Selection of Nacl Solutions by Sodium-Deprived Mongolian Gerbils in Richter-Type Drinking Tests

Summary

The study investigated whether gerbils would compensate for a dietary-induced sodium deficiency by freely ingesting NaCl solutions. Accordingly, adult Mongolian gerbils were fed either a sodium-deficient diet (N = 30) or a sodium-replete ration (N = 30) for 30 days. Then, each group was divided into three subgroups (five males and five females per subgroup). One sodium-deprived subgroup and one sodium-replete subgroup were assigned to Richter-type drinking tests with each of three molar NaCl concentrations (.05 M, .15 M, and .30 M) versus water. Although the sodium-depleted animals did not lose weight, a dramatic alopecia obtained, suggesting an effective sodium deficiency. Correspondingly, the sodium-deficient gerbils demonstrated greater acceptance of, and consumed more, NaCl than the sodium-replete animals; and both these measures were concentration dependent. These results in light of previous work by the authors suggest that the gerbil is more behaviorally adaptive under conditions of gradually increasing sodium need than under the more precipitous requirements induced by adrenalectomy or formalin injections.