Effect of extracellular HCO₃ in the presence and absence of HOE694 on intracellular pH change in crypt glands from proximal colon.

<p>Images of a crypt gland before [<b>A</b>] and after BCECF loading [<b>B</b>]. The BCECF loaded crypts were excited at 490 nm and 440 nm and the emission signal was monitored at 535 nm to derive intracellular pH (pHi). [<b>C</b>] Under basal condition, bath HCO₃ increased pHi, while the increased pHi was completely reversed by HCO₃ removal. [<b>D</b>] In the presence of amiloride, bath HCO₃ reduced the pHi, while the reduced pHi was partially reversed by HCO₃ removal. [<b>E</b>] In the presence of HOE694, bath HCO₃ increased pHi, while the increased pHi was completely reversed by HCO₃ removal. Typical tracing presented is representative of observations in 4 different crypts from 5 different rats.