Fig. 4.

Effects of cell dialysis on I_K1,tail. A: cell dialysis at 35°C leads to quick and significant decrease in the amplitude of I_K1,tail (I_K1,tail^N). Because of the rapidity of the effect, ventricular myocytes were first voltage-clamped in the whole cell configuration at room temperature (RT), and the temperature was then increased to 35°C. Initial increase in I_K1,tail^N upon temperature step is likely due, at least in part, to temperature-dependent increase in I_K1 (Table 1). Mg²⁺ ions were omitted in the pipette solution. B: experiments similar to that in A were carried out at other temperatures. At RT, I_K1,tail^N declined only by ∼18% after 10 min of cell dialysis. See methods for detailed description of the meaning of Δt. C: inclusion of Mg²⁺ ions in the pipette solution had a protective effect on I_K1,tail^N at all temperatures. In B and C, n = 5–7.