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,[1] although there are also ligand-gated calcium channels.[2]
Comparison tables
The following tables explain gating, gene, location and function of different types of calcium channels, both voltage and ligand-gated.
Voltage-gated
| 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 neurons | SMC and cardiac muscle contraction [3]. 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 [3] |
| N-type | high voltage | Cav2.2 | CACNA1B | Throughout the brain | neurotransmitter release [3] |
| R-type | intermediate voltage | Cav2.3 | CACNA1E | Cerebellar granule cells, other neurons | ?[3] |
| T-type | low voltage | Cav3.1 Cav3.2 Cav3.3 |
CACNA1G CACNA1H CACNA1I |
neurons, cells that have pacemaker activity, bone (osteocytes) | Regular sinus rhythm[3] |
- the receptor-operated calcium channels (in vasoconstriction)
| Type | Gated by | Gene | Location | Function |
| IP3 receptor | IP3 | ITPR1, ITPR2, ITPR3 | ER/SR | Releases calcium from ER/SR in response to IP3 by e.g. GPCRs [3] |
| Ryanodine receptor | dihydropyridine receptors in T-tubules and increased intracellular calcium (Calcium Induced Calcium Release - CICR) | RYR1, RYR2, RYR3 | ER/SR | Calcium-induced calcium release in myocytes [3] |
| Two-pore channel | ||||
| Cation channels of sperm | ||||
| store-operated channels | indirectly by ER/SR depletion of calcium[3] | ORAI1, ORAI2, ORAI3 | plasma membrane |
Pharmacology
Calcium channel blockers are used to treat hypertension.
References
- ^ "calcium channel" at Dorland's Medical Dictionary
- ^ Striggow F, Ehrlich BE (1996). "Ligand-gated calcium channels inside and out". Curr. Opin. Cell Biol. 8 (4): 490–5. doi:10.1016/S0955-0674(96)80025-1. PMID 8791458.
{{cite journal}}: Unknown parameter|month=ignored (help) - ^ 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 (2005). Medical Physiology: A Cellular And Molecular Approach. Elsevier/Saunders. ISBN 1-4160-2328-3. Page 479
External links
- "Voltage-Gated Ion Channels". IUPHAR Database of Receptors and Ion Channels. International Union of Basic and Clinical Pharmacology.
{{cite web}}: Cite has empty unknown parameter:|coauthors=(help) - "TRIP Database". a manually curated database of protein-protein interactions for mammalian TRP channels.
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- Calcium+Channels at the U.S. National Library of Medicine Medical Subject Headings (MeSH)