Voltage-dependent calcium channel

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, etc.) with a permeability to the calcium ion Ca2+. These channels are slightly permeable to sodium ions, so they are also often called "Ca2+-Na+ channels", but their permeability to calcium is about 1000-fold greater than to sodium under normal physiological conditions.

Structure[edit | edit source]

VDCCs are formed as a complex of several different subunits: α1, α2δ, β1-4 and γ. The α1 subunit forms the ion conducting pore while the associated subunits have several functions including the regulation of gating and modulation of the channel's activity.

Types[edit | edit source]

There are several types of VDCCs, classified according to the voltage at which they activate:

L-type channels (Long-lasting)
P/Q-type channels (Purkinje / Quality)
N-type channels (Neural)
R-type channels (Residual)
T-type channels (Transient)

Function[edit | edit source]

VDCCs play a crucial role in both neurons and muscle cells. They are responsible for the influx of calcium ions into the cell, which initiates a series of events including muscle contraction, neurotransmitter release, gene expression, and cell death.

Clinical significance[edit | edit source]

Abnormalities in VDCC function can lead to a variety of diseases, such as hypertension, cardiac arrhythmia, and migraine. Certain drugs, like calcium channel blockers, are used to prevent the opening of these channels and thus treat these conditions.