Molecular mechanisms of adrenergic stimulation in the heart

Increased cardiac output in response to beta-adrenergic receptor stimulation is achieved by rapid alteration of the activity of cardiac ion channels, pumps, and exchangers. Over the past decade, the discovery of macromolecular complexes, which include the ion channels and pumps and the kinases that control their level of phosphorylation, has led to an increased understanding of the molecular mechanisms behind the cardiac adrenergic response. The increased understanding has led to the discovery of a new long QT gene encoding an accessory protein in one of these macromolecular complexes. This article briefly reviews the major components of the beta-adrenergic pathway in the heart and discusses the direction of current and future research.