Hypertonic saline nasal provocation stimulates nociceptive nerves, substance P release, and glandular mucous exocytosis in normal humans.

Hypertonic saline (HTS) induces bronchoconstriction. Potential mechanisms were evaluated in a human nasal provocation model. Aliquots of normal saline (1 × NS, 100 μ l) and higher concentrations (3 × NS, 6 × NS, 12 × NS, 24 × NS) were sprayed into one nostril at 5-min intervals. Lavage fluids were collected from the ipsilateral and contralateral sides to determine the concentrations of specific mucus constituents. Nasal cavity air-space volume was assessed by acoustic rhinometry (AcRh). The distribution of substance-P-preferring neurokinin-1 (NK-1) receptor mRNA was assessed by in situ reverse transcriptase–polymerase chain reaction. Unilateral HTS induced unilateral dose-dependent increases in sensations of pain, blockage, and rhinorrhea, the weights of recovered lavage fluids, and concentrations of total protein, lactoferrin, mucoglycoprotein markers, and substance P. Contralateral, reflex-mediated effects were minor. There were no changes in IgG or AcRh measurements. NK-1 receptor mRNA was localized to...