The effect of alpha-adrenoreceptor stimulation on the airways of normal and asthmatic man.

1. The bronchial response to alpha-adrenoreceptor stimulation has been investigated in normal and asthmatic subjects with a specific alpha-receptor agonist, methoxamine hydrochloride, after atropine and beta-adrenergic blockade. 2. No significant changes in forced expiratory volume in 1 s (FEV1.0) were seen in normal subjects. 3. Methoxamine inhalation caused mild symptomatic wheezing and significant falls in FEV1.0 in asthmatic subjects. No change in FEV1.0 occurred after inhalation of distilled water as control. 4. It therefore appears that methoxamine causes bronchoconstriction in asthmatic subjects through its alpha-adrenergic-stimulating properties, since we were not able to detect any beta-receptor-blocking activity of methoxamine on the airways.