title: Pharmacological characterisation of apical Na+ and Cl- transport mechanisms of the anal papillae in the larval mosquito Aedes aegypti.
abstract: The anal papillae of freshwater mosquito larvae are important sites of NaCl uptake, thereby acting to offset the dilution of the hemolymph by the dilute habitat. The ion-transport mechanisms in the anal papillae are not well understood. In this study, the scanning ion-selective electrode technique (SIET) was utilized to measure ion fluxes at the anal papillae, and pharmacological inhibitors of ion transport were utilized to identify ion-transport mechanisms. Na(+) uptake by the anal papillae was inhibited by bafilomycin and phenamil but not by HMA. Cl(-) uptake was inhibited by methazolamide, SITS and DIDS but not by bafilomycin. H(+) secretion was inhibited by bafilomycin and methazolamide. Ouabain and bumetanide had no effect on NaCl uptake or H(+) secretion. Together, the results suggest that Na(+) uptake at the apical membrane occurs through a Na(+) channel that is driven by a V-type H(+)-ATPase and that Cl(-) uptake occurs through a Cl(-)/HCO(3)(-) exchanger, with carbonic anhydrase providing H(+) and HCO(3)(-) to the V-type H(+)-ATPase and exchanger, respectively.
authors.affiliation: Department of Biology, York University, Toronto, ON, Canada.
authors.forename: Olimpia
authors.initials: O
authors.lastname: Del Duca
authors.forename: Azadeh
authors.initials: A
authors.lastname: Nasirian
authors.forename: Vladimir
authors.initials: V
authors.lastname: Galperin
authors.forename: Andrew
authors.initials: A
authors.lastname: Donini
mesh_terms: D000330:Aedes / Q000187:drug effects / Q000378:metabolism*; D000584:Amiloride / Q000031:analogs & derivatives / Q000494:pharmacology; D001003:Anal Canal / Q000187:drug effects / Q000378:metabolism*; D000818:Animals; D002034:Bumetanide / Q000494:pharmacology; D002256:Carbonic Anhydrases / Q000378:metabolism; D002712:Chlorides / Q000378:metabolism*; D017136:Ion Transport / Q000187:drug effects; D017736:Ion-Selective Electrodes; D007814:Larva / Q000187:drug effects / Q000378:metabolism; D018942:Macrolides / Q000494:pharmacology; D008704:Methazolamide / Q000494:pharmacology; D008839:Microelectrodes; D008954:Models, Biological; D010042:Ouabain / Q000494:pharmacology; D012964:Sodium / Q000378:metabolism*; D028021:Sodium-Potassium-Chloride Symporters / Q000378:metabolism; D000254:Sodium-Potassium-Exchanging ATPase / Q000037:antagonists & inhibitors; D025262:Vacuolar Proton-Translocating ATPases / Q000037:antagonists & inhibitors
chemical_list: D002712:Chlorides; D018942:Macrolides; D028021:Sodium-Potassium-Chloride Symporters; D002034:Bumetanide; C057360:5-(N,N-hexamethylene)amiloride; C047088:phenylamil; D010042:Ouabain; D000584:Amiloride; C040929:bafilomycin A1; D012964:Sodium; D025262:Vacuolar Proton-Translocating ATPases; D002256:Carbonic Anhydrases; D000254:Sodium-Potassium-Exchanging ATPase; D008704:Methazolamide