title: Characterization of cadmium plasma membrane transport in gills of a mangrove crab Ucides cordatus.
abstract: Membrane pathway for intracellular cadmium (Cd(2+)) accumulation is not fully elucidated in many organisms and has not been studied in crab gill cells. To characterize membrane Cd(2+) transport of anterior and posterior gill cells of Ucides cordatus, a hypo-hyper-regulating crab, a change in intracellular Cd(2+) concentration under various experimental conditions was examined by using FluoZin, a fluorescent probe. The membrane Cd(2+) transport was estimated by the augmentation of FluoZin fluorescence induced by extracellular application of CdCl2 and different inhibitors. Addition of extracellular calcium (Ca(2+)) to the cells affected little the fluorescence of FluoZin, confirming that Cd(2+) was the main ion increasing intracellular fluorescence. Ca(2+) channels blockers (nimodipine and verapamil) decreased Cd(2+) influx as well as vanadate, a Ca(2+)-ATPase blocker. Chelating intracellular Ca(2+) (BAPTA) decreased Cd(2+) influx in gill cells, while increasing intracellular Ca(2+) (caffeine) augmented Cd influx. Cd(2+) and ATP added at different temporal conditions were not effective at increasing intracellular Cd(2+) accumulation. Ouabain (Na(+)/K(+)-ATPase inhibitor) increased Cd(2+) influx probably through a change in intracellular Na and/or a change in cell membrane potential. Routes of Cd(2+) influx, a non-essential metal, through the gill cell plasma membrane of crabs are suggested.
authors.affiliation: Instituto de Biociências, Departamento de Fisiologia, Universidade de São Paulo, Rua do Matão, Travessa 14, #101, São Paulo 05508-900, SP, Brazil.
authors.forename: P
authors.initials: P
authors.lastname: Ortega
authors.affiliation: Instituto de Biociências, Departamento de Fisiologia, Universidade de São Paulo, Rua do Matão, Travessa 14, #101, São Paulo 05508-900, SP, Brazil.
authors.forename: M R
authors.initials: MR
authors.lastname: Custódio
authors.affiliation: Instituto de Biociências, Departamento de Fisiologia, Universidade de São Paulo, Rua do Matão, Travessa 14, #101, São Paulo 05508-900, SP, Brazil; Departamento de Biofísica, Escola Paulista de Medicina, Universidade Federal de São Paulo, Rua Três de Maio 100, São Paulo 04044-020, Brazil. Electronic address: fzanotto@usp.br.
authors.forename: F P
authors.initials: FP
authors.lastname: Zanotto
mesh_terms: D000818:Animals; D001692:Biological Transport / Q000187:drug effects; D003386:Brachyura / Q000187:drug effects / Q000378:metabolism*; D002104:Cadmium / Q000378:metabolism* / Q000633:toxicity; D002110:Caffeine / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism; D002121:Calcium Channel Blockers / Q000494:pharmacology; D002462:Cell Membrane / Q000378:metabolism*; D002470:Cell Survival; D002614:Chelating Agents / Q000494:pharmacology; D004533:Egtazic Acid / Q000031:analogs & derivatives / Q000494:pharmacology; D005453:Fluorescence; D005456:Fluorescent Dyes / Q000378:metabolism; D005880:Gills / Q000187:drug effects / Q000378:metabolism; D017136:Ion Transport / Q000187:drug effects; D009553:Nimodipine / Q000494:pharmacology; D014638:Vanadates / Q000494:pharmacology; D014700:Verapamil / Q000494:pharmacology; D014874:Water Pollutants, Chemical / Q000378:metabolism* / Q000633:toxicity
chemical_list: D002121:Calcium Channel Blockers; D002614:Chelating Agents; D005456:Fluorescent Dyes; D014874:Water Pollutants, Chemical; D002104:Cadmium; D002110:Caffeine; D014638:Vanadates; D004533:Egtazic Acid; D009553:Nimodipine; D014700:Verapamil; C025603:1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid; D002118:Calcium
keywords: Cadmium transport; Calcium channel blockers; Cell transport inhibitors; FluoZin; Gill cells; Ucides cordatus