Effects of inhaled platelet activating factor on pulmonary function and bronchial responsiveness in man

Platelet activating factor (PAF), a phospholipid inflammatory mediator, was given as an aerosol to eight normal subjects. PAF caused a dose-dependent bronchoconstriction in all subjects. This did not correlate well with responsiveness to methacholine. Some subjects showed tachyphylaxis to PAF-induce...

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Bibliographic Details
Published inThe Lancet (British edition) Vol. 2; no. 8500; p. 189
Main Authors Cuss, F M, Dixon, C M, Barnes, P J
Format Journal Article
LanguageEnglish
Published England 26.07.1986
Subjects
Adult
Aerosols
Bronchi - drug effects
Bronchi - physiology
Clinical Trials as Topic
Dose-Response Relationship, Drug
Double-Blind Method
Drug Synergism
Heart Rate - drug effects
Humans
Lung - drug effects
Lung - physiology
Lung Volume Measurements
Male
Methacholine Compounds - administration & dosage
Methacholine Compounds - pharmacology
Platelet Activating Factor
Random Allocation
Time Factors
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Summary:Platelet activating factor (PAF), a phospholipid inflammatory mediator, was given as an aerosol to eight normal subjects. PAF caused a dose-dependent bronchoconstriction in all subjects. This did not correlate well with responsiveness to methacholine. Some subjects showed tachyphylaxis to PAF-induced bronchoconstriction. No subject had a late bronchoconstriction response. Transient facial flushing and an increase in heart rate (mean 7 beats/min) occurred but there was no consistent change in blood pressure. Lyso-PAF, the inactive precursor and major metabolite of PAF, had no effect on pulmonary or cardiovascular responses. Six of the subjects took part in a double-blind, randomised, placebo-controlled, crossover study in which bronchial responsiveness to methacholine was measured over the 3 days after administration of PAF or lyso-PAF. PAF had a greater effect in raising responsiveness (p less than 0.01). Its maximum effect occurred at 3 days and returned to baseline in 1 to 4 weeks. PAF may contribute to the pathogenesis of bronchial hyperresponsiveness, which is the most characteristic abnormality in asthma.
ISSN:0140-6736