Draslíkový kanál

Draslíkový kanál je iontový kanál umožňující kontrolovaný transport iontů draslíku přes membránu. Obvykle se jedná o kanály, které propouštějí draslík ven z buňky a v nejtypičtějším případě jsou umístěny na cytoplazmatických membránách nervových buněk. Zde se podílí na vzniku nervových vzruchů, podílejí se na obnově klidového potenciálu a regulaci vzniku akčních potenciálů.^[1]

Obecně však mohou draslíkové kanály spadat do několika kategorií: některé se otevírají vlivem změněné polarity membrány (napěťově řízené kanály), jiné reagují na zvýšenou koncentraci vápníku nebo zvýšení poměru ATP/ADP v buňce, další reagují až po navázání ligandu na receptor. Draslíkové kanály mají obvykle šest nebo dvě transmembránové domény.^[1]

Typy draslíkových kanálů^[2]
Třída	Podřídy	Funkce	Blokátory	Aktivátory
Vápnikem aktivovaný draslíkový kanál 6T & 1P	BK kanál SK kanál IK kanál	inhibice důsledkem zvýšení intracelulární koncentrace vápníku, aktivovány částí metabotropních (Gq) receptorů	charybdotoxin, iberiotoxin apamin	1-EBIO NS309 CyPPA
Inwardly rectifying 2T & 1P	ROMK (K_ir1.1)	recyklace a vylučování draslíku v nefron	Neselektivně: Ba²⁺, Cs⁺	none
	GPCR regulated (K_ir3.x)	zprostředkuje inhibici mnohaGPCRs	GPCR antagonisté ifenprodil^[3]	GPCR agonisté
	ATP-sensitive (K_ir6.x)	zavřený pokud je dost ATP k sekreci inzulinu	glibenclamid tolbutamid	diazoxid pinacidil minoxidil nicorandil
Tandememová doména 4T & 2P	TWIK (TWIK-1, TWIK-2, KCNK7)^[4]^[5] TREK (TREK-1, TREK-2, TRAAK^[6])^[4]^[5] TASK (TASK-1, TASK-3, TASK-5)^[4]^[5] TALK (TASK-2,^[7] TALK-1, TALK-2)^[4]^[5] THIK (THIK-1, THIK-2)^[4]^[5] TRESK^[4]^[5]^[8]^[9]	podporuje klidový membránový potenciál, otevřené i při klidovém mebrálovém potenciálu	bupivacaine^[10]^[11]^[12]^[13] quinidine^[11]^[14]^[15]^[16]^[17]	halothane^[11]^[18]^[19]
Napěťově řízený draslíkový kanál 6T & 1P	hERG (K_v11.1) KvLQT1 (K_v7.1)	akční potenciál repolarizace omezuje frekvence akčních potenciálů (poruchy způsobují arytmie),	tetraethylamonium 4-aminopyridin dendrotoxins (měkteré typy)	retigabine (K_v7)^[20]

