FIGURE 7.

Changes in normalized furaptra R (A) and series resistance (B) measured in the cells internally perfused with the pipette solution containing 145 mM [Cs⁺] and 0 mM [K⁺] (145 Cs solution, Table 1) through the cell membrane permeabilized with amphotericin B. The indicator-loaded cells were incubated in the Ca-free Tyrode's solution, and a GΩ-seal was formed with the pipette containing amphotericin B. When series resistance dropped and approached 20 MΩ in 10–30 min, the bathing solution was changed from the Ca-free Tyrode's solution to the 0 K-0.5 Na solution (at time zero on the abscissa) as indicated at the top. In A and B, values of normalized furaptra R measured before (○) and after (•) GΩ-seal formation (A) and series resistance values (B, ▪) are plotted as a function of time after extracellular perfusion with the 0 K-0.5 Na solution. The holding potential was initially −83 mV and was set at −13 mV throughout the measurement run. Points obtained by scaling solid circles by a factor of 0.946 are also shown in A (x's). Each symbol represents the mean ± SE from five cells.