CRH AND THE NORADRENERGIC SYSTEM MEDIATE THE ANTINOCICEPTIVE EFFECT OF CENTRAL INTERLEUKIN-1(ALPHA) IN THE RAT

After intracerebroventricular administration, both interleukin-1, and corticotropin-releasing hormone increase nociceptive thresholds evaluated by the hot-plate test in the rat. Pretreatment with 8-hydroxydopamine or prazosin fully prevents the action of both substances. Moreover, the effect of interleukin-1(alpha) is completely blocked by the intracerebroventricular administration of the corticotropin-releasing hormone antagonist alpha-helical CRH 9-41. Our results suggest an involvement of CRH and the noradrenergic system in the antinociceptive effect of central interleukin-1(alpha).