VAGAL AND SPLANCHNIC AFFERENTS ARE NOT NECESSARY FOR THE ANOREXIA PRODUCED BY PERIPHERAL IL-1-BETA, LPS, AND MDP

We investigated the extrinsic sic gut neural mediation of the suppress ion of food intake in male Sprague-Dawley rats induced by peripheral i ntraperitoneal administration of 2 mu g/kg interleukin-1 beta (IL-1 be ta), 100 mu g/kg bacterial lipopolysaccharide (LPS), and 2 mg/kg muram yl dipeptide (MDP). Food intake during the first 3 and 6 h of the dark cycle was measured in rats with subdiaphragmatic vagal deafferentatio n (n = 9), celiac superior mesenteric ganglionectomy(n = 9), combined vagotomy and ganglionectomy (n = 9), and sham deafferentation (n = 9). IL-1 beta, LPS, and MDP suppressed food intake at 3 and 6 h in all su rgical groups. The results demonstrate that neither vagal nor nonvagal afferent nerves from the upper gut are necessary for the feeding-supp ressive effects of intraperitoneal IL-1 beta, LPS, or MDP in the rat a nd suggest that peripheral administration of immunomodulators produces anorexia via a humoral pathway.