Background: Seasonal allergic rhinitic (SAR) subjects are more physiologically reactive to airborne irritants than non-rhinitic (NR) subjects; however the mechanism underlying this difference is unclear.
Objective: We sought to determine whether irritant-induced nasal airflow limitation involves neuropeptide release into nasal lining fluid, and if so, whether such release occurs differentially by rhinitic status.
Methods: Eight SAR and 8 NR subjects were exposed to 1.0 ppm chlorine and filtered air in random order during separate visits; exposures were via nasal mask and lasted 15 min. Rhinomanometry was performed before, immediately post-, and 15 min post-exposure. Following a minimum of 2 weeks' time, exposures and symptom reporting were repeated with nasal lavage pre- and post-exposure. Neuropeptides (substance P, cacitonin gene-related protein, vasoactive intestinal peptide, and neuropeptide Y) as well as markers of plasma leakage (albumin and urea) and glandular secretion (lysozyme and 7F10-mucin) were measured using standard methods.
Results: Cl(2) provocation significantly increased nasal airway resistance in SAR but not NR subjects (p<0.05). Neuropeptide levels in nasal lavage fluid, on the other hand, were unaffected, with the exception of a paradoxical increase in vasoactive intestinal peptide in non-rhinitic controls post-Cl(2) provocation.
Conclusions: Irritant-induced nasal airflow limitation is more pronounced among SAR than NR subjects. We could not, however, demonstrate a role for neuropeptide release in the nasal congestive response of SAR subjects.