Ca2+ flux through promiscuous cardiac Na+ channels:: Slip-mode conductance

被引:148
作者
Santana, LF
Gómez, AM
Lederer, WJ [1 ]
机构
[1] Univ Maryland, Dept Mol Biol & Biophys, 725 W Lombard St, Baltimore, MD 21201 USA
[2] Univ Maryland, Dept Physiol, Ctr Med Biotechnol, Baltimore, MD 21201 USA
[3] Univ Maryland, Sch Med, Baltimore, MD 21201 USA
关键词
D O I
10.1126/science.279.5353.1027
中图分类号
O [数理科学和化学]; P [天文学、地球科学]; Q [生物科学]; N [自然科学总论];
学科分类号
07 ; 0710 ; 09 ;
摘要
The tetrodotoxin-sensitive sodium ion (Na+) channel is opened by cellular depolarization and favors the passage of Na+ over other ions. Activation of the beta-adrenergic receptor or protein kinase A in rat heart cells transformed this Na+ channel into one that is promiscuous with respect to ion selectivity, permitting calcium ions (Ca2+) to permeate as readily as Na+. Similarly, nanomolar concentrations of cardiotonic steroids such as ouabain and digoxin switched the ion selectivity of the Na+ channel to this state of promiscuous permeability called slip-mode conductance. Slip-mode conductance of the Na+ channel can contribute significantly to local and global cardiac Ca2+ signaling and may be a general signaling mechanism in excitable cells.
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页码:1027 / 1033
页数:7
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