Matsuo H, Tsukada S, Nakata T, Chairoungdua A, Kim D K, Cha S H, Inatomi J, Yorifuji H, Fukuda J, Endou H, Kanai Y
Department of Pharmacology and Toxicology, Kyorin University School of Medicine, Tokyo Japan.
Neuroreport. 2000 Nov 9;11(16):3507-11. doi: 10.1097/00001756-200011090-00021.
Amino acid transport system L has been proposed to be one of the major nutrient transport systems at the blood-brain barrier. Using immunohistochemical analyses, a system L transporter LAT1 was shown to be expressed in the brain capillary endothelial cells in rats. Because LAT1 was coexpressed with 4F2 heavy chain which brings LAT1 to the plasma membrane, LAT1 is proposed to be functional in the plasma membrane of brain capillary endothelial cells. Both LAT1 and 4F2hc immunoreactivities were detected in a double line appearance surrounding endothelial cell nuclei, suggesting both proteins are present in the luminal and abluminal membranes. LAT1 is, thus, a blood-brain barrier system L transporter responsible for the permeation of aromatic or branched-chain amino acids and amino acid-related drugs such as L-DOPA.
氨基酸转运系统L被认为是血脑屏障处主要的营养物质转运系统之一。通过免疫组织化学分析，发现系统L转运体LAT1在大鼠脑毛细血管内皮细胞中表达。由于LAT1与将LAT1转运至质膜的4F2重链共表达，因此推测LAT1在脑毛细血管内皮细胞质膜中发挥功能。在内皮细胞核周围呈双线状出现LAT1和4F2hc免疫反应性，表明这两种蛋白均存在于管腔膜和管腔外膜中。因此，LAT1是一种血脑屏障系统L转运体，负责芳香族或支链氨基酸以及氨基酸相关药物（如左旋多巴）的通透。
