Effects of partial and complete vagal denervation on spontaneous ingestion and drinking induced with volemic and osmotic regulatory challenges

Publisher Website
Google Scholar
Abstract
The present study investigated the effects of unilateral right or left cervical vagotomy, selective subdiaphragmatic transection of the anterior vagal trunk, the posterior vagal trunk or the hepatic branch of the vagus, and the effects of total abdominal vagotomy with concomitant pyloroplasty on the regulation of spontaneous ingestive behavior and responsiveness to osmotic and volemic challenges. Total abdominal vagotomy with pyloroplasty somewhat reduced food intake, water consumption, and body weight measured ten weeks postsurgery. The other denervation procedures did not affect these parameters of spontaneous ingestive behavior. In additional tests given approximately two and four months postsurgery, rats that had undergone total abdominal vagotomy exhibited a significantly longer latency to drink and consumed less water than controls during the initial 0.5 hours after injection of hypertonic saline. These total abdominally vagotomized rats also exhibited significantly lower cumulative physiological saline intake in comparison to controls for 4, 8, and 16 hours after subcutaneous injection with polyethylene glycol, but not 2 or 24 hours postinjection. However, total abdominal vagotomy did not impair water drinking one, two, or four hours after injection with D,L‐isoproterenol (0.04–0.32 mg/kg body weight). The other denervation procedures did not alter drinking in response to isoproterenol or polyethylene glycol injections, and most of these groups exhibited normal latency and intake following injection of hypertonic saline. The hepatic vagotomy group, however, exhibited a shorter latency to drink in response to hypertonic saline injection than controls. The present results demonstrate that spontaneous food and water intake, body weight, and responsiveness to various volemic and osmotic regulatory challenges are clearly impaired only by the total abdominal vagotomy procedure.