Figure 3

Whole-cell patch clamp currents with only Na⁺ or Li⁺ as the major permeant ions. The compositions of the bath perfusates are indicated by the horizontal bars and the colors of the bars are identical to the colors in the corresponding graphs. A) Representative continuous recording in symmetrical Na⁺-rich solutions (B2, P2; left panel) and Li⁺-rich solutions (B4, P2; right panel). Voltage step protocols were applied every 5.3 seconds with holding at 0 mV and steps from +100 mV to -100 mV in 20 mV decrements. Individual step responses are shown in the lower panels and their locations within the continuous trace are indicated by the numbers in parentheses. B) Representative current-voltage (I-V) relationships of the whole cell currents in the presence and absence of Benzamil (1 μM) at steady state (near 200 ms). The I-V relationship in Li⁺ bath was qualitatively similar to that in Na⁺ bath, as was the response to benzamil (1 μM).C) Summary bar graph of the currents at -100 mV in Li⁺-rich bath and Na⁺-rich pipette solutions (B4, P2).