Intracerebroventricular administration of a specific IL-1 receptor antagonist blocks food and water intake suppression induced by interleukin-1 beta.

Intracerebroventricular (ICV) microinfusion of recombinant human interleukin-1 beta (rhIL-1 beta, 1.0 ng/rat) suppressed the short-term (2 h) food and water intakes in rats. ICV infusion of recombinant human IL-1 receptor antagonist (rhIL-1ra) had no effect on food or water intake. Concomitant ICV infusion of rhIL-1 beta (1.0 ng/rat) and increasing concentrations of rhIL-1ra (25 to 1000 ng/rat) resulted in a dose-dependent inhibition of the short-term food and water intake suppression induced by rhIL-1 beta. The highest doses of rhIL-1ra (500 and 1000 ng/rat) completely blocked the food and water intake suppression induced by rhIL-1 beta. This suggests specificity of IL-1 beta suppression of short-term feeding and drinking by a direct action in the central nervous system (CNS). This ability of rhIL-1ra may have potential therapeutic implications in acute and chronic pathological processes associated with increased levels of IL-1 and appetite suppression.