Cowburn R F, Dodd P R, Hardy J A, Johnston G A
Department of Biochemistry, St. Mary's Hospital Medical School, University of London, Norfolk Place, London W2 1PG, England.
Neurochem Int. 1987;10(3):339-46. doi: 10.1016/0197-0186(87)90108-2.
Synaptosomes were prepared from frozen post mortem human brain and from fresh rat brains. These preparations were used to compare the pharmacological properties of the sodium dependent, high affinity, excitatory amino acid uptake sites in these species, using [(3)H]d-aspartate as the ligand. The kinetic parameters for the human and rat uptake sites were: K(m) = 9.14 +/- 1.34 and 6.71 +/- 0.89 ? M; and V(max) = 1.12 +/- 0.16 and 5.28 +/- 0.70 nmol/min/mg protein respectively. Both sites showed similar pharmacological profiles for the inhibition of d-aspartate uptake when a series of structural analogues were used. Detailed kinetic analyses were performed at a number of sodium concentrations to determine the sodium requirement of the uptake sites. The results in both species were consistent with a coupling ratio of one sodium ion to one d-aspartate molecule. These results demonstrate the feasibility of using synaptosomal d-aspartate uptake as a presynaptic marker of excitatory amino acid neurons in human brain.
突触体取自冷冻的人类尸检大脑和新鲜的大鼠大脑。这些制剂用于比较这些物种中依赖钠的、高亲和力的兴奋性氨基酸摄取位点的药理学特性，使用[³H]d-天冬氨酸作为配体。人类和大鼠摄取位点的动力学参数分别为：K(m)=9.14±1.34和6.71±0.89 μM；V(max)=1.12±0.16和5.28±0.70 nmol/min/mg蛋白质。当使用一系列结构类似物时，两个位点在抑制d-天冬氨酸摄取方面表现出相似的药理学特征。在多个钠浓度下进行了详细的动力学分析，以确定摄取位点对钠的需求。两个物种的结果均与一个钠离子与一个d-天冬氨酸分子的偶联比一致。这些结果证明了使用突触体d-天冬氨酸摄取作为人类大脑中兴奋性氨基酸神经元的突触前标记物的可行性。
