[The modulator effect of bradykinin with respect to tracheobronchial clearance in healthy subjects]

Abstract

Bradykinin (Bk), a vasoactive nonapeptide which has been proposed as mediator in the pathogenesis of bronchial asthma, is a potent secretagogue in canine airways and in human nasal mucosa in vivo. A study was carried out in order to evaluate the effect of inhaled Bk on tracheobronchial clearance (TBC), measured by a radioaerosol technique in 10 healthy volunteers. Subjects inhaled Bk (8 mg/mL) or vehicle placebo on two occasions, at least 2 weeks apart, in a double blind and randomized fashion 30 min after radioaerosol inhalation. TBC, expressed as the area under the tracheobronchial radioaerosol retention curve calculated for the first 6 hours (AUC 0-6h), was enhanced in 9 of 10 subjects following inhaled Bk when compared to placebo. The mean values for AUC 0-6h were significantly reduced from 132%.h to 92%.h (p < 0.001) with placebo and Bk respectively. We conclude that Bk has a marked effect on tracheobronchial clearance in normal human airways.