Recombinant human interleukin-1 β alters the activity of preoptic thermosensitive neurons in vitro

Abstract

Effects of recombinant human interleukin-1 β (rhIL-1 β) on the single activity of thermosensitive and thermally insensitive neurons in the preoptic and anterior hypothalamus (PO/AH) were investigated in the rat's brain tissue slices. RhIL-1 β (2.8 × 10 −9 − 1.2 × 10 −8M) decreased the activity in 19 of 27 warm-sensitive neurons and excited 2 of 3 cold-sensitive neurons, but had no effect on the majority (22 of 32) of thermally insensitive neurons. The neuronal responses to local rhIL-1 β could be observed in a Ca 2+ free/high Mg 2+ solution, suggesting the postsynaptic actions of rhIL-1 β. The actions of rhIL-1 β on thermosensitive neurons were blocked or attenuated by concurrent application of sodium salicylate, but not by aloxone. The results suggest that centrally formed IL-1 β may induce fever by its actions on PO/AH thermosensitive neurons, which do not involve the opioid receptor mechanisms.