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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
KeywordsAction potential configuration
Excitability
Repolarization
Transient outward potassium current
Whole cell patch clamp
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
2023 Impact Factor: 4.1
2023 SCImago Journal Rankings: 1.452
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.subjectAction potential configuration-
dc.subjectExcitability-
dc.subjectRepolarization-
dc.subjectTransient outward potassium current-
dc.subjectWhole cell patch clamp-
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
dc.identifier.issnl0363-6135-

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