The influence of pretreatment with prostaglandin F2 alpha on bronchial sensitivity to inhaled histamine and methacholine in normal subjects.

The effect of pretreatment with prostaglandin F2 alpha (PGF2 alpha) on the bronchial sensitivity to histamine and methacholine has been studied in three groups of six normal subjects, and compared with the effect of citric acid aerosol as a non-specific stimulant of bronchial irritant receptors. Aerosols were generated by Wright's nebulizer and dose-response curves to histamine and methacholine constructed following preadministration of saline, prostaglandin F2 alpha or citric acid. Following prostaglandin F2 alpha pretreatment, the PC20 histamine fell from 12.9 mg/ml to 3.4 mg/ml (P less than 0.01), but the PC20 methacholine was unchanged. Citric acid was without effect. The results indicate that prostaglandin F2 alpha can increase bronchial sensitivity to inhaled histamine, possibly via a direct effect on the airway smooth muscle.