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HCO3-stimulated CL efflux in the Gulf toadfish acclimated to sea water

✍ Scribed by Kormanik, Gregg A. ;Evans, David H.


Publisher
John Wiley and Sons
Year
1979
Tongue
English
Weight
308 KB
Volume
208
Category
Article
ISSN
0022-104X

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✦ Synopsis


Unidirectional efflux of Cl was examined in the Gulf toadfish, Opsanus beta, in artificial seawater solutions with modified concentrations of Cl and HCO3. Removal of Cl HCO3 reduced Cl efflux. Addition of HCO3 at typical seawater concentrations stimulated Cl efflux, independent of changes in the transepithelial potential. This active, HCO3-stimulated Cl efflux is saturable, with a Km of 2.4 mM, typical of the concentration of HCO3 found in sea water, and independent of external pH. Active extrusion of Cl offsets the net diffusional and oral gain of Cl faced by O. beta in sea water.