Central effects of interleukin-1 on blood pressure, thermogenesis, and the release of vasopressin, ACTH, and atrial natriuretic peptide.

Abstract

To assess the central role of interleukin 1-beta (IL-1 beta) in the release of ACTH, vasopressin (AVP) and atrial natriuretic peptide (ANP) and in the regulation of blood pressure and thermogenesis, 3 ng (0.173 pM) x 100-1 x BW-1 (LIL), 30 ng (1.73 pM) x 100g-1 x BW-1 (MIL), and 150 ng (8.63 pM) x 100g-1 x BW-1 (HIL) of human IL-1 beta dissolved in sterile saline were injected intracerebroventricularly to conscious rats. In the control rats, saline alone (5 microliters) was administered. In three other groups, rats were pretreated with indomethacin, a cyclooxygenase inhibitor, given i.v. (1 mg x 100g-1 x BW-1); medium and high doses of IL-1 beta or its vehicle were given. In the LIL group, IL-1 beta increased blood pressure, body temperature and plasma AVP and ANP without any changes in heart rate (HR) and plasma ACTH. In the MIL group, plasma ACTH was increased, and changes in the other parameters were similar to those in the LIL group. In the HIL group, however, the pressor and thermogenetic responses were attenuated; plasma AVP, ACTH, and ANP were increased; and HR was unchanged. In the control (CON) group, none of these parameters was changed throughout the studies. Indomethacin abolished the AVP and ACTH responses to IL-1 beta, but potentiated the pressor and hypothermic responses and increased plasma ANP. These data suggest that the actions of IL-1 beta on AVP and ACTH release and thermogenesis, but not on blood pressure and the release of ANP, are modulated by the stimulated central production of prostaglandins.