Allergen-Induced Bronchoconstriction in Asthmatic Children (9)
In addition, BN52021 was less efficient in inhibiting the PAF-induced bronchoconstriction in patients than in normal subjects, especially at low concentration. Rubin et al also reported a greater decrease of FEVi at 1,000 mg/L of PAF in asthmatics (10 percent) than in normal subjects (5 percent), and the asthmatic responders were approximately four times more sensitive to PAF than the normal responders. The hyperresponsiveness of asthmatic airways to PAF may be due to the differences in the function and/or the number of PAF receptors or the activity of PAF acetylhydrolase. Cheap Diskus Advair
The mechanisms by which PAF induces bronchoconstriction are still unclear. In addition to a possible direct contractile effect, several lines of evidence indicate that PAF-induced bronchoconstriction may be a platelet-dependent inflammatory process: (1) the PAF-induced bronchoconstriction could be abrogated by prior depletion of circulating platelets by using an anti-platelet antiserum, and (2) histamine secretion from circulating platelets had been shown to be involved in PAF-induced bronchospasm in rabbits. However, it should be kept in mind that all of these experiments were done in animals rather than in humans.