EFFECTS OF SYSTEMIC INTERLEUKIN-1-BETA ADMINISTRATION ON DAILY DRINKING AND RENAL EXCRETORY FUNCTION IN CONSCIOUS RATS

To elucidate the roles of interleukin-1 beta (IL-1 beta), a cytokine w ith several diverse actions, in the control of body fluid balance, its effects on daily drinking behavior and renal excretory function were examined in conscious rats. Administration of IL-1 beta (4 mu g/kg, IP ) resulted in the suppression of both daily drinking and food intake a nd a decrease in daily urinary sodium and potassium excretion, but had no effect on urine volume. The IL-1 beta-induced decrease in sodium e xcretion was abolished in renal-denervated rats. Kainic acid was then injected into the anteroventral third ventricle region, including the organum vasculosum of the lamina terminalis, to examine whether neuron s in this region are involved in the IL-1 beta-induced responses; the effects on daily drinking and urinary sodium and potassium excretion w ere abolished, whereas the effects on food intake, although attenuated , were still present. In contrast, electrical lesion of the subfornica l organ did not affect the IL-1 beta-induced responses. Thus, IL-1 bet a seems exert its effects on body fluid balance at several distinct si tes in the central nervous system. (C) 1997 Elsevier Science Inc.