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Calcium channel

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.

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1 Comparison tables
- 1.1 Voltage-gated
- 1.2 Ligand-gated
2 Pharmacology
3 References

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	Ca_v1.1 Ca_v1.2 Ca_v1.3 Ca_v1.4	CACNA1S CACNA1C CACNA1D CACNA1F	Skeletal muscle, bone (osteoblasts), ventricular myocytes**, dendrites and dendritic spines of cortical neurones	SMC and cardiac muscle contraction ^[1]. Responsible for prolonged action potential in cardiac muscle.
P-type/Q-type	high voltage	Ca_v2.1	CACNA1A	Purkinje neurons in the cerebellum / Cerebellar granule cells	neurotransmitter release ^[1]
N-type	high voltage	Ca_v2.2	CACNA1B	Throughout the brain	neurotransmitter release ^[1]
R-type	intermediate voltage	Ca_v2.3	CACNA1E	Cerebellar granule cells, other neurons	?^[1]
T-type	low voltage	Ca_v3.1 Ca_v3.2 Ca_v3.3	CACNA1G CACNA1H CACNA1I	neurons, cells that have pacemaker activity, bone (osteocytes)	Regular sinus rhythm^[1]

Ligand-gated

the receptor-operated calcium channels (in vasoconstriction)
- P2X receptor ^[2]

Type	Gated by	Gene	Location	Function
IP₃ receptor	IP₃		ER/SR	Releases calcium from ER/SR in response to IP₃ by e.g. GPCRs ^[1]
Ryanodine receptor	dihydropyridine receptors in T-tubules		ER/SR	Calcium-induced calcium release in myocytes ^[1]
Two-pore channel
Cation channels of sperm
store-operated channels	indirectly by ER/SR depletion of calcium^[1]		plasma membrane

Pharmacology

Calcium channel blockers are used to treat hypertension.

References

^ ^a ^b ^c ^d ^e ^f ^g ^h Rang, H. P. (2003). Pharmacology. Edinburgh: Churchill Livingstone. ISBN 0-443-07145-4. Page 53
^ Walter F., PhD. Boron. Medical Physiology: A Cellular And Molecular Approaoch. Elsevier/Saunders. ISBN 1-4160-2328-3. Page 479

v • d • e Membrane transport protein: ion channels
Ca²⁺: Calcium channel	Voltage-dependent calcium channel (L-type/Ca_vα(1.1, 1.2, 1.3, 1.4), N-type, P-type/Ca_vα(2.1), Q-type, R-type, T-type, β-subunits (β1, β2, β4), γ-subunits (γ2) • Inositol triphosphate receptor • Ryanodine receptor • Cation channels of sperm • Two-pore channel
Na⁺: Sodium channel	Na_vα (1.1, 1.2, 1.4, 1.5, 1.7, 1.9) • Na_vβ (1, 3, 4) • Epithelial sodium channel
K⁺: Potassium channel	Voltage-gated (K_vα (1.1, 1.2, 1.3, 1.4, 1.5, 2.1, 4.2, 4.3, 7.1, 7.2, 7.3, 7.4, 10.1, 11.1/hERG) • K_vβ (1, 2), Shaker gene, KCNE1) • Calcium-activated (BK channel, SK channel, SK3) • Inward-rectifier K_ir (1.1, 2.1, 2.2, 2.3, 3.1, 3.2, 3.4, 4.1, 4.2, 6.1, 6.2)) • Tandem pore domain K2P (1, 2, 3, 4, 6, 9)
Cl^-: Chloride channel	Cystic fibrosis transmembrane conductance regulator
Porin	Aquaporin (1, 2, 3, 4) • Voltage-dependent anion channel (1)
Cations: TRP	TRPA (1) • TRPC (1, 2, 3, 4, 4AP, 5, 6, 7) • TRPM (1, 2, 3, 4, 5, 6, 7, 8) • TRPML (Mucolipin-1) • TRPP (1, 2)• TRPV (1, 2, 3, 4, 5, 6)
Other/general	Voltage-gated ion channel • Ligand-gated ion channel • Cyclic nucleotide-gated ion channel (α1, α3, β3, H1, H2, H4) • Stretch-activated ion channel

Categories: Ion channels | Electrophysiology | Membrane biology | Integral membrane proteins

This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Calcium_channel". A list of authors is available in Wikipedia.