Finding Channels [Membrane Biology]

October 2nd, 2015 by Catterall, W. A.

Voltage-gated ion channels are responsible for action potential generation in nerve and muscle and other excitable cells, and they participate in many forms of cellular regulation in other cell types. In excitable cells, action potentials are typically initiated by activation of voltage-gated sodium channels, which conduct sodium rapidly into the cell and depolarize the cell membrane potential. Depolarization activates voltage-gated calcium channels, which conduct calcium into the cell. Calcium entry sustains the depolarization of the cell membrane and generates intracellular calcium transients that initiate many intracellular events, including contraction, secretion, synaptic transmission, regulation of enzymes, and regulation of gene expression. Action potentials are terminated by activation of voltage-gated potassium channels, which conduct potassium out of the cell, repolarize the membrane, and contribute to setting the resting membrane potential.