Figure 4. Effect of bumetanide on mucus release.

Application of NKCC inhibitor bumetanide (circles) to the basolateral side to inhibit fluid secretion consistently decreased stimulated mucus release compared with control without inhibitor (x’s). Mucus release was significantly lower with the inhibitor with each agonist as determined by each assay: PGE₂ (A and B) and 5-HT (C and D). (A) n = 3, P = 0.041. (B) n = 4, P = 0.003. (C) n = 3, P = 0.039. (D) n = 4, P = 0.036. All segments were bathed continuously in HCO₃^– Ringer solution. Samples were assayed by PAS and lectin binding as noted in Figure 2. Data shown are mean ± SEM.