title: Environmental salinity and sodium and chloride exchanges across the gill of Tilapia mossambica.
abstract: 10 Freshwater-(FW)-adapted, one-third seawater (1/3 SW)-adapted and seawater (SW) adapted Tilapia mossambica were compared for their branchial Na+ influx and efflux as well as Cl- efflux. Na+ and Cl- effluxes were identical. Rates of effluxes were in 1/3 SW- and in SW-adapted fish 10 times and 200 times higher respectively than in FW specimens. 20 Shock due to handling and transfer to small experimental chambers induced, within 20 to 45 min., a considerable increase in Na+ efflux and a more discrete augmentation of the Na+ influx. 30 Branchial Mg++-and Na+-K+ activated ATPase activities increased significantly upon adaptation from FW to 1/3 SW. No significant increase was apparent upon adaptation from 1/3 SW to SW. 40 The trans-branchial potential observed in SW Tilapia resembled the pattern previously described in other species of teleosts.
mesh_terms: D000222:Adaptation, Physiological; D000251:Adenosine Triphosphatases / Q000378:metabolism; D000818:Animals; D001693:Biological Transport, Active; D002712:Chlorides / Q000378:metabolism*; D005260:Female; D005399:Fishes / Q000502:physiology*; D005618:Fresh Water; D005880:Gills / Q000378:metabolism*; D008274:Magnesium / Q000494:pharmacology; D008297:Male; D008564:Membrane Potentials; D008861:Microsomes / Q000201:enzymology; D008928:Mitochondria / Q000201:enzymology; D011188:Potassium / Q000494:pharmacology; D012623:Seawater; D012964:Sodium / Q000378:metabolism* / Q000494:pharmacology; D013312:Stress, Physiological; D014867:Water / Q000378:metabolism; D014882:Water-Electrolyte Balance
chemical_list: D002712:Chlorides; D014867:Water; D012964:Sodium; D000251:Adenosine Triphosphatases; D008274:Magnesium; D011188:Potassium