Digoxin potentiation of the norepinephrine response in vascular smooth muscle

1. 1. Cardiac glycosides, in concentrations insufficient to produce vasoconstriction alone, are capable of potentiating the vasoconstrictor response in vascular smooth muscle to α-adrenergic stimulation. 2. 2. The data presented here suggest that digoxin potentiates the response to norepinephrine in vascular smooth muscle by a mechanism other than an alteration in cellular membrane potential or a facilitated influx in extracellular calcium ion alone. 3. 3. It is suggested that the mechanism of this response may be related to an augmented release of intracellular calcium stores.