Calcium channels are a family of ion channels selectively permeable to calcium ions Ca 2+ . Often this term is synonymous with voltage-gated calcium channels, although ligand-dependent calcium channels also exist [1] .
For example, the inositol triphosphate receptor (IP 3 ) is a ligand-dependent calcium channel, and its endogenous ligand , an agonist, is IP 3 . The IP 3 receptor is located in the membrane of the endoplasmic reticulum and sarcoplasmic muscle reticulum . After binding to IP 3 it releases calcium ions from the calcium depots of the reticulum. The appearance of IP 3 in the cytoplasm of a cell can be caused by the activation of receptors associated with G-proteins .
Calcium channel blockers are used to treat high blood pressure , pain , epileptic seizures [2] . Their clinical trials are underway in relation to Parkinson's disease [2] . Since calcium channels play an important role in the formation of drug addiction , their inhibitors are promising for the treatment of this disease [2] . Many calcium channel blockers are promising for the treatment of psychiatric diseases and have an anxiolytic effect [2] .
Content
Channel Types
The following tables contain information on the different types of calcium channels, potential and ligand-controlled. Information on biophysical properties, location, coding genes and functions is provided.
Potentially
| Type of | Activation | Protein | Gene | Location | Function |
| L-type | high threshold calcium channels (activated at high values of membrane potential) | Ca v 1.1 Ca v 1.2 Ca v 1.3 Ca v 1.4 | CACNA1S CACNA1C CACNA1D CACNA1F | Skeletal muscles, bones (osteoblasts), ventricular myocytes , dendrites and spines of dendrites of neurons of the cerebral cortex | Contraction of the heart muscle and smooth muscle [3] . Responsible for the extended action potential in the heart muscle. |
| P-type / Q-type | high threshold calcium channels | Ca v 2.1 | CACNA1A | Purkinje neurons in the cerebellum / cerebellar granular cells | neurotransmitter release [3] |
| N-type | high threshold calcium channels | Ca v 2.2 | CACNA1B | All over the brain | neurotransmitter release [3] |
| R-type | intermediate activation threshold | Ca v 2.3 | CACNA1E | cerebellar granular cells , other neurons | ? [3] |
| T-type | low threshold calcium channels | Ca v 3.1 Ca v 3.2 Ca v 3.3 | CACNA1G CACNA1H CACNA1I | neurons, cells with pacemaker activity, bones (osteocytes) | regular sinus rhythm [3] |
Managed Ligands
- receptor-driven calcium channels (in vasoconstriction)
- P2X Receptor [4]
| Type of | Activation | Gene | Location | Function |
| Inositol Triphosphate Receptor (IP 3 ) | IP 3 | endoplasmic reticulum and sarcoplasmic reticulum | After binding to IP 3 releases calcium ions. The appearance of IP 3 in the cytoplasm of a cell can be caused by activation of receptors associated with G-proteins [3] . | |
| Ryanodine receptor | T-tube dihydropyridine receptors and increased intracellular calcium concentration (Calcium Induced Calcium Release - CICR) | endoplasmic reticulum and sarcoplasmic reticulum | Calcium-induced release of calcium in myocytes [3] | |
| Two-pore channel | ||||
| Cationic channels of sperm | ||||
| calcium depot controlled channels | indirectly due to depletion of calcium in the endoplasmic reticulum and sarcoplasmic reticulum [3] | plasma membrane |
Notes
- ↑ Striggow F., Ehrlich BE Ligand-gated calcium channels inside and out (English) // Curr. Opin. Cell Biol. . - Elsevier , 1996 .-- August ( vol. 8 , no. 4 ). - P. 490-495 . - DOI : 10.1016 / S0955-0674 (96) 80025-1 . - PMID 8791458 .
- ↑ 1 2 3 4 Zamponi GW Targeting voltage-gated calcium channels in neurological and psychiatric diseases (Eng.) // Nat. Rev. Drug Discov .. - 2016. - Vol. 15 . - P. 19—34 . - DOI : 10.1038 / nrd.2015.5 .
- ↑ 1 2 3 4 5 6 7 8 Rang, HP Pharmacology. - Edinburgh: Churchill Livingstone, 2003 .-- P. 53. - ISBN 0-443-07145-4 .
- ↑ Walter F., PhD. Boron Medical Physiology: A Cellular And Molecular Approach. - Elsevier / Saunders, 2005 .-- P. 479. - ISBN 1-4160-2328-3 .