Calcium channel

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]

Overview

A Calcium channel is an ion channel which displays selective permeabiltiy to calcium ions. It is sometimes synonymous as voltage-dependent calcium channel, although there are also ligand-gated calcium channels.

Comparison tables

The following tables explain gating, gene, location and function of different types of calcium channels, both voltage and ligand-gated.

Voltage-gated

Main article: voltage-dependent calcium channel

Type	Gated by	Protein	Gene	Location	Function
L-type	high voltage	Cav1.1 Cav1.2 Cav1.3 Cav1.4	CACNA1S CACNA1C CACNA1D CACNA1F	Skeletal muscle, bone (osteoblasts), ventricular myocytes**, dendrites and dendritic spines of cortical neurones	SMC and cardiac muscle contraction . Responsible for prolonged action potential in cardiac muscle.
P-type/Q-type	high voltage	Cav2.1	CACNA1A	Purkinje neurons in the cerebellum / Cerebellar granule cells	neurotransmitter release
N-type	high voltage	Cav2.2	CACNA1B	Throughout the brain	neurotransmitter release
R-type	intermediate voltage	Cav2.3	CACNA1E	Cerebellar granule cells, other neurons	?
T-type	low voltage	Cav3.1 Cav3.2 Cav3.3	CACNA1G CACNA1H CACNA1I	neurons, cells that have pacemaker activity, bone (osteocytes)	Regular sinus rhythm

Ligand-gated

• the receptor-operated calcium channels (in vasoconstriction)
  • P2X receptor

Type	Gated by	Gene	Location	Function
IP3 receptor	IP3		ER/SR	Releases calcium from ER/SR in response to IP3 by e.g. GPCRs
Ryanodine receptor	dihydropyridine receptors in T-tubules		ER/SR	Calcium-induced calcium release in myocytes
Two-pore channel
Cation channels of sperm
store-operated channels	indirectly by ER/SR depletion of calcium		plasma membrane

Pharmacology

Calcium channel blockers are used to treat hypertension.

External links

• Calcium+Channels at the US National Library of Medicine Medical Subject Headings (MeSH)

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