变温动物晶状体的研究。I. 虹鳟和大鼠晶状体中阳离子维持系统的比较研究。

Exp Eye Res. 1985 Aug;41(2):171-8. doi: 10.1016/0014-4835(85)90021-1.

The response of the poikilothermal lens to various incubation temperatures in vitro was compared with that of the homothermal lens. The rainbow trout lens was used as the poikilothermal lens and the rat lens as the homothermal lens. In contrast to rat lenses, cataract developed at 37 degrees C in rainbow trout lenses, which was called 'warm cataract'. Warm cataract developed not only when lenses were incubated in vitro but also when rainbow trout were kept in water at 37 degrees C. Water, Na+, Ca2+ and insoluble protein increased and K+ and Mg2+ decreased in warm cataract lenses, but GSH and soluble protein sulfhydryl levels did not change. This cataract was irreversible after only 5 min incubation at 37 degrees C. On the other hand, rainbow trout lenses remained transparent without the change of cation balance at 0-25 degrees C while cold cataract developed in rat lenses. Na,K-ATPase activity was detected at 0 degrees C in rainbow trout lens homogenates, but not in rat lens homogenates. Na+-K+ ratio (Na+/K+) increased when the rainbow trout lens was treated with ouabain at 0 degrees C. In the rainbow trout lens, lactic acid was produced continuously for 30 days at 0 degrees C while it was not in the rat lens between 1 hr and 10 days after. These results strongly suggest that Na,K-ATPase acts as a cation pump at 0 degrees C and that ATP is supplied by glycolysis in the rainbow trout lens in order to maintain the transparency. The above results also suggest that enzymes and membrane structures in rainbow trout lens are adapted to a cold-temperature habitat and that Na,K-ATPase and anaerobic glycolysis are important for the maintenance of lens transparency at low temperatures.

将变温动物晶状体与恒温动物晶状体在体外对不同孵育温度的反应进行了比较。以虹鳟鱼晶状体作为变温动物晶状体，大鼠晶状体作为恒温动物晶状体。与大鼠晶状体不同，虹鳟鱼晶状体在37℃时会发生白内障，这种白内障被称为“温热性白内障”。温热性白内障不仅在晶状体体外孵育时出现，当虹鳟鱼饲养在37℃的水中时也会发生。温热性白内障晶状体中的水、Na⁺、Ca²⁺和不溶性蛋白质增加，而K⁺和Mg²⁺减少，但谷胱甘肽（GSH）和可溶性蛋白质巯基水平没有变化。在37℃孵育仅5分钟后，这种白内障就不可逆转。另一方面，虹鳟鱼晶状体在0 - 25℃时保持透明，阳离子平衡无变化，而大鼠晶状体则出现了冷性白内障。在0℃时，虹鳟鱼晶状体匀浆中检测到钠钾ATP酶（Na,K - ATPase）活性，而大鼠晶状体匀浆中未检测到。当虹鳟鱼晶状体在0℃用哇巴因处理时，Na⁺ - K⁺比率（Na⁺/K⁺）增加。在虹鳟鱼晶状体中，在0℃时乳酸持续产生30天，而大鼠晶状体在1小时至10天后则不产生。这些结果有力地表明，Na,K - ATPase在0℃时作为阳离子泵起作用，并且为了维持透明度，虹鳟鱼晶状体中的ATP由糖酵解提供。上述结果还表明，虹鳟鱼晶状体中的酶和膜结构适应低温环境，并且Na,K - ATPase和无氧糖酵解对于在低温下维持晶状体透明度很重要。