Signal Transduction Mechanisms
The regulation of cardiac and vascular function depends on various substances (e.g., neurotransmitters, circulating hormones, paracrine substances) signaling cells to alter their function. This is accomplished through the binding of a chemical entity (ligand) to a receptor, most commonly located on the cell membrane. When a ligand binds to a receptor, the receptor signals biochemical changes within the cell that can alter muscle contraction, firing of cardiac pacemakers, or the conduction of electrical impulses in the heart.
There are several major signal transduction mechanisms found in cells of the cardiovascular system, the most important being the G-protein-mediated changes in cyclic AMP and inositol triphosphate (IP3), and cyclic GMP pathways. Click on the following links to read detailed descriptions of these mechanisms in cardiac cells and vascular smooth muscle cells: