Na+ fluxes across isolated perfused gills of the chinese crab Eriocheir sinensis
Péqueux, A.; Gilles, R. (1981). Na+ fluxes across isolated perfused gills of the chinese crab Eriocheir sinensis. J. Exp. Biol. 92(1): 173-186
In: The Journal of Experimental Biology. Cambridge University Press: London. ISSN 0022-0949; e-ISSN 1477-9145, more
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| Authors | | Top |
- Péqueux, A.
- Gilles, R., more
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| Abstract |
Sodium transport processes in the branchial epithelium of euryhaline crustaceans have been investigated using a perfused preparation of gills isolated from Chinese crabs Eriocheir sinensis acclimated to dilute (FW) and to concentrated (SW) media.The results clearly establish the existence of a functional difference between the different pairs of branchiae with respect to their participation in the regulation of the blood Na+ content.In FW-acclimated animals, the Na+ active uptake which counter-balances the salt loss along the concentration gradient is mostly achieved across the three posterior pairs of gills. Conversely, the Na+ fluxes measured in the three anterior pairs are essentially passive and carrier-mediated.Further characterization of the Na+ uptake system present in the posterior gills by means of inhibitors like ouabain and ethacrynic acid indicates the existence of at least two spatially separated components of the Na+ carrying system.It is shown that NH4+ may be used as co-ion for Na+ but that such a coupling can only account for a very small part of the Na+ actively transported inward. The existence of an electrogenic mechanism or of another coupled system has thus to be postulated but remains at present a matter of speculation.To study FW-to-SW and SW-to-FW acclimation, Na+ fluxes were measured in isolated gills of SW-acclimated crabs and of FW crabs perfused and incubated in SW conditions.During acclimation to SW the Na+ active uptake in the posterior gills is abolished primarily as a result of inhibition of the Na+ carrier activity. |
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