[Neuropeptides of the nasal innervation and allergic rhinitis]

In the last decade, several neuropeptides have been localized in sensory, sympathetic and parasympathetic neurons of the upper and lower airways in animals and man. Tachykinins are sensory neuropeptides: after nasal allergen challenge in patients with allergic rhinitis, substance P is locally released and induces nasal obstruction. Like neurokinin A, another tachykinin of sensory C fibers, substance P induces an increase in vascular permeability and a recruitment of inflammatory cells. Thus, tachykinins partially mimic nasal response to antigen. Calcitonin gene-related peptide (CGRP) is another sensory neuropeptide and vasoactive intestinal peptide (VIP) is a neuropeptide localized to parasympathetic fibers. The distributions of CGRP and VIP fibers and of their binding sites, as well as their physiological effects described in other tissues, are consistent with a vasodilator effect. On the other hand, neuropeptide Y (NPY), a sympathetic neuropeptide, would seem to be a potent vasoconstrictor. Thus, nasal neuropeptides, and above all sensory neuropeptides, could play a role in the pathophysiology of allergic rhinitis.