Abstract
Summary: The bronchial smooth muscle is described and its autonomic innervation discussed. The effect of certain physiological substances on the smooth muscle is discussed and also the consequence of blockade of the alpha receptors of the sympathetic nervous system. Indoramin, a powerful alpha blocker is also antihistaminic and this drug has been used therapeutically in the treatment of some asthmatics. Prostaglandin F2 beta has not yet been applied in human subjects.