DC Field | Value | Language |
---|---|---|
dc.contributor.author | Ho, WK | ko |
dc.contributor.author | Kim, Injune | ko |
dc.contributor.author | Lee, CO | ko |
dc.contributor.author | Earm, YE | ko |
dc.date.accessioned | 2013-03-03T07:33:12Z | - |
dc.date.available | 2013-03-03T07:33:12Z | - |
dc.date.created | 2012-02-06 | - |
dc.date.created | 2012-02-06 | - |
dc.date.issued | 1998-03 | - |
dc.identifier.citation | JOURNAL OF PHYSIOLOGY-LONDON, v.507, no.3, pp.631 - 638 | - |
dc.identifier.issn | 0022-3751 | - |
dc.identifier.uri | http://hdl.handle.net/10203/77791 | - |
dc.description.abstract | 1. We expressed the human eag-related gene (HERG), which is known to encode the delayed rectifier K+ current (I-Kr) in cardiac muscle, in Xenopus oocytes. Using a two-microelectrode voltage clamp technique, the effect of external Ca2+ and Mg2+ on the HERG current (I-HERG) was investigated. 2. When [Ca2+](o) was increased, the amplitude of outward I-HERG elicited by depolarization decreased, and the rate of current onset slowed. The rate of current decay observed on repolarization was greatly accelerated. The threshold and fully activated potential of I-HERG shifted to a more positive potential. On the other hand, the inactivation property represented by the negative slope of the I-V curve and the instantaneous conductance of I-HERG were little affected by [Ca2+](o). 3. The effect of [Ca2+](o) on I-HERG can be interpreted using the channel blockade model. The blockade is voltage dependent; smaller dissociation constants (K-M) at more negative potentials indicate that block is facilitated by hyperpolarization. K-M changes e-fold for 14.5 mV and the fractional electrical distance of the binding site calculated from this value is 0.86. 4. Blockade by a low concentration of Ca2+ (0.5 mM) was inhibited by increasing [K+](o) (from 2 to 20 mM), whereas blockade by a high concentration of Ca2+ (5 mM) was not affected by varying [K+](o), indicating that there is competition between permeating ions and blocking ions. 5. The effect of [Mg2+](o) on I-HERG was qualitatively similar to that of [Ca2+](o), but the potency was lower. 6. These results suggest that external Ca2+ and Mg2+ block the HERG channel in a voltage-and time-dependent manner, resulting in a voltage dependence which has been regarded as a property of the activation gate. | - |
dc.language | English | - |
dc.publisher | CAMBRIDGE UNIV PRESS | - |
dc.subject | POTASSIUM CHANNEL | - |
dc.subject | DIVALENT-CATIONS | - |
dc.subject | SINOATRIAL NODE | - |
dc.subject | K+ CURRENT | - |
dc.subject | RECTIFICATION | - |
dc.subject | CONDUCTANCE | - |
dc.subject | RECTIFIER | - |
dc.subject | MODULATION | - |
dc.subject | MECHANISM | - |
dc.subject | NEURONS | - |
dc.title | Voltage-dependent blockade of HERG channels expressed in Xenopus oocytes by external Ca2+ and Mg2+ | - |
dc.type | Article | - |
dc.identifier.wosid | 000072902500002 | - |
dc.identifier.scopusid | 2-s2.0-0032521120 | - |
dc.type.rims | ART | - |
dc.citation.volume | 507 | - |
dc.citation.issue | 3 | - |
dc.citation.beginningpage | 631 | - |
dc.citation.endingpage | 638 | - |
dc.citation.publicationname | JOURNAL OF PHYSIOLOGY-LONDON | - |
dc.identifier.doi | 10.1111/j.1469-7793.1998.631bs.x | - |
dc.contributor.localauthor | Kim, Injune | - |
dc.contributor.nonIdAuthor | Ho, WK | - |
dc.contributor.nonIdAuthor | Lee, CO | - |
dc.contributor.nonIdAuthor | Earm, YE | - |
dc.type.journalArticle | Article | - |
dc.subject.keywordPlus | POTASSIUM CHANNEL | - |
dc.subject.keywordPlus | DIVALENT-CATIONS | - |
dc.subject.keywordPlus | SINOATRIAL NODE | - |
dc.subject.keywordPlus | K+ CURRENT | - |
dc.subject.keywordPlus | RECTIFICATION | - |
dc.subject.keywordPlus | CONDUCTANCE | - |
dc.subject.keywordPlus | RECTIFIER | - |
dc.subject.keywordPlus | MODULATION | - |
dc.subject.keywordPlus | MECHANISM | - |
dc.subject.keywordPlus | NEURONS | - |
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