Measurements of electrical-potential difference (TEP) and Na+ efflux, across the integument have been made for Corophium volutator acclimated to 85 or 15%SW.
The TEP of acclimated animals in 85 or 15%SW is l.4mV or 11.1 mV respectively (haemolymph negative). For acclimated animals, unidirectional Na+ efflux is 154.3 nmol mg−1 body weight h−1 in 85%SW [efflux rate constant (k) = 0.70 h-1] and approximately 35.5 nmol mg−1 h−1 in 15%SW (k = 0.50h−1 in 10%SW).
The results indicate that Na+ and Cl−are passively distributed across the ion-permeable (gill) integument of acclimated animals in 85%SW, but that active uptake of Cl−, and possibly Na+ also, occurs across the gills of acclimated animals in 15%SW. The ion transport mechanisms appear to effect electroneutral transfers across the gill integumental epithelium.
Corophium volutator gill integument has a high permeability to ions; permeability to Na+(PNa) is 7.5×10−8ms−1, and the ratio PCl/PNa is 0.45, for animals acclimated to either salinity. The resistance of the gill epithelium of acclimated animals has been calculated to be 5.3×10−3Ωm2 and 2.0×10−2Ωm2 in 85 and 15%SW respectively.
Electrical-Potential Difference and Sodium Ion Fluxes across the Integument of Corophium Volutator (Crustacea; Amphipoda), a Euryhaline Hyperosmotic Regulator
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Peter M. Taylor; Electrical-Potential Difference and Sodium Ion Fluxes across the Integument of Corophium Volutator (Crustacea; Amphipoda), a Euryhaline Hyperosmotic Regulator. J Exp Biol 1 January 1985; 114 (1): 477–491. doi: https://doi.org/10.1242/jeb.114.1.477
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