Fig. 6.

Representative time-course of the lumen negative transepithelial voltage (V_te) of the anterior midgut of larval (fourth instar) Aedes aegypti in the presence of hemolymph-side mosquito saline and luminal 100 mmol l^–1 NaCl. After mounting of the tissue, V_te declines but successively recovers after addition of serotonin (0.2 μmol l^–1) to the hemolymph-side bath and glutamine (10 mmol l^–1) to the luminal perfusate. Washout of serotonin in the presence of luminal glutamine indicates that the effect of luminal glutamine is stimulated by serotonin.