RECIPROCAL RELATION BETWEEN THE SYMPATHETIC NERVOUS-SYSTEM AND FOOD-INTAKE

The present studies have examined the hypothesis that food intake and sympathetic activity are inversely related. Following lateral hypothalamic lesions, food intake decreases and sympathetic activity rises. When pair-gained animals are used, the sympathetic activity of the LH-lesioned animals is above that of ad lib fed controls, and the sympathetic activity of the pair-gained animals is below that of the controls. With VMH-lesions, food intake rises and sympathetic activity falls. Several drugs, including 2-deoxy-D-glucose, fenfluramine, corticotropin releasing hormone, and neuropeptide Y, all show this reciprocal relationship. Three exceptions to this rule, the rat with a PVN lesion, cold exposure and animals eating a highly palatable diet, are discussed. Under the usual circumstances, the sympathetic activity appears to play a tonic role in regulating the onset of a meal, and the acute changes in sympathetic activity after eating may play a role in the onset of satiety.