beta1 - Adrenergic Receptors (NE)

Activation of adenylyl cyclase by agonists that bind to beta1-adrenergic receptors.
Binding to beta1-adrenoceptors stimulates adenylyl cyclase by activating the stimulatory G protein, Gs, which leads to the dissociation of its alpha subunit charged with GTP. This alpha subunit directly activates adenylyl cyclase, resulting in an increased rate of synthesis of cAMP. These catalytic units also phosphorylate the cAMP response element binding protein (CREB), which modifies gene expression.
beta1-adrenergic receptors cause actions in the heart in the following manner:

• Heart SA node: increase in heart rate.
• Heart AV node: increase in automaticity and conduction velocity
• Heart Atria and Ventricles: increase in contractility and conduction velocity
• Kidney: increased Renin Secretion

Adapted from Figure 9-2: StatRef Online Library: Basic and Clinical Pharmacology 8th ed. (2001)
by Michael Bolger, 8/24/04
Copyright(c) 2001 The McGraw Hill Companies, Inc. All rights reserved