Characterization of copper transport in gill cells of a mangrove crab Ucides cordatus

Autor(es)

Sa, M. G. ^[1] ; Zanotto, F. P. ^{[2, 1]}

Afiliação do(s) autor(es)

^[1] Univ Sao Paulo, Dept Physiol, Biosci Inst, BR-05508900 Sao Paulo - Brazil

^[2] Univ Fed Sao Paulo, Escola Paulista Med, Dept Biophys, BR-04044020 Sao Paulo - Brazil

• Tipo de documento: Artigo Científico
• Fonte: AQUATIC TOXICOLOGY; v. 144, p. 275-283, NOV 15 2013.
• Citações Web of Science: 8

Resumo

The branchial epithelium of crustaceans is exposed to the environment and is the first site affected by metal pollution. The aim of this work was to characterize copper (Cu) transport using a fluorescent dye, Phen Green, in gill cells of a hypo-hyper-regulator mangrove crab Ucides cordatus. The results showed that added extracellular CuCl2 (0, 0.025, 0.150, 0.275, 0.550 and 1.110 mu M) showed typical Michaelis-Menten transport for Cu in anterior and posterior gill cells (V-max for anterior and posterior gills: 0.41 +/- 0.12 and 1.76 +/- 0.27 intracellular Cu in mu M x 22.10(4) cells(-1) x 300 s(-1) respectively and K-m values: 0.44 +/- 0.04 and 0.32 +/- 0.13 mu M, respectively). Intracellular Cu was significantly higher for posterior gill cells compared to anterior gill cells, suggesting differential accumulation for each gill type. Extracellular Ca at 20 mM decreased cellular Cu transport for both anterior and posterior gill cells. Nifedipine and verapamil, calcium channel inhibitors from plasma membrane, decreased Cu transport and affected K-m for both gills. These results could be due to a competition between Cu and Ca. Amiloride, a Na/Ca exchanger inhibitor, as well as bafilomycin, a proton pump inhibitor, caused a decrease of intracellular Cu compared to control. Ouabain and KB-R 7943, acting on Na homeostasis, similarly decreased intracellular Cu in both gill cells. Besides that, gill cells exposed to ATP and Cu simultaneously, showed an increase in intracellular copper, which was inhibited by vanadate, an inhibitor of P-type ATPase. These results suggest either the presence of a Cu-ATPase in crab gill cells, responsible for Cu influx, or the effect of a change in electrochemical membrane potential that could also drive Cu to the gill cell interior. Caffeine increased intracellular Cu, suggesting that intracellular Ca could be affecting Cu uptake. Overall the results show that copper uptake in gill cells of crabs is regulated by intracellular Ca, Ca channels and by Na exchangers. This is the first report of Cu transport characterization in whole gill cells of crabs. (C) 2013 Elsevier B.V. All rights reserved. (AU)

• Processo FAPESP: 09/15546-3 - Caracterização do transporte de cádmio em interação com o cálcio em células epiteliais de Ucides cordatus, um caranguejo de mangue
• Beneficiário: Flavia Pinheiro Zanotto
• Modalidade de apoio: Auxílio à Pesquisa - Regular