Action of Catecholamines on the Smooth Muscle Cell Membrane

Abstract

At a previous symposium on drug action, entitled Adrenergic Mechanisms, the dual action of adrenaline was one of the problems discussed. The observations then available led to the idea (Bülbring, 1960) that adrenaline had two actions, one a direct action on the cell membrane and another action affecting the membrane only indirectly, the primary action being metabolic. The direct action on the membrane (α-action)—presumably an increase in permeability to one or several ions—would depolarize the membrane and make it more excitable. The metabolic action (ß-action) on the other hand, would affect the functional state of the cell by making more metabolic energy available. It was assumed that this energy could be used, not only for the contractile mechanism, but also for metabolic processes which stabilize the cell membrane, making it less excitable.