LATERAL HYPOTHALAMIC-LESION INDUCES SYMPATHETIC-STIMULATION AND HYPERTHERMIA BY ACTIVATING SYNTHESIS OF CEREBRAL PROSTAGLANDINS

This experiment tests the effect of intracerebroventricular (icv) inje ction of lysine acetylsalicylate on the sympathetic and thermogenic ch anges induced by lesion of the lateral hypothalamus (LH). The firing r ate of the nerves innervating interscapular brown adipose tissue (IBAT ), along with IBAT and colonic temperatures (T-IBAT and T-C) were moni tored in urethane-anaesthetized male Sprague-Dawley rats lesioned in t he LH. These variables were measured before and after an icy injection of 1 mg lysine acetylsalicylate. The same variables were also monitor ed in: a) lesioned rats with icy administration of saline; b) sham-les ioned animals with icy injection of lysine acetylsalicylate; c) sham-l esioned rats with icy injection of saline. In an additional experiment , the same variables were monitored after an icy injection of lysine a cetylsalicilate or saline in rats with LH lesion performed 48 h before the icy injection. The results show that lysine acetylsalicylate inje ction reduces the increases in firing rate, T-IBAT, and T-C induced by LH lesion. These findings suggest that cerebral prostaglandin synthes is plays a key role in the sympathetic and thermogenic changes followi ng LH lesion.