MODIFICATION OF INDUCED AIRWAY CONSTRICTION IN HEALTHY-SUBJECTS

  • 1 January 1979
    • journal article
    • research article
    • Vol. 43  (3) , 135-143
Abstract
Unlike asthmatics, healthy persons are relatively unresponsive to airway constrictors. By using partial expiratory flow-volume (PEFV) curves, healthy subjects demonstrated dose-related decreases in flow rates following challenge with histamine and methacholine aerosols. With the use of semilogarithmic dose-response curves 80 mg oral propranolol augmented, but oral pretreatment with 400 mg W1029A (an experimental bronchodilator) decreased, histamine and methacholine-induced airway constriction. Orally administered aminophylline (300 mg) failed to modify the airway constrictor effects of histamine and methacholine. Variation was noted in induced airway constriction in healthy subjects with decreases in flow rates being greater in the morning than in the afternoon. Apparently propranolol augments whereas theophylline fails to prevent nonspecific induced airway constriction in healthy subjects. The bronchodilator action of theophylline may be unrelated to its phosphodiesterase inhibitory activity, and control of volume history, by use of partial expiratory flow-volume curves, is useful in quantitying pharmacologic protection and augmentation of nonspecific induced airway constriction in healthy subjects. Induced airway constriction in healthy subjects may also be dependent upon the effects of diurnal variation.