Parisi M, Gauna A, Rivas E
J Membr Biol. 1976 May;26(4):335-44. doi: 10.1007/BF01868881.
The water diffusional permeability, its activation energy and the lipid composition were studied in urinary bladders from toads adapted to different temperatures. It was observed that the unidirectional water flux greatly depends on the temperature at which the experiments are performed. This dependence is greater in the animals adapted to higher temperatures. Toads adapted to cold show strong reduction in the activation energy for water diffusion permeability (from 11.4+/-1.9 kcal-mol-1 to 4.4+/-1.1kcal-mol-1) and an increase of 30% in the amount of total lipids from bladder epithelial cells. There were no significant changes in the phospholipid/cholesterol ratio, composition of the parafinic chains or protein concentration between toads adapted to both temperatures. The possibility that water translocates through the mucosal border of the toad bladder by partitioning in the polar zone and diffusioning between the hydrocarbon chains of the membrane lipids and that cold adaptation would induce a stronger "packing" of lipids in the membrane is discussed.
对适应不同温度的蟾蜍膀胱的水扩散通透性、其活化能和脂质组成进行了研究。观察到单向水通量很大程度上取决于进行实验的温度。在适应较高温度的动物中，这种依赖性更大。适应寒冷的蟾蜍水扩散通透性的活化能大幅降低（从11.4±1.9千卡·摩尔⁻¹降至4.4±1.1千卡·摩尔⁻¹），膀胱上皮细胞总脂质含量增加30%。在适应两种温度的蟾蜍之间，磷脂/胆固醇比值、石蜡链组成或蛋白质浓度没有显著变化。讨论了水通过在极性区分配并在膜脂质的烃链之间扩散而穿过蟾蜍膀胱黏膜边界的可能性，以及寒冷适应会诱导膜中脂质更强“堆积”的可能性。
