Figure 3. I_SC measurements in Ussing-chamber experiments with isolated colonic mucosa.

I_SC measurements in Ussing-chamber experiments with isolated colonic mucosa from normal mice (Fig. 3A–C), from NKCC1 (−/−) mice and from their NKCC1 (+/+) littermates (Fig. 3D and E). cAMP-dependent stimulation of I_SC (A) was inhibited to the same extent by 100 μm (not shown) or 500 μm bumetanide (B) as by 100 μm azosemide (C), and neither compound resulted in further I_SC inhibition after the other one was added (B and C). Furthermore, 100 μm azosemide had no effect on I_SC (D and E) or HCO₃⁻ flux (not shown) in NKCC1 (−/−) colon (n = 3–5).