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Responses of plasma vasoactive intestinal polypeptide to methacholine and exercise loading in children and
T Ohzeki1, N Ishitani, K Hanaki
1Department of Pediatrics, Faculty of Medicine, Tottori University, Yonago, Japan.
Abstract:
Responses of plasma vasoactive intestinal polypeptide (VIP) to methacholine inhalation and to exercise loading were studied in asthmatic patients to clarify a significant role of the peptide. The mean of basal VIP in asthmatics was not significantly different from the normals. The levels were increased after FEV (1.0) (forced expiratory volume in a second) decreased to 80% of the baseline following methacholine inhalation and were returned to values similar to the baseline when FEV (1.0) recovered to 100%. Thirty minutes after the exercise, mean VIP was significantly lower in patients with the lowest FEV (1.0). These results suggest that VIPergic system contributes, at least partly, to relax constricted bronchioles in some patients with bronchial asthma.