Ca2+ channels can be found in the plasma membrane of excitable cells such as neurons and myocytes. They open in response to cell depolarization, and the influx of Ca2+ ions into the cell can trigger a variety of intracellular events, including neurotransmitter release, secretion of hormones such as insulin, gene expression, and muscle contraction. Ca2+ channels can be gated by either voltage or ligands, and it is common to find several different types of Ca2+ channels on most cells.
