BLOOD-BRAIN BARRIER TRANSPORT OF 1-AMINOCYCLOHEXANECARBOXYLIC ACID, A NONMETABOLIZABLE AMINO-ACID FOR INVIVO STUDIES OF BRAIN TRANSPORT
BLOOD-BRAIN BARRIER TRANSPORT OF 1-AMINOCYCLOHEXANECARBOXYLIC ACID, A NONMETABOLIZABLE AMINO-ACID FOR INVIVO STUDIES OF BRAIN TRANSPORT
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DOI：
10.1111/j.1471-4159.1988.tb10596.x
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发表时间：
1988-04-01
影响因子：
4.7
通讯作者：
SMITH, QR
中科院分区：
文献类型：
--
作者：
AOYAGI, M;AGRANOFF, BW;SMITH, QR
采用原位脑灌注技术研究了戊巴比妥麻醉大鼠血脑屏障中1-氨基环己烷羧酸（ACHC）的区域转运。内流的浓度依赖关系最好地由一个具有饱和和不饱和成分的模型来描述。额叶皮层运动常数的最佳拟合值等于9.7倍。身手.mu尤其。mol/s/g为Vmax， 0.054 .mu。mol/ml为Km， 1.0倍。在没有竞争氨基酸的情况下，KD值为10-4 ml/s/g。l -苯丙氨酸或2-氨基双环[2.2.1]庚烷-2-羧酸均可使饱和内流减少85%，与脑血管中性氨基酸转运系统的转运一致。ACHC的转运Km是更常用的同系物1-氨基环戊烷羧酸的五分之一，与一些天然氨基酸（如l -蛋氨酸、l -异亮氨酸和l -酪氨酸）的转运Km相似。结果表明，乙酰胆碱酯酶可能是一种有用的探针，在体内研究氨基酸转运到脑。
Regional transport of 1-aminocyclohexanecarboxylic acid (ACHC), a nonmetabolizable amino acid, across the blood-brain barrier was studied in pentobarbital-anesthetized rats using an in situ brain perfusion technique. The concentration dependence of influx was best described by a model with a saturable and a nonsaturable component. Best-fit values for the kinetic constants of the frontal cortex equaled 9.7 .times. 10-4 .mu.mol/s/g for Vmax, 0.054 .mu.mol/ml for Km, and 1.0 .times. 10-4 ml/s/g for KD in the absence of competing amino acids. Saturable influx could be reduced by > 85% by either L-phenylalanine or 2-aminobicyclo[2.2.1]heptane-2-carboxylic acid, consistent with transport by the cerebrovascular neutral amino acid transport system. The transport Km for ACHC was one-fifth that for the more commonly used homologue, 1-aminocyclopentanecarboxylic acid, and was similar to values for several natural amino acids, such as L-methionine, L-isoleucine, and L-tyrosine. The results indicate that ACHC may be a useful probe for in vivo studies of amino acid transport into brain.