Decreased neuropeptide release may play a role in the pathogenesis of nasal polyps

In this in vivo prospective, controlled study, we have examined the capsaic in-induced levels and secretion patterns of the colocalized neuropeptides s ubstance P calcitonin gene-related peptide (CGRP), and neurokinin A in nasa l secretions of subjects with nasal polyps, and we compared these with secr etion patterns from healthy subjects and from subjects with allergic rhinit is. Capsaicin was used to elicit neuropeptide release. The neuropeptide lev els were measured by an ELISA technique. For substance P subjects with nasa l polyps responded very poorly to capsaicin stimulation. The atopic group w as more reactive to capsaicin stimulation than control subjects. For CGRP t he increase was immediate in all groups. Atopic subjects and subjects with polyps had a less pronounced but sustained response to capsaicin stimulatio n. CGRP levels in atopic subjects and those with polyps were restored rapid ly. Atopic subjects had higher neurokinin A levels with an immediate and su stained response to capsaicin, Control subjects had higher levels than thos e with polyps, but both groups were nonresponsive to capsaicin stimulation.