EFFECT OF GALANIN AND ENTEROSTATIN ON SYMPATHETIC-NERVE ACTIVITY TO INTERSCAPULAR BROWN ADIPOSE-TISSUE

The effects of galanin and enterostatin on sympathetic activity have b een examined in rats using electrophysiological techniques. Galanin, i n doses of 25-300 pmol, and enterostatin, in doses of 0.5-10 nmol, wer e injected into the third ventricle of anesthetized male Sprague-Dawle y rats in 1-mu l volumes. Galanin produced a dose-dependent suppressio n (ranging between 20 and 80%) of sympathetic firing rate of nerves in nervating interscapular brown adipose tissue. In rats fed a chow diet, injection of enterostatin produced only a transient 10% rise in firin g rate which returned to baseline within 10-15 min. In contrast, anima ls fed a high-fat diet showed a dose-dependent increase in firing rate lasting for 60 min. The results of this experiment are consistent wit h the hypothesis that food intake and sympathetic nervous system activ ity have a reciprocal relationship. The implications of this relations hip are discussed.