Calcitonin gene-related peptide nasal provocation in humans

Trigeminal sensory nerves release neurotransmitters such as calcitonin gene-related peptide (CGRP), substance P, and others in human nasal mucosa. The effects of CGRP on nasal secretion were tested in humans in vivo by applying CGRP directly to nasal mucosa and then lavaging the nostrils ten minutes later. Concentrations of total protein, albumin, lysozyme, and orcinol-reactive mucoglycoconjugates were measured in lavage fluid. Calcitonin gene-related peptide (0.1 to 100 micrograms) did not stimulate secretion of any of these markers indicating that CGRP had no effect on glandular secretion or albumin exudation in vivo. These findings indicate that CGRP did not stimulate glands or endothelial cells of the vessels that regulate plasma extravasation. These data are consistent with previous studies that demonstrate 125I-CGRP binding sites on arterial vessels without detecting sites on glands or epithelium, the absence of effects of CGRP on glandular secretion from human nasal mucosal explants in vitro, and the apparently minor magnitude of sensory nerve axon responses in humans in vivo.