Effect of guanethidine sympathectomy on intake and body weight of intact and LHA-lesioned rats

The present study investigated the role of direct sympathetic nervous system innervation of the viscera in the reduced body weight levels maintained by animals bearing lesions of the lateral hypothalamic area (LHA). Adult, male rats with, and without, electrolytic lesions of the (LHA) were treated with guanethidine sulphate (25 mg/kg IP daily for 6 weeks) to produce destruction of the peripheral sympathetic nervous system. LHA-lesioned rats displayed the expected reduced body weight compared to intact rats. Sympathectomy in lesioned rats resulted in an identical pattern of effects to that seen in intact rats. Transitory reductions in intake were effected and weight was significantly depressed by one week of guanethidine treatment. However, weight had recovered to control levels in both intact and lesioned drug-treated groups by the end of the experiment. The reduced body weight level maintained by LHA-lesioned rats was not altered by guanethidine sympathectomy. The major conclusions are (1) the reduced body weights maintained following LHA lesions are not dependent upon an intact sympathetic nervous innervation of visceral organs, and (2) peripheral sympathectomy in intact adult rats has no chronic effects on either body weight or food and water intake.