Facilitated Transport of Glucose from Blood into Peripheral Nerve
Facilitated Transport of Glucose from Blood into Peripheral Nerve
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促进葡萄糖从血液转运至周围神经
DOI：
10.1111/j.1471-4159.1985.tb04087.x
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发表时间：
1985
影响因子：
4.7
通讯作者：
S. Rapoport
中科院分区：
文献类型：
--
作者：
E. Rechthand;Q. Smith;S. Rapoport
翻译后摘要：D-葡萄糖是周围神经能量代谢的主要底物。葡萄糖通过血-神经屏障的机制尚不清楚。在这项研究中，在麻醉大鼠原位灌注技术，检查单糖从血液到周围神经的运输。在未标记D-葡萄糖的不同灌注液浓度下，测量D-[14 C]葡萄糖、L-[14 C]葡萄糖和[14 C]3-O-甲基-D-葡萄糖穿过胫神经毛细血管的单向流入。随着D-葡萄糖灌注液浓度的增加，D-[14 C]葡萄糖和[14 C]3-O-甲基-D-葡萄糖的渗透性-表面积乘积（PA）降低，而L-[14 C]葡萄糖的PA保持不变。在灌注液中不存在添加的未标记D-葡萄糖的情况下，L-[14 C]葡萄糖的PA等于D-[14 C]葡萄糖的PA的五分之一。这些结果证明了葡萄糖转移的自饱和、竞争性抑制和立体特异性，并首次显示了哺乳动物外周神经毛细血管中D-单糖的单向易化转运机制。数据拟合模型为促进运输和被动扩散。D-葡萄糖内流饱和组分的半饱和常数和最大转运速率分别为23 ± 11 μmol ml-1和6.6 ± 3.2 × 10-3μmol ± s-1· g-1。不饱和葡萄糖内流常数为0.5 ± 0.1 × 10- 4s-1。在正常血糖浓度下，可饱和成分约占流入神经的总D-葡萄糖的80%。在麻醉大鼠中，D-葡萄糖的单向流入超过了周围神经对葡萄糖的利用率。
Abstract: D‐Glucose is the major substrate for energy metabolism in peripheral nerve. The mechanism of transfer of glucose across the blood–nerve barrier is unclarified. In this study an in situ perfusion technique was utilized, in anesthetized rats, to examine monosaccharide transport from blood into peripheral nerve. Unidirectional influxes of D‐[14C]glucose, L‐[14C]glucose, and [14C]3‐O‐methyl‐D‐glucose across capillaries of the tibial nerve were measured at different perfusate concentrations of unlabelled D‐glucose. The permeability‐surface area product (PA) for D‐[14C]glucose and [14C]3‐O‐methyl‐D‐glucose decreased, whereas the PA for L‐[14C]glucose remained constant, as the perfusate concentration of D‐glucose was increased. In the presence of no added unlabelled D‐glucose in the perfusate, the PA for L‐[14C]glucose equaled one‐fifth the PA for D‐[14C]glucose. These results demonstrate self‐saturation, competitive inhibition, and stereospecificity of glucose transfer, and for the first time show a unidirectional facilitated transport mechanism for D‐monosaccharides at capillaries of mammalian peripheral nerve. The data were fit to a model for facilitated transport and passive diffusion. The half‐saturation constant and maximal rate of transport for the saturable component of D‐glucose influx equaled 23 ± 11 μmol ml–1 and 6.6 ± 3.2 × 10–3μmol ± s–1· g–1, respectively. The constant of nonsaturable glucose influx equaled 0.5 ± 0.1 × 10–4 s–1. At normal plasma glucose concentrations, the saturable component comprises about 80% of total D‐glucose influx into nerve. In anesthetized rats unidirectional influx of D‐glucose exceeds, by a factor of about two, published rates of glucose utilization by peripheral nerve.