Figure 2.
Leak currents depend on pHo in ventricular myocytes. Experiments similar to those in Fig. 1 were performed in several myocytes using either DHO (2 mM), strophanthidin (1 mM) or ouabain (2 mM) to inhibit Na/K pumps after exposure to the desired pHo. (A) Mean CS-sensitive current (normalized to cell capacitance) at indicated pH values is plotted as a function of voltage. Error bars represent the mean ± SE. (B) External pH dependence of the current at each voltage obtained from the average I/V curves in A. Lines represent the fit of a Hill equation to the average data with the following parameters and errors: shared nH = 1.8 ± 0.3, K0.5H (in μM) 0.41 ± 0.11 (−160 mV, squares), 0.49 ± 0.13 (−140 mV, circles), 0·65 ± 0.19 (−120 mV, triangles), 0.76 ± 0.24 (−100 mV, diamonds), 0.99 ± 0.37 (−80 mV, side triangles), 1.30 ± 0.54 (−60 mV, hexagons), and 2.05 ± 1.3 (−40 mV, stars). To see this figure in color, go online.