Lesions of the ventromedial hypothalamic nucleus enhance sympatho-adrenal function.

The effects of lesions of the ventromedial hypothalamic nucleus (VMH) on the sympatho-adrenal function were investigated in anesthetized rats using electrophysiological and biochemical techniques. Lesions of this nucleus produced a gradual but strong increase in the efferent activity of the adrenal sympathetic nerves. Catecholamine secretion from the adrenal medulla was also facilitated by VMH lesions. The results indicate that the catecholamines from the adrenal medulla might be involved in the development of metabolic disorders seen during VMH syndrome.