Figure 2. Current traces in low symmetrical [NH4+] or [Tl+].

A, inward currents recorded at -140 mV in 3 mm (continuous line) and 10 mm symmetrical [NH4+] (dotted line). B, inward currents recorded at -140 mV in 3 mm (continuous line) and 10 mm symmetrical [Tl+] (dotted line). Current amplitudes were normalized to 1, and the zero current level was offset for comparison and clarity.