Effects of ipratropium bromide on bradykinin nasal provocation in chronic allergic rhinitis

Bradykinin (BK) induces albumin exudation and glandular secretion in chronic allergic rhinitis subjects. Since bradykinin may stimulate nociceptive sensory nerves, neural reflex arcs could contribute to the secretion process. Six chronic allergic rhinitis subjects received 1000 nM bradykinin by unilateral nasal provocation using the method of Raphael et al. This dose induces optimal contralateral glandular secretion. Ipratropium bromide (80 micrograms) or saline were applied topically before the challenges. Total protein, albumin, glycoconjugate, and lysozyme were measured in lavage fluids. On the ipsilateral side, bradykinin induced significant total protein, glycoconjugate, and albumin secretion. None of these were affected by ipratropium. On the contralateral side, total protein and glycoconjugates were increased by bradykinin, while albumin and lysozyme were not significantly affected. Ipratropium bromide completely ablated total protein and glycoconjugate secretion on the contralateral side indicating that cholinergic reflexes mediated the glandular secretion. In chronic allergic rhinitis, bradykinin directly stimulated albumin secretion, but also stimulates nociceptive neuron--parasympathetic nerve reflexes to induce glandular secretion. The reflex loop was apparent on the contralateral side to the unilateral bradykinin challenge. This loop induced mucoglycoconjugate, but not serous cell, secretion in chronic allergic rhinitis subjects and can be inhibited by iptratropium bromide.