Voltage-gated calcium channel

Voltage-gated calcium channel =
Identifiers
Symbol	VGCC
Pfam	PF08473
OPM superfamily	8
OPM protein	8epl
Membranome	214
Available protein structures: PDB   5GJV, 7MIY, 7WLI, 8FD7, 8X90 PF08473 (ECOD; PDBsum)   AlphaFold PF08473

Voltage-gated calcium channels (VGCCs), also known as voltage-dependent calcium channels (VDCCs), are a group of voltage-gated ion channels found in the membrane of excitable cells (e.g. muscle, glial cells, neurons) which are permeable to calcium ion Ca²⁺. Since these channels are slightly permeable to sodium ions, they are also called Ca²⁺–Na⁺ channels, but their permeability to calcium is about 1000-fold greater than to sodium under normal physiological conditions.

At physiologic or resting membrane potential, VGCCs are normally closed. They are activated (i.e.: opened) at depolarized membrane potentials and this is the source of the "voltage-gated" epithet. The concentration of calcium (Ca²⁺ ions) is normally several thousand times higher outside the cell than inside. Activation of particular VGCCs allows a Ca²⁺ influx into the cell, which, depending on the cell type, results in activation of calcium-sensitive potassium channels, muscular contraction, excitation of neurons, up-regulation of gene expression, or release of hormones or neurotransmitters.

VGCCs have been immunolocalized in the zona glomerulosa of normal and hyperplastic human adrenal, as well as in aldosterone-producing adenomas (APA), and in the latter T-type VGCCs correlated with plasma aldosterone levels of patients. Excessive activation of VGCCs is a major component of excitotoxicity, as severely elevated levels of intracellular calcium activates enzymes which, at high enough levels, can degrade essential cellular structures.