Fig. 4.

Effects of luminal Zn²⁺ on pH_i at pH_L 10, on the transepithelial voltage (V_te), and on luminal alkalinization. (A) Effect of luminal ZnCl₂ (10 μmol l^–1) on the rate of pH_i alkalinization after switching to pH_L 10 in the presence of serotonin (means + s.e.m.). Control: 41 areas of interest from four different tissues. In the presence of Zn²⁺: 22 areas of interest from three different tissues. (B) Average lumen-negative transepithelial voltage (V_te, means – s.e.m.) of five isolated and perfused anterior midgut preparations of larval (4th instar) Aedes aegypti in the presence and absence of ZnCl₂ (10 μmol l^–1), and photographs of a representative preparation of the anterior midgut of larval 4th instar Aedes aegypti at identical times after perfusion stop in the presence (right) and absence (left) of ZnCl₂ (10 μmol l^–1).