There was no difference between the groups at any time in lick rates for sodium solutions, quinine hydrochloride, sucrose octaacetate, or saccharin. In experiment 2, we gave 23-h water-deprived control, calcium-deprived, and sodium-deprived rats 10-min tests. During the first minute, calcium-deprived rats licked more than did control and sodium-deprived rats for 100 mM CaCl2, 100 mM FeCl2, and 20 mM Pb.acetate. Sodium-deprived rats licked more than did control and calcium-deprived rats for 600 mM NaCl and less than did controls for 200 mM L-histidine. At the end of the 10-min session, sodium-deprived rats had higher lick rates for 100 mM FeCl2 than did control rats. There were no differences between the groups in lick rates for 1 mM quinine hydrochloride, 100 mM SrCl2, or 20 mM citric acid. The results suggest that calcium-deprived rats use innate oral factors to guide consumption of calcium and other solutions.