Figure 8.

Astrocytes in Kir4.1−/−;Tg(hGFAP/EGFP) mice (P9) in situ lack Ba²⁺-sensitive currents. A, Membrane currents before (left) and in the presence of (right) Ba²⁺ (100 μm) were elicited as described in Figure 1. B, The Ba²⁺-sensitive component was isolated through a subtraction protocol. C, Mean (9 cells) I/V relationships were determined before (filled triangles) and during (open circles) application of Ba²⁺ (100 μm). D, The membrane was repetitively clamped between −160 and +100 mV for 100 ms, separated by 100 ms (holding potential, −70 mV; see inset), and 100 μm Ba²⁺ was added via the bath as indicated, confirming that Ba²⁺ had no effect on current amplitudes.