CRH and the noradrenergic system mediate the antinociceptive effect of central interleukin-1α in the rat

After intracerebroventricular administration, both interleukin-1_α and corticotropin-releasing hormone increase nociceptive thresholds evaluated by the hot-plate test in the rat. Pretreatment with 6-hydroxydopamine or prazosin fully prevents the action of both substances. Moreover, the effect of interleukin-1_α is completely blocked by the intracerebroventricular administration of the corticotropin-releasing hormone antagonist α-helical CRH 9–41. Our results suggest an involvement of CRH and the noredrenergic system in the antinociceptive effect of central interleukin-1_α.