PERENNIAL RHINITIS SUBJECTS HAVE ALTERED VASCULAR, GLANDULAR, AND NEURAL RESPONSES TO BRADYKININ NASAL PROVOCATION

Background: Bradykinin (BK) is known to stimulate vascular permeability by direct actions on vascular B2 receptors, and may stimulate nociceptive sensory nerves that recruit parasympathetic reflexes which induces glandular secretion. Differences in these responses may occur in allergic rhinitis. Methods: The effects of bradykinin (BK) on nasal secretion in vivo were studied by unilateral BK nasal challenge in 8 normal subjects and 6 subjects with severe perennial allergic rhinitis. BK (0, 100, 1,000 nmol) were applied to one nostril (ipsilateral, IL) and saline lavage fluids collected separately from the IL and contralateral (CL) nostrils for analysis of total protein, albumin, glycoconjugates, and lysozyme. Results: In both groups, BK induced significant dose-dependent IL total protein and albumin secretion, but significantly more total protein and albumin were stimulated in normal than rhinitis subjects after 1,000 nmol BK. Glycoconjugate and lysozyme secretion was not significantly stimulated on either the IL or CL sides in normal subjects. However, in perennial allergic subjects, BK stimulated significant, dose-dependent glycoconjugate and lysozyme secretion on the IL side. Reflex effects were studied on the CL side. Normal subjects did not have significant CL glandular secretion. In contrast, rhinitis subjects secreted significantly higher amounts of total protein and glycoconjugate on the CL side after 1,000 nmol BK. There was no reflex-mediated albumin exudation in either group. Conclusions: These results indicate that in normal subjects BK stimulates predominantly vascular permeability, and that cholinergic reflexes do not significantly contribute to their BK-induced nasal secretion. In rhinitis subjects, BK again induced albumin exudation, but with less vascular permeability and greater glandular secretion than normal subjects on the challenged side. Only rhinitis subjects demonstrated significant contralateral reflex-mediated glandular secretion, and this response required the highest dose of BK. This suggests that BK is more adept at directly inducing vascular effects than glandular secretion of nociceptive nerve-parasympathetic reflexes. Alterations in BK-induced vascular permeability, glandular secretion, and neural reflexes occur in patients with severe perennial allergic rhinitis, changes suggestive of nasal hyperresponsiveness' to BK.