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Article: Existence of a transient outward K+ current in guinea pig cardiac myocytes

TitleExistence of a transient outward K+ current in guinea pig cardiac myocytes
Authors
Issue Date2000
PublisherAmerican Physiological Society. The Journal's web site is located at http://intl-ajpheart.physiology.org/
Citation
American Journal Of Physiology - Heart And Circulatory Physiology, 2000, v. 279 n. 1 48-1, p. H130-H138 How to Cite?
AbstractA novel transient outward K+ current that exhibits inward-going rectification (I(to.ir)) was identified in guinea pig atrial and ventricular myocytes. I(to.ir) was insensitive to 4-aminopyridine (4-AP) but was blocked by 200 μmol/1 Ba2+ or removal of external K+. The zero current potential shifted 51-53 mv/decade change in external K+. I(to.ir) density was twofold greater in ventricular than in atrial myocytes, and biexponential inactivation occurs in both types of myocytes. At -20 mv, the fast inactivation time constants were 7.7 ± 1.8 and 6.1 ± 1.2 ms and the slow inactivation time constants were 85.1 ± 14.8 and 77.3 ± 10.4 ms in ventricular and atrial cells, respectively. The midpoints for steady-state inactivation were -36.4 ± 0.3 and -51.6 ± 0.4 mV, and recovery from inactivation was rapid near the resting potential (time constants = 7.9 ± 1.9 and 8.8 ± 2.1 ms, respectively). I(to.ir) was detected in Na+-containing and Na+-free solutions and was not blocked by 20 nmol/1 saxitexin. Action potential clamp revealed that I(to.ir) contributed an outward crescent that activated rapidly on depolarization and inactivated by early phase 2 in both tissues. Although it is well knower, that 4-AP-sensitive transient outward current is absent in guinea pig, this Ba2+-sensitive and 4-AP-insensitive K+ current has been overlooked.
Persistent Identifierhttp://hdl.handle.net/10722/162392
ISSN
2015 Impact Factor: 3.324
2015 SCImago Journal Rankings: 1.823
ISI Accession Number ID
References

 

DC FieldValueLanguage
dc.contributor.authorLi, GRen_US
dc.contributor.authorYang, Ben_US
dc.contributor.authorSun, Hen_US
dc.contributor.authorBaumgarten, CMen_US
dc.date.accessioned2012-09-05T05:19:33Z-
dc.date.available2012-09-05T05:19:33Z-
dc.date.issued2000en_US
dc.identifier.citationAmerican Journal Of Physiology - Heart And Circulatory Physiology, 2000, v. 279 n. 1 48-1, p. H130-H138en_US
dc.identifier.issn0363-6135en_US
dc.identifier.urihttp://hdl.handle.net/10722/162392-
dc.description.abstractA novel transient outward K+ current that exhibits inward-going rectification (I(to.ir)) was identified in guinea pig atrial and ventricular myocytes. I(to.ir) was insensitive to 4-aminopyridine (4-AP) but was blocked by 200 μmol/1 Ba2+ or removal of external K+. The zero current potential shifted 51-53 mv/decade change in external K+. I(to.ir) density was twofold greater in ventricular than in atrial myocytes, and biexponential inactivation occurs in both types of myocytes. At -20 mv, the fast inactivation time constants were 7.7 ± 1.8 and 6.1 ± 1.2 ms and the slow inactivation time constants were 85.1 ± 14.8 and 77.3 ± 10.4 ms in ventricular and atrial cells, respectively. The midpoints for steady-state inactivation were -36.4 ± 0.3 and -51.6 ± 0.4 mV, and recovery from inactivation was rapid near the resting potential (time constants = 7.9 ± 1.9 and 8.8 ± 2.1 ms, respectively). I(to.ir) was detected in Na+-containing and Na+-free solutions and was not blocked by 20 nmol/1 saxitexin. Action potential clamp revealed that I(to.ir) contributed an outward crescent that activated rapidly on depolarization and inactivated by early phase 2 in both tissues. Although it is well knower, that 4-AP-sensitive transient outward current is absent in guinea pig, this Ba2+-sensitive and 4-AP-insensitive K+ current has been overlooked.en_US
dc.languageengen_US
dc.publisherAmerican Physiological Society. The Journal's web site is located at http://intl-ajpheart.physiology.org/en_US
dc.relation.ispartofAmerican Journal of Physiology - Heart and Circulatory Physiologyen_US
dc.subject.mesh4-Aminopyridine - Pharmacologyen_US
dc.subject.meshAction Potentials - Drug Effects - Physiologyen_US
dc.subject.meshAnimalsen_US
dc.subject.meshBarium - Pharmacologyen_US
dc.subject.meshCells, Cultureden_US
dc.subject.meshGuinea Pigsen_US
dc.subject.meshHeart - Physiologyen_US
dc.subject.meshHeart Atriaen_US
dc.subject.meshHeart Ventriclesen_US
dc.subject.meshMembrane Potentials - Drug Effects - Physiologyen_US
dc.subject.meshMyocardium - Cytologyen_US
dc.subject.meshPatch-Clamp Techniquesen_US
dc.subject.meshPotassium - Pharmacologyen_US
dc.subject.meshPotassium Channels - Drug Effects - Physiologyen_US
dc.titleExistence of a transient outward K+ current in guinea pig cardiac myocytesen_US
dc.typeArticleen_US
dc.identifier.emailLi, GR:grli@hkucc.hku.hken_US
dc.identifier.authorityLi, GR=rp00476en_US
dc.description.naturelink_to_subscribed_fulltexten_US
dc.identifier.pmid10899050-
dc.identifier.scopuseid_2-s2.0-0033869830en_US
dc.relation.referenceshttp://www.scopus.com/mlt/select.url?eid=2-s2.0-0033869830&selection=ref&src=s&origin=recordpageen_US
dc.identifier.volume279en_US
dc.identifier.issue1 48-1en_US
dc.identifier.spageH130en_US
dc.identifier.epageH138en_US
dc.identifier.isiWOS:000088302100016-
dc.publisher.placeUnited Statesen_US
dc.identifier.scopusauthoridLi, GR=7408462932en_US
dc.identifier.scopusauthoridYang, B=7404472748en_US
dc.identifier.scopusauthoridSun, H=35723049200en_US
dc.identifier.scopusauthoridBaumgarten, CM=7006283434en_US

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