Fig. 9.
Anion removal prevents lubiprostone-induced gland secretion. Bumetanide (Bm; 100 μM) and replacement of HCO3− by HEPES buffer were used to effectively remove anions from the basolateral face of epithelia suspended at an air-Krebs interface. Responses to 1 μM lubiprostone, applied basolaterally, in normal and ion-substituted tissues were compared. A shows secretion rates in a pair of pig preparations. B shows a summary of bumetanide-HEPES inhibition of lubiprostone responses in 2 sheep and 1 pig, stated as a percentage of the normal lubiprostone response. **Significant difference (P < 0.01).