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Article: Demonstration of calcium-activated transient outward chloride current and delayed rectifier potassium currents in Swine atrial myocytes

TitleDemonstration of calcium-activated transient outward chloride current and delayed rectifier potassium currents in Swine atrial myocytes
Authors
KeywordsCellular electrophysiology
Cl- current
Delayed rectifier K+ currents
Heart
Pig atrial myocytes
Issue Date2004
PublisherAcademic Press. The Journal's web site is located at http://www.elsevier.com/locate/yjmcc
Citation
Journal Of Molecular And Cellular Cardiology, 2004, v. 36 n. 4, p. 495-504 How to Cite?
AbstractCellular electrophysiology is not fully understood in the atrium of pig heart. The objective of the present study was to determine whether transient outward current (Ito), ultra-rapid delayed rectifier potassium current (IKur), and rapid and slow delayed rectifier K+ currents (IKr and IKs) were present in pig atrium. The whole-cell patch technique was applied to record membrane currents and action potentials in myocytes isolated from pig atrium. It was found that an I to was activated upon depolarization voltage steps to between -10 and +60 mV from -50 mV in pig atrial cells, and the Ito was sensitive to the inhibition by the blockade of L-type calcium (Ca2+) current, showed a "bell-shaped" I-V relationship, typical of I to2 (i.e. ICl.Ca). The Ito2 was inhibited by the chloride (Cl-) channel blocker anthracene-9-carboxylic acid (9-AC, 200 μmol/l) or 4,4′-diisothiocyanostilben-2,2′disulfonic acid (200 μmol/l), and by Cl- substitution in the superfusate. IKur was found in pig atrial myocytes, and the current showed properties of weak inward rectification and use- and frequency-dependent reduction. IKur was resistant to tetraethylammonium, but sensitive to inhibition by 4-aminopyridine (4-AP) (IC50 = 71.7 ± 3.5 μmol/l). In addition, E-4031-sensitive IKr and chromanol 293B-sensitive IKs were observed in pig atrial myocytes. Blockade of Ito2, IKur, IKr or IKs with corresponding blockers significantly prolonged atrial action potentials. These results indicate that Ca2+-activated Ito2, 4-AP-sensitive IKur, E-4031-sensitive IKr, and 293B-sensitive I Ks are present in pig atrial myocytes, and these currents play important roles in action potential repolarization of pig atria. © 2004 Elsevier Ltd. All rights reserved.
Persistent Identifierhttp://hdl.handle.net/10722/76905
ISSN
2015 Impact Factor: 4.874
2015 SCImago Journal Rankings: 2.522
ISI Accession Number ID
References

 

DC FieldValueLanguage
dc.contributor.authorLi, GRen_HK
dc.contributor.authorSun, Hen_HK
dc.contributor.authorTo, Jen_HK
dc.contributor.authorTse, HFen_HK
dc.contributor.authorLau, CPen_HK
dc.date.accessioned2010-09-06T07:26:11Z-
dc.date.available2010-09-06T07:26:11Z-
dc.date.issued2004en_HK
dc.identifier.citationJournal Of Molecular And Cellular Cardiology, 2004, v. 36 n. 4, p. 495-504en_HK
dc.identifier.issn0022-2828en_HK
dc.identifier.urihttp://hdl.handle.net/10722/76905-
dc.description.abstractCellular electrophysiology is not fully understood in the atrium of pig heart. The objective of the present study was to determine whether transient outward current (Ito), ultra-rapid delayed rectifier potassium current (IKur), and rapid and slow delayed rectifier K+ currents (IKr and IKs) were present in pig atrium. The whole-cell patch technique was applied to record membrane currents and action potentials in myocytes isolated from pig atrium. It was found that an I to was activated upon depolarization voltage steps to between -10 and +60 mV from -50 mV in pig atrial cells, and the Ito was sensitive to the inhibition by the blockade of L-type calcium (Ca2+) current, showed a "bell-shaped" I-V relationship, typical of I to2 (i.e. ICl.Ca). The Ito2 was inhibited by the chloride (Cl-) channel blocker anthracene-9-carboxylic acid (9-AC, 200 μmol/l) or 4,4′-diisothiocyanostilben-2,2′disulfonic acid (200 μmol/l), and by Cl- substitution in the superfusate. IKur was found in pig atrial myocytes, and the current showed properties of weak inward rectification and use- and frequency-dependent reduction. IKur was resistant to tetraethylammonium, but sensitive to inhibition by 4-aminopyridine (4-AP) (IC50 = 71.7 ± 3.5 μmol/l). In addition, E-4031-sensitive IKr and chromanol 293B-sensitive IKs were observed in pig atrial myocytes. Blockade of Ito2, IKur, IKr or IKs with corresponding blockers significantly prolonged atrial action potentials. These results indicate that Ca2+-activated Ito2, 4-AP-sensitive IKur, E-4031-sensitive IKr, and 293B-sensitive I Ks are present in pig atrial myocytes, and these currents play important roles in action potential repolarization of pig atria. © 2004 Elsevier Ltd. All rights reserved.en_HK
dc.languageengen_HK
dc.publisherAcademic Press. The Journal's web site is located at http://www.elsevier.com/locate/yjmccen_HK
dc.relation.ispartofJournal of Molecular and Cellular Cardiologyen_HK
dc.subjectCellular electrophysiologyen_HK
dc.subjectCl- currenten_HK
dc.subjectDelayed rectifier K+ currentsen_HK
dc.subjectHearten_HK
dc.subjectPig atrial myocytesen_HK
dc.subject.mesh4-Aminopyridine - pharmacology-
dc.subject.meshAnimals-
dc.subject.meshCalcium - metabolism-
dc.subject.meshChloride Channels - chemistry-
dc.subject.meshHeart Atria - cytology - pathology-
dc.titleDemonstration of calcium-activated transient outward chloride current and delayed rectifier potassium currents in Swine atrial myocytesen_HK
dc.typeArticleen_HK
dc.identifier.openurlhttp://library.hku.hk:4550/resserv?sid=HKU:IR&issn=0022-2828&volume=36&issue=4&spage=495&epage=504&date=2004&atitle=Demonstration+of+calcium-activated+transient+outward+chloride+current+and+delayed+rectifier+potassium+currents+in+Swine+atrial+myocytesen_HK
dc.identifier.emailLi, GR:grli@hkucc.hku.hken_HK
dc.identifier.emailTse, HF:hftse@hkucc.hku.hken_HK
dc.identifier.authorityLi, GR=rp00476en_HK
dc.identifier.authorityTse, HF=rp00428en_HK
dc.description.naturelink_to_subscribed_fulltext-
dc.identifier.doi10.1016/j.yjmcc.2004.01.005en_HK
dc.identifier.pmid15081309-
dc.identifier.scopuseid_2-s2.0-1842765608en_HK
dc.identifier.hkuros88551en_HK
dc.relation.referenceshttp://www.scopus.com/mlt/select.url?eid=2-s2.0-1842765608&selection=ref&src=s&origin=recordpageen_HK
dc.identifier.volume36en_HK
dc.identifier.issue4en_HK
dc.identifier.spage495en_HK
dc.identifier.epage504en_HK
dc.identifier.isiWOS:000221181400005-
dc.publisher.placeUnited Kingdomen_HK
dc.identifier.scopusauthoridLi, GR=7408462932en_HK
dc.identifier.scopusauthoridSun, H=35723049200en_HK
dc.identifier.scopusauthoridTo, J=36641520100en_HK
dc.identifier.scopusauthoridTse, HF=7006070805en_HK
dc.identifier.scopusauthoridLau, CP=7401968501en_HK

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