Key result
The steep extracellular K+ dependence of Kir2.1-mediated outward IK1 is driven by K+-dependent inhibition of outward IK1 by extracellular Na+ and Ca2+ via screening of local negative surface charges.
Extracellular Na+ and Ca2+ inhibit outward Kir2.1 currents by screening local negative surface charges, explaining the dependence of these currents on extracellular K+ concentration, which is relevant for understanding re-entrant ventricular arrhythmias.
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May inform IK1 behavior in hypokalemic arrhythmias; leaves open in vivo validation and clinical translation.
Chang et al. (2010) studied this question. Extracellular Na+ and Ca2+ was evaluated on Outward Kir2.1 current (IK1). The steep extracellular K+ dependence of Kir2.1-mediated outward IK1 is driven by K+-dependent inhibition of outward IK1 by extracellular Na+ and Ca2+ via screening of local negative surface charges.
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