INHIBITION BY NOCICEPTIN OF NEUROGENIC INFLAMMATION AND THE RELEASE OF SP AND CGRP FROM SENSORY NERVE-TERMINALS

Pretreatment with the novel neuropeptide nociceptin (20 mu g kg(-1), i .p.) caused an inhibition of plasma extravasation evoked by antidromic stimulation of the saphenous nerve or by topical application of 1% mu stard oil on the skin of the acutely denervated hindleg of the rat. In contrast, it did not affect non-neurogenic inflammation evoked by s.c . injection of bradykinin after chronic denervation. Release of substa nce P (SP) and calcitonin gene-related peptide (CGRP) from rat isolate d tracheae in response to electrical held stimulation was diminished b y nociceptin (100 nM). It is concluded that nociceptin inhibits the re lease of sensory neuropeptides from terminals of nociceptive neurones.