Abstract
Eight normal male subjects participated in this study. Neurokinin A (NKA, 128μg), one of the nonadrenergic and noncholinergic neuropeptides, or physiological saline solution as a control was administered to nasal mucosa by jet nebulizer. The nasal mucosa was treated with thiorphan (2.5 mg), a neutral endopeptidase inhibitor, 10 minutes prior to NKA or saline administration. Ten minutes after NKA or saline challenge, dose responses to histamine were examined.
There was no significant difference in the histamine concentration that initially caused sneeze or watery rhinorrhea between NKA and saline administrations. NKA did not change the nasal patency evaluated by acoustic rhinometer. Results suggest that NKA does not induce hyperresponsiveness to histamine in normal human nose.
