Calcium channel
1513441
200884246
2008-03-25T20:38:40Z
Loodog
783435
/* Ligand-gated */
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|voltage-dependent calcium channel}}
{| class="wikitable" | style="text-align:center"
| '''Type''' || '''Gated by''' || '''Protein''' || '''Gene''' || '''Location''' || '''Function'''
|-
| [[L-type calcium channel|L-type]] || high voltage || [[Cav1.1|Ca<sub>v</sub>1.1]]<br /> [[Cav1.2|Ca<sub>v</sub>1.2]]<br /> [[Cav1.3|Ca<sub>v</sub>1.3]]<br /> [[Cav1.4|Ca<sub>v</sub>1.4]]<br /> || {{Gene|CACNA1S}}<br /> {{Gene|CACNA1C}}<br /> {{Gene|CACNA1D}}<br /> {{Gene|CACNA1F}} || Skeletal muscle, bone (osteoblasts), ventricular myocytes**, dendrites and dendritic spines of cortical neurones || [[smooth muscle cell|SMC]] and [[cardiac muscle]] contraction <ref name=Rang53/>. Responsible for prolonged action potential in [[cardiac muscle]].
|-
| [[P-type calcium channel|P-type]]/[[Q-type calcium channel|Q-type]] || high voltage || [[Cav2.1|Ca<sub>v</sub>2.1]] || {{Gene|CACNA1A}} || [[Purkinje neurons]] in the cerebellum / [[Cerebellum| Cerebellar]] [[granule cell]]s || [[neurotransmitter]] release <ref name=Rang53/>
|-
| [[N-type calcium channel|N-type]] || high voltage || Ca<sub>v</sub>2.2 || {{Gene|CACNA1B}} || Throughout the [[brain]] || [[neurotransmitter]] release <ref name=Rang53/>
|-
| [[R-type calcium channel|R-type]] || intermediate voltage || Ca<sub>v</sub>2.3 || {{Gene|CACNA1E}} || [[Cerebellum| Cerebellar]] [[granule cell]]s, other neurons || ?<ref name=Rang53/>
|-
| [[T-type calcium channel|T-type]] || low voltage || Ca<sub>v</sub>3.1<br /> Ca<sub>v</sub>3.2<br /> Ca<sub>v</sub>3.3<br /> || {{Gene|CACNA1G}}<br /> {{Gene|CACNA1H}} <br /> {{Gene|CACNA1I}} || neurons, cells that have pacemaker activity, bone (osteocytes) || Regular [[sinus rhythm]]<ref name=Rang53/>
|}
===[[Ligand-gated ion channel|Ligand-gated]]===
*the ''receptor-operated calcium channels'' (in [[vasoconstriction]])
**[[P2X receptor]] <ref name=boron> {{cite book |author=Walter F., PhD. Boron |title=Medical Physiology: A Cellular And Molecular Approaoch |publisher=Elsevier/Saunders |location= |year= |pages= |isbn=1-4160-2328-3 |oclc= |doi=}} Page 479 </ref>
{| class="wikitable" | style="text-align:center"
| '''Type''' || '''Gated by''' || '''Gene''' || '''Location''' || '''Function'''
|-
| [[inositol triphosphate receptor|IP<sub>3</sub> receptor]] || [[inositol triphosphate|IP<sub>3</sub>]] || || [[endoplasmic reticulum|ER]]/[[sarcoplasmic reticulum|SR]] || Releases calcium from ER/SR in response to IP<sub>3</sub> by e.g. [[GPCR]]s <ref name=Rang53> {{cite book |author=Rang, H. P. |title=Pharmacology |publisher=Churchill Livingstone |location=Edinburgh |year=2003 |pages= |isbn=0-443-07145-4 |oclc= |doi=}} Page 53</ref>
|-
| [[Ryanodine receptor]] || [[dihydropyridine receptor]]s in [[T-tubule]]s || || [[endoplasmic reticulum|ER]]/[[sarcoplasmic reticulum|SR]] || [[Calcium-induced calcium release]] in [[myocyte]]s <ref name=Rang53/>
|-
| [[Two-pore channel]] || || || ||
|-
| [[Cation channels of sperm]] || || || ||
|-
| ''store-operated channels'' || indirectly by [[endoplasmic reticulum|ER]]/[[sarcoplasmic reticulum|SR]] depletion of calcium<ref name=Rang53/> || || [[plasma membrane]] ||
|-
|}
==Pharmacology==
[[Calcium channel blocker]]s are used to treat [[hypertension]].
==References==
<references/>
==External links==
* {{MeshName|Calcium+Channels}}
{{Ion channels}}
[[Category:Ion channels]]
[[Category:Electrophysiology]]
[[Category:Membrane biology]]
[[Category:Integral membrane proteins]]
[[de:Calciumkanal]]
[[fr:Canal calcique]]
[[pl:KanaĆ wapniowy]]