Reference

↑ ^a ^b Oxford dictionary of biochemistry and molecular biology; revised edition. Příprava vydání R. Cammack et al. New York: Oxford university press, 2006. ISBN 0-19-852917-1.
↑ Rang, HP. Pharmacology. Edinburgh: Churchill Livingstone, 2003. ISBN 0-443-07145-4. S. 60.
↑ Kobayashi T, Washiyama K, Ikeda K. Inhibition of G protein-activated inwardly rectifying K+ channels by ifenprodil. Neuropsychopharmacology. Mar 2006, s. 516–24. DOI 10.1038/sj.npp.1300844. PMID 16123769.
↑ ^a ^b ^c ^d ^e ^f Enyedi P, Czirják G. Molecular background of leak K+ currents: two-pore domain potassium channels. Physiological Reviews. Apr 2010, s. 559–605. DOI 10.1152/physrev.00029.2009. PMID 20393194.
↑ ^a ^b ^c ^d ^e ^f Lotshaw DP. Biophysical, pharmacological, and functional characteristics of cloned and native mammalian two-pore domain K+ channels. Cell Biochemistry and Biophysics. 2007, s. 209–56. DOI 10.1007/s12013-007-0007-8. PMID 17652773.
↑ Fink M, Lesage F, Duprat F, Heurteaux C, Reyes R, Fosset M, Lazdunski M. A neuronal two P domain K+ channel stimulated by arachidonic acid and polyunsaturated fatty acids. The EMBO Journal. Jun 1998, s. 3297–308. DOI 10.1093/emboj/17.12.3297. PMID 9628867.
↑ Goldstein SA, Bockenhauer D, O'Kelly I, Zilberberg N. Potassium leak channels and the KCNK family of two-P-domain subunits. Nature Reviews. Neuroscience. Mar 2001, s. 175–84. DOI 10.1038/35058574. PMID 11256078.
↑ Sano Y, Inamura K, Miyake A, Mochizuki S, Kitada C, Yokoi H, Nozawa K, Okada H, Matsushime H, Furuichi K. A novel two-pore domain K+ channel, TRESK, is localized in the spinal cord. The Journal of Biological Chemistry. Jul 2003, s. 27406–12. DOI 10.1074/jbc.M206810200. PMID 12754259.
↑ Czirják G, Tóth ZE, Enyedi P. The two-pore domain K+ channel, TRESK, is activated by the cytoplasmic calcium signal through calcineurin. The Journal of Biological Chemistry. Apr 2004, s. 18550–8. DOI 10.1074/jbc.M312229200. PMID 14981085.
↑ Kindler CH, Yost CS, Gray AT. Local anesthetic inhibition of baseline potassium channels with two pore domains in tandem. Anesthesiology. Apr 1999, s. 1092–102. DOI 10.1097/00000542-199904000-00024. PMID 10201682.
↑ ^a ^b ^c Meadows HJ, Randall AD. Functional characterisation of human TASK-3, an acid-sensitive two-pore domain potassium channel. Neuropharmacology. Mar 2001, s. 551–9. DOI 10.1016/S0028-3908(00)00189-1. PMID 11249964.
↑ Kindler CH, Paul M, Zou H, Liu C, Winegar BD, Gray AT, Yost CS. Amide local anesthetics potently inhibit the human tandem pore domain background K+ channel TASK-2 (KCNK5). The Journal of Pharmacology and Experimental Therapeutics. Jul 2003, s. 84–92. DOI 10.1124/jpet.103.049809. PMID 12660311.
↑ Punke MA, Licher T, Pongs O, Friederich P. Inhibition of human TREK-1 channels by bupivacaine. Anesthesia and Analgesia. Jun 2003, s. 1665–73. DOI 10.1213/01.ANE.0000062524.90936.1F. PMID 12760993.
↑ Lesage F, Guillemare E, Fink M, Duprat F, Lazdunski M, Romey G, Barhanin J. TWIK-1, a ubiquitous human weakly inward rectifying K+ channel with a novel structure. The EMBO Journal. Mar 1996, s. 1004–11. PMID 8605869.
↑ Duprat F, Lesage F, Fink M, Reyes R, Heurteaux C, Lazdunski M. TASK, a human background K+ channel to sense external pH variations near physiological pH. The EMBO Journal. Sep 1997, s. 5464–71. DOI 10.1093/emboj/16.17.5464. PMID 9312005.
↑ Reyes R, Duprat F, Lesage F, Fink M, Salinas M, Farman N, Lazdunski M. Cloning and expression of a novel pH-sensitive two pore domain K+ channel from human kidney. The Journal of Biological Chemistry. Nov 1998, s. 30863–9. DOI 10.1074/jbc.273.47.30863. PMID 9812978.
↑ Meadows HJ, Benham CD, Cairns W, Gloger I, Jennings C, Medhurst AD, Murdock P, Chapman CG. Cloning, localisation and functional expression of the human orthologue of the TREK-1 potassium channel. Pflügers Archiv. Apr 2000, s. 714–22. DOI 10.1007/s004240050997. PMID 10784345.
↑ Patel AJ, Honoré E, Lesage F, Fink M, Romey G, Lazdunski M. Inhalational anesthetics activate two-pore-domain background K+ channels. Nature Neuroscience. May 1999, s. 422–6. DOI 10.1038/8084. PMID 10321245.
↑ Gray AT, Zhao BB, Kindler CH, Winegar BD, Mazurek MJ, Xu J, Chavez RA, Forsayeth JR, Yost CS. Volatile anesthetics activate the human tandem pore domain baseline K+ channel KCNK5. Anesthesiology. Jun 2000, s. 1722–30. DOI 10.1097/00000542-200006000-00032. PMID 10839924.
↑ Rogawski MA, Bazil CW. New molecular targets for antiepileptic drugs: alpha(2)delta, SV2A, and K(v)7/KCNQ/M potassium channels. Current Neurology and Neuroscience Reports. Jul 2008, s. 345–52. DOI 10.1007/s11910-008-0053-7. PMID 18590620.

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[cammack-1] Oxford dictionary of biochemistry and molecular biology; revised edition. Příprava vydání R. Cammack et al. New York: Oxford university press, 2006. ISBN 0-19-852917-1.

[Rang60-2] Rang, HP. Pharmacology. Edinburgh: Churchill Livingstone, 2003. ISBN 0-443-07145-4. S. 60.

[pmid16123769-3] Kobayashi T, Washiyama K, Ikeda K. Inhibition of G protein-activated inwardly rectifying K+ channels by ifenprodil. Neuropsychopharmacology. Mar 2006, s. 516–24. DOI 10.1038/sj.npp.1300844. PMID 16123769.

[pmid20393194-4] ↑ ^a ^b ^c ^d ^e ^f Enyedi P, Czirják G. Molecular background of leak K+ currents: two-pore domain potassium channels. Physiological Reviews. Apr 2010, s. 559–605. DOI 10.1152/physrev.00029.2009. PMID 20393194.

[pmid17652773-5] ↑ ^a ^b ^c ^d ^e ^f Lotshaw DP. Biophysical, pharmacological, and functional characteristics of cloned and native mammalian two-pore domain K+ channels. Cell Biochemistry and Biophysics. 2007, s. 209–56. DOI 10.1007/s12013-007-0007-8. PMID 17652773.

