Shin W W, Fong W F, Pang S F, Wong P C
J Neurochem. 1985 Apr;44(4):1056-9. doi: 10.1111/j.1471-4159.1985.tb08724.x.
Transport of polyamines across the blood-brain barrier of adult rats was examined by measuring the amount of radioactivity that reached the forebrain 5 s after a "bolus" intracarotid injection. The values were expressed by the brain uptake index (BUI), which is the percentage of material transported in relation to freely diffusible water in a single passage through the brain. Transport was restricted as indicated by the respective BUI values, presented as means +/- SD (number of animals): putrescine, 5.3 +/- 0.8 (11); spermidine, 6.1 +/- 1.3 (7); and spermine, 5.8 +/- 0.5 (4). A kinetic study of the transport of [14C]putrescine showed that transport due to passive diffusion accounted for the majority of the observed influx (66% at 1 mM putrescine). However, a small saturable component exists with a Km value of 4-5 mM and a Vmax of 30 nmol X min-1 X g-1. This Km value is considerably higher than the circulating levels of the polyamine in the normal mature animal, and thus is unlikely to be of physiological significance. Competition studies indicated that putrescine does not interact with carriers for adenosine, arginine, choline, or leucine.
通过测量成年大鼠“团注”颈内动脉注射后5秒到达前脑的放射性量，研究了多胺穿过血脑屏障的情况。这些值用脑摄取指数（BUI）表示，BUI是单次通过大脑时运输的物质相对于自由扩散水的百分比。如各自的BUI值所示，运输受到限制，以平均值±标准差（动物数量）表示：腐胺，5.3±0.8（11）；亚精胺，6.1±1.3（7）；精胺，5.8±0.5（4）。对[14C]腐胺运输的动力学研究表明，被动扩散导致的运输占观察到的流入量的大部分（在1 mM腐胺时为66%）。然而，存在一个小的可饱和成分，其Km值为4 - 5 mM，Vmax为30 nmol·min-1·g-1。这个Km值远高于正常成熟动物体内多胺的循环水平，因此不太可能具有生理意义。竞争研究表明，腐胺不与腺苷、精氨酸、胆碱或亮氨酸的载体相互作用。
