Interleukin-1beta causes a biphasic response in neurons of rat major pelvic ganglia

Abstract

The effect of interleukin-1beta (IL-1beta) on peripheral autonomic neurons was examined with intracellular microelectrodes, in vitro. Recombinant human IL-1beta (6-300 pM) produced a depolarization, associated with decrease in input resistance, followed by a hyperpolarization, associated with increase in input resistance, in neurons of rat major pelvic ganglia (MPG). IL-1beta 163-171 (10-100 pM), the active domain of human IL-1beta, also produced a biphasic response. The IL-1beta-induced responses reversed polarity at the equilibrium potential for Cl-. The IL-1beta-induced responses were blocked by picrotoxin (100 microM) but not by bicuculline (20 microM). Imidazole-4-acetic acid (14AA, 100 microM), a GABA(C) receptor antagonist, reduced the IL-1beta-induced responses. The results suggest that the IL-1beta-induced biphasic response is mediated through GABA(C) receptors in rat MPG neurons.