EFFECT OF CORTICOTROPIN RELEASING HORMONE AND NEUROPEPTIDE-Y ON ELECTROPHYSIOLOGICAL ACTIVITY OF SYMPATHETIC-NERVES TO INTERSCAPULAR BROWN ADIPOSE-TISSUE

It has been proposed that there is a reciprocal relationship between food intake and sympathetic activity. To test this hypothesis corticotropin releasing hormone, which suppresses feeding behavior, and neuropeptide Y, which stimulates it, were injected intracerebroventricularly and sympathetic nerve activity to interscapular brown adipose tissue measured in anesthetized rats. Multi-unit discharges of sympathetic nerves to interscapular brown adipose tissue were recorded electrophysiologically. The intracerebroventricular injection of corticotropin releasing hormone (250 and 500 pmol) increased sympathetic nerve activity and the intracerebroventricular injection of neuropeptide Y (250-500 pmol) suppressed sympathetic nerve activity in a dose-dependent manner. The intracerebroventricular injection of vehicle did not affect sympathetic nerve activity. The result is consistent with the hypothesis that these brain peptides are neuromodulators of the sympathetic nervous system which may control energy expenditure in interscapular brown adipose tissue. The effects of these two brain peptides on sympathetic nerve activity are opposite to their effects on feeding behavior suggesting that sympathetic activity and food intake may be reciprocally related. © 1990.