Beta-adrenergic receptors and responses in the heart.

This article summarizes some essential steps leading to one of the most prominent beta-adrenergic effects on the heart, the increase in force of contraction. Binding of beta-adrenergic agonists and antagonists, activation of the enzyme adenylate cyclase by agonist binding, increase in membrane permeability to calcium ions, possibly via cyclic AMP, and increase in force of contraction and its relation to enhanced calcium influx are briefly discussed.