ABSTRACT
Ion channels generate and orchestrate the electrical signals that drive heart beat, muscle contraction, perception of sensory stimuli and thinking in the brain. As maeromolecular protein tunnels, ion channels span the plasma membrane’s lipid bilayer and allow for flow of the inorganic ions sodium, potassium, calcium, and chloride in and out of the cell at rates greater than 106 per second. This high rate is considered a diagnostic feature distinguishing channels from other ion transport devices such as the Na+/K+ pump. In contrast to the latter, ionic flux through chan nels does not require immediate delivery of metabolic energy because it is driven by electrochemical gradients [1,2].
