NITRIC-OXIDE REDUCES BODY-TEMPERATURE AND SYMPATHETIC INPUT TO BROWN ADIPOSE-TISSUE DURING PGE(1)-HYPERTHERMIA

The firing rate of the nerves innervating interscapular brown adipose tissue (IBAT) and IBAT and colonic temperatures (T-IBAT and T-c) were monitored in urethane-anaesthetized male Sprague-Dawley rats. These va riables were measured for 40 min before (baseline values) and 40 min a fter a 4 mu moles L-arginine (L-arg) or 400 nmoles nitroprusside (NP) injection in a lateral cerebral ventricle and an intracerebroventricul ar administration of 500 ng prostaglandin E(1) (PGE(1)). The same vari ables were monitored in other rats with L-arg or NP or PGE(1) administ ration alone. No drug was injected in control rats. The results show t hat L-arg or NP injection reduces the increases in firing rate, T-IBAT , T-c induced by PGE(1). These findings suggest that nitric oxide is i mportant in the control of thermogenic changes during the PGE(1) hyper thermia.