|Anna Dor, Jerzy Liebhart, Ewa Liebhart, Alina Orda, Józef Małolepszy|
Although bronchial asthma is commonly accepted as an inflammatory disease of the airways, neural mechanisms seem to contribute to its symptomatology. Neuropeptides such as substance P (SP) released from sensory nerves have proinflammatory properties and induce smooth muscle contraction, as well as microvascular leakage and increased mucus production. Conversely, vasoconstrictor response is mediated by the release of neuropeptide Y (NPY) from sympathetic nerves.
To investigate the role of nonadrenergic, noncholinergic pathway in the pathogenesis of exercise induced bronchoconstriction, we performed exercise test in 39 subjects with bronchial asthma. The patients were examined according to a standardised protocol with 8 minutes of cycling at 80% of the VO2 max. A postexercise bronchospasm was considered to have occurred if FEV1 fell ł15% with reference to baseline value. Based on the applied criteria, exercise-induced asthma (EIA) was diagnosed in 17 patients; the results of the test were negative in the remaining 22 asthmatics. Both groups were homogeneous with regard to age and baseline spirometric values. Plasma concentrations of SP and NPY were determined by radioimmunoassay (DRG, Germany) in blood samples taken before and at 1, 15 and 30 minutes after completion of the exercise.
Preexercise SP as well as NPY plasma concentrations did not differ significantly between groups of patients with and without exercise - induced bronchoconstriction (p=0.57 and 0.12 respectively). Further, no significant post exercise variability, tested by use of analysis of variance (ANOVA), was found for both neuropeptides examined in the group of patients with (p=0.70 and 0.53 respectively) as well as in those without exercise induced bronchoconstriction (p=0.51 and 0.68 respectively).
These results may suggest that substance P and neuropeptyde Y do not contribute to exercise-induced bronchoconstriction in asthmatic patients.
Alergia Astma Immunologia, 2001, 6(4), 201-204
keywords: astma oskrzelowa, neuromediatory, powysiłkowy bronchospazm, bronchial asthma, neuropeptides, exercised-induced asthma
pages: from 201 to 204
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