Signal Transduction Mechanisms
The regulation of cardiac and vascular function depends on various substances (e.g., neurotransmitters, circulating hormones, paracrine substances) signaling a cell to alter its function. Generally, 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 lead to changes, for example, in muscle contraction, the firing of cardiac pacemakers, or the conduction of electrical impulses in the the heart.
There are several major signal transduction mechanisms found in cells of the cardiovascular system, the most important being the G-protein, IP3, and cyclic GMP pathways. Click on the following links to read detailed descriptions of these mechanisms in cardiac cell and vascular smooth muscle cells: