Effect of inhaled substance P and neurokinin A on the airways of normal and asthmatic subjects.
The neuropeptides substance P and neurokinin A are present in sensory airway nerves. Their effect on airway calibre was compared in six healthy non-smoking subjects and six asthmatic subjects. On separate days increasing concentrations (from 10(-9) to 10(-6) mol/ml) of each neuropeptide were administered by nebuliser and the airway response measured as change in specific airway conductance (sGaw). Substance P and neurokinin A caused no change in sGaw in the healthy subjects. Inhalation of substance P up to the highest concentration of 10(-6) mol/ml caused no change in sGaw in the asthmatic subjects. Neurokinin A, however, caused bronchoconstriction with a mean fall in sGaw of 48% (SEM 12%) after 5 x 10(-7) mol/ml. The onset of bronchoconstriction was rapid, but sGaw had returned to baseline values within one hour in all but one patient.
D000280:Administration, Inhalation; D000293:Adolescent; D000328:Adult; D000403:Airway Resistance / Q000187:drug effects*; D001249:Asthma / Q000503:physiopathology*; D001985:Bronchial Provocation Tests; D004305:Dose-Response Relationship, Drug; D005260:Female; D005541:Forced Expiratory Volume; D006801:Humans; D008168:Lung / Q000503:physiopathology*; D008297:Male; D015288:Neurokinin A; D009479:Neuropeptides / Q000008:administration & dosage / Q000494:pharmacology; D011897:Random Allocation; D013373:Substance P / Q000008:administration & dosage / Q000494:pharmacology*
D009479:Neuropeptides; D013373:Substance P; D015288:Neurokinin A