[pmid9628867-6] Fink M, Lesage F, Duprat F, Heurteaux C, Reyes R, Fosset M, Lazdunski M. A neuronal two P domain K+ channel stimulated by arachidonic acid and polyunsaturated fatty acids. The EMBO Journal. Jun 1998, s. 3297–308. DOI 10.1093/emboj/17.12.3297. PMID 9628867.

[pmid11256078-7] Goldstein SA, Bockenhauer D, O'Kelly I, Zilberberg N. Potassium leak channels and the KCNK family of two-P-domain subunits. Nature Reviews. Neuroscience. Mar 2001, s. 175–84. DOI 10.1038/35058574. PMID 11256078.

[pmid12754259-8] Sano Y, Inamura K, Miyake A, Mochizuki S, Kitada C, Yokoi H, Nozawa K, Okada H, Matsushime H, Furuichi K. A novel two-pore domain K+ channel, TRESK, is localized in the spinal cord. The Journal of Biological Chemistry. Jul 2003, s. 27406–12. DOI 10.1074/jbc.M206810200. PMID 12754259.

[pmid14981085-9] Czirják G, Tóth ZE, Enyedi P. The two-pore domain K+ channel, TRESK, is activated by the cytoplasmic calcium signal through calcineurin. The Journal of Biological Chemistry. Apr 2004, s. 18550–8. DOI 10.1074/jbc.M312229200. PMID 14981085.

[pmid10201682-10] Kindler CH, Yost CS, Gray AT. Local anesthetic inhibition of baseline potassium channels with two pore domains in tandem. Anesthesiology. Apr 1999, s. 1092–102. DOI 10.1097/00000542-199904000-00024. PMID 10201682.

[pmid11249964-11] Meadows HJ, Randall AD. Functional characterisation of human TASK-3, an acid-sensitive two-pore domain potassium channel. Neuropharmacology. Mar 2001, s. 551–9. DOI 10.1016/S0028-3908(00)00189-1. PMID 11249964.

[pmid12660311-12] Kindler CH, Paul M, Zou H, Liu C, Winegar BD, Gray AT, Yost CS. Amide local anesthetics potently inhibit the human tandem pore domain background K+ channel TASK-2 (KCNK5). The Journal of Pharmacology and Experimental Therapeutics. Jul 2003, s. 84–92. DOI 10.1124/jpet.103.049809. PMID 12660311.

[pmid12760993-13] Punke MA, Licher T, Pongs O, Friederich P. Inhibition of human TREK-1 channels by bupivacaine. Anesthesia and Analgesia. Jun 2003, s. 1665–73. DOI 10.1213/01.ANE.0000062524.90936.1F. PMID 12760993.

[pmid8605869-14] Lesage F, Guillemare E, Fink M, Duprat F, Lazdunski M, Romey G, Barhanin J. TWIK-1, a ubiquitous human weakly inward rectifying K+ channel with a novel structure. The EMBO Journal. Mar 1996, s. 1004–11. PMID 8605869.

[pmid9312005-15] Duprat F, Lesage F, Fink M, Reyes R, Heurteaux C, Lazdunski M. TASK, a human background K+ channel to sense external pH variations near physiological pH. The EMBO Journal. Sep 1997, s. 5464–71. DOI 10.1093/emboj/16.17.5464. PMID 9312005.

[pmid9812978-16] Reyes R, Duprat F, Lesage F, Fink M, Salinas M, Farman N, Lazdunski M. Cloning and expression of a novel pH-sensitive two pore domain K+ channel from human kidney. The Journal of Biological Chemistry. Nov 1998, s. 30863–9. DOI 10.1074/jbc.273.47.30863. PMID 9812978.

[pmid10784345-17] Meadows HJ, Benham CD, Cairns W, Gloger I, Jennings C, Medhurst AD, Murdock P, Chapman CG. Cloning, localisation and functional expression of the human orthologue of the TREK-1 potassium channel. Pflügers Archiv. Apr 2000, s. 714–22. DOI 10.1007/s004240050997. PMID 10784345.

[pmid10321245-18] Patel AJ, Honoré E, Lesage F, Fink M, Romey G, Lazdunski M. Inhalational anesthetics activate two-pore-domain background K+ channels. Nature Neuroscience. May 1999, s. 422–6. DOI 10.1038/8084. PMID 10321245.

[pmid10839924-19] Gray AT, Zhao BB, Kindler CH, Winegar BD, Mazurek MJ, Xu J, Chavez RA, Forsayeth JR, Yost CS. Volatile anesthetics activate the human tandem pore domain baseline K+ channel KCNK5. Anesthesiology. Jun 2000, s. 1722–30. DOI 10.1097/00000542-200006000-00032. PMID 10839924.

[Rogawski-20] Rogawski MA, Bazil CW. New molecular targets for antiepileptic drugs: alpha(2)delta, SV2A, and K(v)7/KCNQ/M potassium channels. Current Neurology and Neuroscience Reports. Jul 2008, s. 345–52. DOI 10.1007/s11910-008-0053-7. PMID 18590620.

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