DC Field | Value | Language |
---|---|---|
dc.contributor.author | Jo, SH | ko |
dc.contributor.author | Youm, JB | ko |
dc.contributor.author | Kim, Injune | ko |
dc.contributor.author | Lee, CO | ko |
dc.contributor.author | Earm, YE | ko |
dc.contributor.author | Ho, WK | ko |
dc.date.accessioned | 2013-02-28T04:07:55Z | - |
dc.date.available | 2013-02-28T04:07:55Z | - |
dc.date.created | 2012-02-06 | - |
dc.date.created | 2012-02-06 | - |
dc.date.issued | 1999-06 | - |
dc.identifier.citation | PFLUGERS ARCHIV-EUROPEAN JOURNAL OF PHYSIOLOGY, v.438, no.1, pp.23 - 29 | - |
dc.identifier.issn | 0031-6768 | - |
dc.identifier.uri | http://hdl.handle.net/10203/72701 | - |
dc.description.abstract | We have investigated the effect of external H+ concentration ( [H+](o)) on the human-ether-a-go-go-related gene (HERG) current (I-HERG), the molecular equivalent of the cardiac delayed rectifier potassium current (I-Kr), expressed in Xenopus oocytes, using the two-microelectrode voltage-clamp technique. When [H+](o) was increased, the amplitude of the I-HERG elicited by depolarization decreased, and the rate of current decay on repolarization was accelerated. The activation curve shifted to a more positive potential at lower external pH (pH(o)) values (the potential required for half-maximum activation, V-1/2, was: -41.8 mV, -38.0 mV, -33.7 mV, -26.7 mV in pH(o) 8.0, 7.0, 6.6, 6.2, respectively). The maximum conductance (g(max)) was also affected by [H+](o): a reduction of 7.9%, 14.6%, and 22.8% was effected by decreasing pH(o) from 8.0 to 7.0, 6.6, and 6.2, respectively. We then tested whether this pH effect was affected by the external Ca2+ concentration, which is also known to block HERG channels. When the extracellular Ca2+ concentration was increased from 0.5 mM to 5 mM, the shift in V-1/2 caused by increasing [H+](o) was attenuated, suggesting that these two ions compete for the same binding site. On the other hand, the decrease in g(max) caused by increasing [H+], was not significantly affected by changing external Ca2+ levels. The results indicate that HERG channels are inhibited by [H+](o) by two different mechanisms: voltage-dependent blockade (shift of V-1/2) and the decrease in g(max). With respect to the voltage-dependent blockade, the interaction between H+ and Ca2+ is competitive, whereas for the decreasing g(max) their interaction is non-competitive. | - |
dc.language | English | - |
dc.publisher | SPRINGER VERLAG | - |
dc.subject | RAT VENTRICULAR CELLS | - |
dc.subject | RECTIFIER K+ CURRENT | - |
dc.subject | POTASSIUM CHANNEL | - |
dc.subject | CARDIAC-MUSCLE | - |
dc.subject | VOLTAGE-CLAMP | - |
dc.subject | HYDROGEN-IONS | - |
dc.subject | PH | - |
dc.subject | ACIDOSIS | - |
dc.subject | CA2+ | - |
dc.subject | RECTIFICATION | - |
dc.title | Blockade of HERG channels expressed in Xenopus oocytes by external H+ | - |
dc.type | Article | - |
dc.identifier.wosid | 000080561700004 | - |
dc.identifier.scopusid | 2-s2.0-0010165993 | - |
dc.type.rims | ART | - |
dc.citation.volume | 438 | - |
dc.citation.issue | 1 | - |
dc.citation.beginningpage | 23 | - |
dc.citation.endingpage | 29 | - |
dc.citation.publicationname | PFLUGERS ARCHIV-EUROPEAN JOURNAL OF PHYSIOLOGY | - |
dc.identifier.doi | 10.1007/s004240050875 | - |
dc.contributor.localauthor | Kim, Injune | - |
dc.contributor.nonIdAuthor | Jo, SH | - |
dc.contributor.nonIdAuthor | Youm, JB | - |
dc.contributor.nonIdAuthor | Lee, CO | - |
dc.contributor.nonIdAuthor | Earm, YE | - |
dc.contributor.nonIdAuthor | Ho, WK | - |
dc.type.journalArticle | Article | - |
dc.subject.keywordAuthor | Ca2+ | - |
dc.subject.keywordAuthor | channel blockade | - |
dc.subject.keywordAuthor | H+ | - |
dc.subject.keywordAuthor | HERG channel | - |
dc.subject.keywordAuthor | potassium channel | - |
dc.subject.keywordPlus | RAT VENTRICULAR CELLS | - |
dc.subject.keywordPlus | RECTIFIER K+ CURRENT | - |
dc.subject.keywordPlus | POTASSIUM CHANNEL | - |
dc.subject.keywordPlus | CARDIAC-MUSCLE | - |
dc.subject.keywordPlus | VOLTAGE-CLAMP | - |
dc.subject.keywordPlus | HYDROGEN-IONS | - |
dc.subject.keywordPlus | PH | - |
dc.subject.keywordPlus | ACIDOSIS | - |
dc.subject.keywordPlus | CA2+ | - |
dc.subject.keywordPlus | RECTIFICATION | - |
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