Central alpha 2-adrenoceptors mediate the inhibitory effect of lipopolysaccharide on sodium appetite independently from systemic inhibitory factors in rats

Abstract

Lipopolysaccharide (LPS) injected ip reduces sodium appetite in rats. In the present work we investigated a role for systemic inhibitory factors and alpha2-adrenoceptors on the effect of LPS on a sodium appetite test. Adult male rats (n=5–7/group) were depleted of sodium by a combination of the natriuretic furosemide sc plus 24h removal of ambient sodium to produce sodium appetite. LPS (2mg/kg) vs. saline ip increased the stomach liquid content (an index of gastric emptying and early pre-systemic gastrointestinal inhibitory signals) 5min after an intragastric load of 3ml of 0.3M NaCl given by gavage (4.4±0.4 vs.