Fig. 3. ∆pH_i amongst groups during the 0-Na⁺ phase of the ammonium prepulse technique. The highest ∆pHi is seen in colonocytes perfused with penG + arginine, followed by penG alone. A higher ∆pHi represents a greater degree of activation of the H⁺, K⁺ ATPase. The number of rats per group are as follows: Control, n=7; Pen G, n=9; Arginine, n=9; PenG + Arginine, n = 16; PenG + L-NAME, n = 7.