Iwata S
Curr Eye Res. 1985 Apr;4(4):441-6. doi: 10.3109/02713688509025158.
Membrane response to the various temperatures as one of the external factors was investigated in the lenses of the poikilothermal animal and the homothermal animal. The rainbow trout lens was used as the poikilothermal material and the rat lens as the homothermal material. The rainbow trout lens maintained in vitro its transparency without the changes of cation balance at 0 degrees C - 25 degrees C, while cold cataract developed in the rat lens under the same conditions. Na, K-ATPase activity was detected at 0 degrees C in rainbow trout lens but it was not detected in the rat lens. Lactic acid in the rainbow trout lens was produced for 30 successive days at 0 degrees C, while that in the rat lens was not produced. The cataract developed at 37 degrees C in rainbow trout lens, which we called "warm cataract." Warm cataract developed not only when the lens was incubated in vitro but also when rainbow trout was kept in fresh water at 37 degrees C. Significant differences were detected in components of membrane lipids in the rainbow trout lenses compared to bovine lenses as the mammalian lens. The cholesterol/phospholipid ratio in the trout lens membrane was lower than that in bovine lens. This suggests that a poikilothermal animal lens can maintain the membrane fluidity at low temperatures. These results might suggest that the membrane characteristics in the rainbow trout lens play a role to maintain its transparency at low temperatures.
作为外部因素之一，研究了变温动物和恒温动物晶状体对不同温度的膜反应。虹鳟鱼晶状体用作变温材料，大鼠晶状体用作恒温材料。虹鳟鱼晶状体在体外于0℃ - 25℃下保持透明，阳离子平衡无变化，而在相同条件下大鼠晶状体出现冷性白内障。虹鳟鱼晶状体在0℃时检测到钠钾ATP酶活性，而大鼠晶状体未检测到。虹鳟鱼晶状体在0℃下连续30天产生乳酸，而大鼠晶状体未产生。虹鳟鱼晶状体在37℃时出现白内障，我们称之为“热性白内障”。热性白内障不仅在晶状体体外培养时出现，当虹鳟鱼置于37℃的淡水中时也会出现。与作为哺乳动物晶状体的牛晶状体相比，虹鳟鱼晶状体的膜脂成分存在显著差异。虹鳟鱼晶状体膜中的胆固醇/磷脂比率低于牛晶状体。这表明变温动物的晶状体能够在低温下维持膜流动性。这些结果可能表明虹鳟鱼晶状体的膜特性在维持其低温下的透明度方面发挥作用。
