The Na(+)-dependence of Na(+)-activated K(+)-channels (IK(Na)) in guinea pig ventricular myocytes, is different in excised inside/out patches and cell attached patches.
Single Na(+)-activated K(+)-channels were recorded from intact guinea-pig ventricular myocytes perfused with Ca-free, Mg-free Tyrode, to increase [Na+]i. The activity of these channels increases with the time of perfusion with this solution and decreases when the bathing sodium is reduced. The activity of the Na(+)-activated K(+)-channel is greater in the cell attached patches than from excised cell free patches, at the same [Na+]. It is suggested that this K+ channel is significantly active in intact cells within the physiological range of [Na]i.
Rodrigo
G C
GC
University of Newcastle upon Tyne, Department of Physiological Sciences, Medical School, UK.
D000818:Animals; D004566:Electrodes; D006168:Guinea Pigs; D006352:Heart Ventricles / Q000166:cytology / Q000378:metabolism*; D066298:In Vitro Techniques; D009206:Myocardium / Q000166:cytology / Q000378:metabolism*; D015221:Potassium Channels / Q000378:metabolism*; D012964:Sodium / Q000502:physiology*
D015221:Potassium Channels; D012964:Sodium