Figure 6. Mean lumen negative transepithelial voltages (V_te; - S.E.M.) of 6 anterior midguts stimulated with serotonin (0.2 μmol l⁻¹) in presence (grey bar) and absence (white bar) of luminal methazolamide (200 μmol l⁻¹), and photographs of a representative preparation of the anterior midgut of larval (4^th instar) Aedes aegypti identical times after perfusion stop in presence (right) and absence (left) of luminal methazolamide (200 μmol l⁻¹). Before V_te and alkalinization after the influence of methazolamide were recorded, the tissues were exposed 10–15 minutes to the drug in the luminal perfusate.