Skul'skiĭ I A, Burovina I V, Glaszunov V V
Zh Evol Biokhim Fiziol. 1976 Mar-Apr;12(2):105-12.
The in- and outflow of 204Tl, 86Rb and 137Cs in a snail brain was studied. The inward rate constants determined in the presence and without ouabain decreased as follows: Tl+ greater than Rb+ greater than Cs+. The inflow rate constants differed about 2-3 fold. Rates of leakage of the cations were nearly similar, so that Tl+ approximately or equal to Rb+ greater than Cs+. A Na ouabain-sensitive outward transport in a K-free medium containing 0.1-0.2 mM Tl was as high as that in the presence of 1.6 mM external K. A further increase of external Tl inhibited the ouabain-sensitive Na transport. The intracellular distribution of Tl studied by microprobe analysis was found to be similar to that of K. There was a close resemblance of the ouabain-sensitive K-transporting system in the snail brain cells and that in other types of cells including human red cells in their selectivity to Tl+, Rb+ and Cs+. On the contrary, a passive permeability of neurons to Tl+ being similar to that of muscle cells was about 50-100 times less than a Tl+ permeability of inexcitable red cell membrane.
研究了204Tl、86Rb和137Cs在蜗牛脑中的流入和流出情况。在有哇巴因和无哇巴因存在时测定的内向速率常数下降顺序如下：Tl+＞Rb+＞Cs+。流入速率常数相差约2 - 3倍。阳离子的泄漏速率几乎相似，因此Tl+≈Rb+＞Cs+。在含有0.1 - 0.2 mM Tl的无钾培养基中，哇巴因敏感的钠外向转运与存在1.6 mM外部钾时一样高。外部Tl的进一步增加会抑制哇巴因敏感的钠转运。通过微探针分析研究发现，Tl在细胞内的分布与K相似。蜗牛脑细胞中哇巴因敏感的钾转运系统与包括人类红细胞在内的其他类型细胞中该系统对Tl+、Rb+和Cs+的选择性非常相似。相反，神经元对Tl+的被动通透性与肌肉细胞相似，但比不可兴奋的红细胞膜对Tl+的通透性小约50 - 100倍。
