Strain differences in eating and drinking evoked by electrical stimulation of the hypothalamus

Abstract

Electrical stimulation of the lateral hypothalamus (ESLH) has been shown to produce individual response differences that cannot be attributed to the neuroanatomical locus of the electrode. The purpose of the present experiment was to investigate strain differences in the incidence of eating and drinking evoked by ESLH. The responses of 49 Long-Evans and 51 Sprague-Dawley male rats implanted with bilateral hypothalamic electrodes were studied. Animals from these two strains do not differ in their normal food or water consumption. Analysis of the responses to ESLH demonstrated that a significantly greater number of Long-Evans rats ate food and/or drank water during ESLH than did the Sprague-Dawley rats. These results could not be attributed to differences in electrode placements, or rearing conditions. In addition to strain differences, the importance of individual differences within each strain was demonstrated by the fact that both electrodes in a given animal commonly evoked the same behavior. Hypotheses to explain these results are discussed.