Departamento de Morfologia, Universidade Federal do Amazonas, Avenida General Rodrigo Octávio Jordão Ramos, 3000. Coroado I, Manaus, AM, Brazil.
J Fish Biol. 2009 Mar;74(4):956-60. doi: 10.1111/j.1095-8649.2008.02156.x.
During low-water period, freshwater stingray Paratrygon aiereba collected in the whitewater (WW) of the River Amazon showed higher urea content, osmolality, Na(+) and Cl(-) concentrations in plasma and perivisceral fluid than those caught in blackwater (BW) of the River Negro. Gills and kidney Na(+)-K(+)-ATPase activities were significantly lower in WW than in BW fish. The high level of kidney Na(+)-K(+)-ATPase activity in P. aiereba may minimize ion loss and generate diluted solute-free urine in ion-poor BW environment.
在枯水期，在亚马孙河白水（WW）中收集的淡水黄貂鱼 Paratrygon aiereba 的血浆和围内脏液中的尿素含量、渗透压、Na(+)和 Cl(-)浓度高于在亚马孙河黑河（BW）中捕获的黄貂鱼。WW 中的鱼的鳃和肾脏 Na(+)-K(+)-ATP 酶活性明显低于 BW 中的鱼。P. aiereba 肾脏 Na(+)-K(+)-ATP 酶活性高可能会最大限度地减少离子损失，并在离子贫乏的 BW 环境中产生稀释的无溶质尿液。
