Cardelli-Cangiano P, Cangiano C, James J H, Jeppsson B, Brenner W, Fischer J E
J Neurochem. 1981 Feb;36(2):627-32. doi: 10.1111/j.1471-4159.1981.tb01635.x.
The uptake of amino acids by microvessels isolated from brains of rats was studied. Previous studies have demonstrated alterations in blood-brain amino acid transport after portacaval shunt in rats. In order to elucidate whether such changes in the blood-brain barrier were located in the microvessels, brain microvessels were isolated from both rats with portacaval shunt and controls. Brain microvessels from rats 2 weeks after shunt operations took up significantly greater amounts of 14C-labeled neutral amino acids, but not of glutamic acid, lysine, or alpha-methylaminoisobutyric acid than microvessels from sham-operated controls. Measurement of uptake kinetics showed a higher Vmax for phenylalanine and leucine uptake and a lower Vmax for lysine uptake in microvessels from shunted rats compared with control, whereas the respective Km's of uptake were similar in both preparations. The results suggest that changes in brain microvessel transport activity account for altered brain neutral amino acid concentrations after portacaval shunt and that such changes can be studied in vitro in isolated microvessels.
研究了从大鼠脑中分离出的微血管对氨基酸的摄取情况。先前的研究表明，大鼠门腔分流术后血脑氨基酸转运发生了改变。为了阐明血脑屏障的这种变化是否位于微血管中，从门腔分流大鼠和对照组中分离出脑微血管。分流手术后2周的大鼠脑微血管摄取的14C标记中性氨基酸量明显多于假手术对照组的微血管，但对谷氨酸、赖氨酸或α-甲基氨基异丁酸的摄取量则不然。摄取动力学测量显示，与对照组相比，分流大鼠微血管中苯丙氨酸和亮氨酸摄取的Vmax较高，赖氨酸摄取的Vmax较低，而两种制剂中各自的摄取Km相似。结果表明，脑微血管转运活性的变化是门腔分流后脑中中性氨基酸浓度改变的原因，并且这种变化可以在体外分离的微血管中进行研究。
