Previously, we have demonstrated that such secondary metabolites as phosphoethanolamine (PE) and phosphoserine (PS) are low-temperature adaptogens specific to the brain of freshwater fish, in contrast to taurine which serves as an adaptogen in fish muscles and blood plasma. Here, we carry on investigating the role of PE, PS, taurine and proteinogenic amino acids in adaptation of poikilothermic animals to low temperatures. PE and PS were discovered in the brain of the frog Rana temporaria, and their pools were shown to increase by the onset of hibernation compared to the summer period almost in a similar manner (PE—from 0.22 to 1.65, PS—from 0.29 to 1.98 µmol/g wet weight). Unlike the fish brain, in the R. temporaria brain, the PE/PS ratio was almost indistinguishable in the winter compared to the summer. In contrast to fish, in the R. temporaria brain, the taurine level increased from 0.77 µmol/g in the summer to 1.37 µmol/g in the winter. The level of aspartic acid, which was missing in the fish brain during the winter, in the R. temporaria brain sharply increased by the onset of hibernation from 0.86 to 4.60 µmol/g. Thus, there is ground to believe that such secondary metabolites as PE, PS, taurine and proteinogenic aspartic acid play the role of low-temperature adaptogens in the brain of anuran amphibians.

中文翻译：

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蛙蛙脑中的次级代谢产物和天冬氨酸作为低温适应原

以前，我们已经证明，磷酸乙醇胺 (PE) 和磷酸丝氨酸 (PS) 等次级代谢物是淡水鱼大脑特有的低温适应原，而牛磺酸则是鱼类肌肉和血浆中的适应原。在这里，我们继续研究 PE、PS、牛磺酸和蛋白氨基酸在变温动物适应低温中的作用。在青蛙 Rana temporaria 的大脑中发现了 PE 和 PS，与夏季相比，它们的池在冬眠开始时以几乎类似的方式增加（PE——从 0.22 到 1.65，PS——从 0.29 到 1.98 µmol/g 湿重）。与鱼脑不同，在 R. temporaria 脑中，与夏季相比，冬季的 PE/PS 比率几乎无法区分。与鱼相反，在 R. temporaria 大脑中，牛磺酸水平从夏季的 0.77 µmol/g 增加到冬季的 1.37 µmol/g。冬眠期间鱼脑中天冬氨酸的含量随着冬眠开始而急剧增加，从 0.86 微摩尔/克增加到 4.60 微摩尔/克。因此，有理由相信诸如 PE、PS、牛磺酸和蛋白质天冬氨酸等次生代谢物在无尾两栖动物的大脑中发挥低温适应原的作用。