Noradrenaline release in hypothalamus and ACTH secretion induced by central interleukin-1beta.

Abstract

The effect of interleukin-1beta (IL-1beta, 10 ng per 5 mu l i.c.v.) on noradrenaline release in the hypothalamus of freely moving rats and on plasma ACTH levels has been studied, respectively by intracerebral microdialysis and radioimmunoassay. IL-1beta induced an early increase in noradrenaline (NA) release in the paraventricular nucleus (PVN) followed by a second long-lasting enhancement starting from 80 min, with a maximum at 140 min (187 +/- 14%). Heat-denatured IL-1beta induced only the early increase without any other change at later times. IL-1beta did not significantly affect NA release in the area surrounding the PVN at any time. IL-1beta increased ACTH levels at 2 and 3 h. Indomethacin (10 mg kg(-1), i.p.) prevented the noradrenergic and ACTH responses. The NA system in the PVN plays a part in the mechanism controlling the ACTH response induced by IL-1.