| Literature DB >> 9512025 |
T Paquette1, J R Clay, A Ogbaghebriel, A Shrier.
Abstract
The effects of divalent cations on the E-4031-sensitive repolarization current (I(Kr)) were studied in single ventricular myocytes isolated from rabbit hearts. One group of divalent cations (Cd2+, Ni2+, Co2+, and Mn2+) produced a rightward shift of the I(Kr) activation curve along the voltage axis, increased the maximum I(Kr) amplitude (i.e., relieved the apparent inward rectification of the channel), and accelerated I(Kr) tail current kinetics. Another group (Ca2+, Mg2+ and Sr2+) had relatively little effect on I(Kr). The only divalent cation that blocked I(Kr) was Zn2+ (0.1-1 mM). Under steady-state conditions, Ba2+ caused a substantial block of I(K1) as previously reported. However, block by Ba2+ was time dependent, which precluded a study of Ba2+ effects on I(Kr). We conclude that the various effects of the divalent cations can be attributed to interactions with distinct sites associated with the rectification and/or inactivation mechanism of the channel.Entities:
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Year: 1998 PMID： 9512025 PMCID： PMC1299475 DOI： 10.1016/S0006-3495(98)77841-5
Source DB: PubMed Journal: Biophys J ISSN： 0006-3495 Impact factor: 4.033