Roles of central interleukin-1 on stress-induced-hypertension and footshock-induced-analgesia in rats

Central interleukin-1 (IL-1) plays an important role in mediating the neura l, endocrine, and behavioral responses to stressors. Here we tested whether central IL-1 is involved in stress-induced hypertension or footshock (FS)- induced-analgesia. We observed that: (1) intracerebral ventricular injectio n of (ICV) IL-1 beta induced pressor responses; (2) hypertension induced by IL-1 was blocked by ICV an IL-1 antagonist, IL-1 ra; (3) ICV IL-1 ra atten uated the pressor response induced by FS but intravenous injection of IL-1r a did not significantly reduce this response; (4) the hypertensive response to conditioned fear stimuli was reversed by ICV IL-1ra; (5) FS-induced-ana lgesia was attenuated by ICV IL-1ra and this effect disappeared 15 min afte r ICV IL-1 ra. These results suggest that both the pressor response to FS o r conditioned fear stimuli and short lasting analgesia induced by FS are me diated by central IL-1. (C) 2001 Elsevier Science Ireland Ltd. All rights r eserved.