Ugolev A M, Metel'skii S T
Institute of Higher Nervous Activity and Neurophysiology, Academy of Sciences of the USSR, Moscow.
Biomed Sci. 1990;1(6):578-84.
Conditions in rat and turtle small intestine tissue where glucose and glycine transport are inhibited while glucose-induced Na+ transport is preserved are described. The generally accepted model for the Na(+)-dependent transporter (a single channel for the Na+ and nutrient) does not account for the data obtained from an analysis of the interaction between the transport of glucose, glycine, and Na+ at different temperatures and the effect of inhibitors on these processes. The phenomenon of uncoupling of Na+ and nutrient transport can best be described by a two-channel model with a gate mechanism. According to this model, the Na(+)-dependent transporter has at least two channels: one for Na+ and another for nutrients. The model provides for the passage of Na+ in both directions along a channel opened by glucose, and accounts for changes in the stoichiometric ratio of Na+: glucose transport. Experiments are reported that confirm these theoretical predictions.
本文描述了大鼠和龟小肠组织中的情况，其中葡萄糖和甘氨酸转运受到抑制，而葡萄糖诱导的Na⁺转运得以保留。关于Na⁺依赖性转运体（一种Na⁺和营养物质的单通道）的普遍接受的模型无法解释在不同温度下对葡萄糖、甘氨酸和Na⁺转运之间相互作用的分析所获得的数据，以及抑制剂对这些过程的影响。Na⁺与营养物质转运解偶联的现象最好用具有门控机制的双通道模型来描述。根据该模型，Na⁺依赖性转运体至少有两个通道：一个用于Na⁺，另一个用于营养物质。该模型允许Na⁺沿由葡萄糖打开的通道双向通过，并解释了Na⁺:葡萄糖转运化学计量比的变化。报道了证实这些理论预测的实验。
