Beta-adrenergic receptors in congestive heart failure: present knowledge and future directions.

In recent years substantial information has become available on the function and regulation of beta-adrenergic receptors in experimental model systems and in the human heart. Beta-Adrenergic receptors mediate the positive inotropic and chronotropic effects of the sympathetic neurotransmitter norepinephrine in the heart. They can be altered in various disease states including congestive heart failure. In order to enhance understanding of beta-adrenergic receptor regulation in heart failure, we here review the present knowledge and the open question in three areas: (1) the differential role of beta 1- and beta 2-adrenergic receptors: (2) regulation of the number of cardiac beta-adrenergic receptors by drugs and disease states: and (3) regulation of the responsiveness of cardiac beta-adrenergic receptors.