Sodium depletion increases rats' preferences for salted food

In contrast to humans, sodium-replete rats prefer dilute saline to water and do not prefer salted food to plain food. Sodium depletion is known to enhance the intake of and preference for salt provided in water. Here, we examined whether the context of the delivery vehicle for salt could influence salt intake and preference. This was done by studying the effects of sodium depletion on rats' preferences for salted food and salt water. In Experiment 1, rats were depleted of sodium by combined use of a sodium-deficient diet and administration of the natriuretic drug, furosemide (5 mg sc). They were then given a choice between either salted sodium-deficient diet (1% NaCl) and unsalted sodium-deficient diet or salt water (0.3 M NaCl) and water. The rats consumed more salted than unsalted sodium-deficient diet and more 0.3 M NaCl than water. However, the amount of salt ingested in food was substantially less than the amount in water. In Experiments 2 and 3 we examined preferences for various concentrations of salt (0.06%-8.0% NaCl) in food during sodium depletion. The duration of the salted food preference was inversely related to the quantity of salt consumed and the concentration of salt in the food. Data from Experiments 4 and 5 indicated that it was unlikely the changes in salted food preference were the result of taste aversions produced by furosemide administration. Taken together, these experiments demonstrate that, as the case for fluids, a preference for salted food can be produced by sodium depletion.(ABSTRACT TRUNCATED AT 250 WORDS)