Adrenergic nervous system signaling, particularly via beta-adrenergic receptors and G-proteins, regulates cardiac myocyte apoptosis and may contribute to the development of myocardial failure.
Adrenergic nervous system activation, a hallmark of heart failure, regulates myocyte apoptosis primarily through beta-adrenergic receptor and G-protein signaling pathways.
Increased sympathetic nerve activity to the myocardium is a central feature in patients with heart failure. Norepinephrine, the primary transmitter of the sympathetic nervous system, signals via binding to alpha- and beta-adrenergic receptors (AR) that are coupled to G-proteins. Pharmacologic studies of cardiac myocytes in vitro demonstrate that beta-AR can stimulate apoptosis. Likewise, in transgenic mice overexpression of beta 1-AR or G alpha s is associated with myocyte apoptosis and the development of dilated cardiomyopathy. Whereas beta 1-AR stimulate apoptosis in vitro and in vivo, beta 2-AR may either stimulate or inhibit apoptosis and myocardial failure depending on the level of expression. Receptors coupling to Gi and Gq may also be able to mediate or modulate apoptosis and the development of myocardial failure, suggesting the potential for interactions between the beta-AR system and numerous remodeling stimuli that act through Gi or Gq signaling pathways. It appears likely that the mitogen-activated protein kinase superfamily plays a key role in mediating the actions of adrenergic pathways on myocyte apoptosis. These observations suggest that the adrenergic nervous system plays an important role in the regulation of myocyte apoptosis, and may thus contribute to the development of myocardial failure.
Krishna Singh (Tue,) conducted a review in Heart failure and myocardial apoptosis. Adrenergic pathway signaling was evaluated on Myocyte apoptosis and development of myocardial failure. Adrenergic nervous system signaling, particularly via beta-adrenergic receptors and G-proteins, regulates cardiac myocyte apoptosis and may contribute to the development of myocardial failure.