Figure 1. High K⁺ diet increases Ba²⁺-sensitive K⁺ secretion in mouse distal colon.

A, two original Ussing chamber traces are depicted, the upper one is from a control animal and the lower from a mouse fed a high K⁺ diet. The figure shows the resting and luminal Ba²⁺ and the luminal ionomycin-induced transepithelial voltage (V_te) changes in the continuous presence of luminal amiloride (100 μm). The upper line indicates V_te and the bandwidth of voltage deflections reflects the transepithelial resistance (R_te, see Methods). After testing the resting luminal Ba²⁺ effect the tissue was washed and the experiment continued to quantify the Ba²⁺ after addition of luminal ionomycin. B, summary of calculated Ba²⁺-sensitive short-circuit current. *Statistically significant difference between animals of a normal and high K⁺ diet. ‡Significant differences in the paired controls.