||Bossus Maryline1, 2, Charmantier Guy1, 2, Blondeau-Bidet Eva1, 2, Valletta Bianca1, Boulo Viviane1, Lorin-Nebel Catherine1, 2
||1 : IFREMER, Equipe Adaptat Ecophysiol & Ontogenese, UMR5119, EcoSyM,CNRS,IRD,UM2,UM1, F-34095 Montpellier 05, France.
||Journal Of Comparative Physiology B-biochemical Systemic And Environmental Physiology (0174-1578) (Springer Heidelberg), 2013-07 , Vol. 183 , N. 5 , P. 641-662
|WOS© Times Cited
||ClC-3 chloride channel, Na+/K+-ATPase, Dicentrarchus labrax, Osmoregulation, Osmosensing
||Dicentrarchus labrax migrates between sea (SW), brackish and fresh water (FW) where chloride concentrations and requirements for chloride handling change: in FW, fish absorb chloride and restrict renal losses; in SW, they excrete chloride. In this study, the expression and localization of ClC-3 and Na+/K+-ATPase (NKA) were studied in fish adapted to SW, or exposed to FW from 10 min to 30 days. In gills, NKA-alpha 1 subunit expression transiently increased from 10 min and reached a stabilized intermediate expression level after 24 h in FW. ClC-3 co-localized with NKA in the basolateral membrane of mitochondria-rich cells (MRCs) at all conditions. The intensity of MRC ClC-3 immunostaining was significantly higher (by 50 %) 1 h after the transfer to FW, whereas the branchial ClC-3 protein expression was 30 % higher 7 days after the transfer as compared to SW. This is consistent with the increased number of immunopositive MRCs (immunostained for NKA and ClC-3). However, the ClC-3 mRNA expression was significantly lower in FW gills. In the kidney, after FW transfer, a transient decrease in NKA-alpha 1 subunit expression was followed by significantly higher stable levels from 24 h. The low ClC-3 protein expression detected at both salinities was not observed by immunocytochemistry in the SW kidney; ClC-3 was localized in the basal membrane of the collecting ducts and tubules 7 and 30 days after transfer to FW. Renal ClC-3 mRNA expression, however, seemed higher in SW than in FW. The potential role of this chloride channel ClC-3 in osmoregulatory and osmosensing mechanisms is discussed.
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