Carroll F Y, Finkelstein D I, Horne M K, Lawrence A J, Crawford D, Paxinos G, Beart P M
Department of Pharmacology, Monash University, Clayton, Victoria, Australia.
Neurosci Lett. 1998 Oct 16;255(2):71-4. doi: 10.1016/s0304-3940(98)00720-4.
Binding of 3H-4-methylglutamate, a novel low affinity kainate receptor agonist, was studied in brain sections of a Macaca fascicularis monkey. In cerebellar sections, 3H-4-methylglutamate bound to a single population of sites (KD = 20 nM) and was inhibited by various glutamate receptor ligands: kainate > 6-cyano-7-nitroquinoxaline-2,3-dione > L-glutamate >> AMPA. (S)-5-lodowillardiine and (RS)-2-amino-3-(3-hydroxy-5-tert-butylisoxazol-4-yl)propanoic acid (ATPA), drugs selective for the GluR5 subunit, displaced 50% and 40% of binding, respectively. Autoradiography revealed topographic binding of 3H-4-methylglutamate. Binding in cortex was highest in layer 5 and restricted to CA2/3 in hippocampus. Levels of binding were high in septum and hypothalamus. Moderate densities of binding were found in caudate-putamen, cerebellar granular layer, nucleus tractus solitarius, cuneate nucleus and area postrema. Binding in spinal cord was concentrated in dorsal horn. 3H-4-Methylglutamate shows differential binding throughout primate brain and is a valuable new ligand for low affinity kainate receptors.
在猕猴的脑切片中研究了新型低亲和力红藻氨酸受体激动剂3H-4-甲基谷氨酸的结合情况。在小脑切片中，3H-4-甲基谷氨酸与单一的位点群体结合（解离常数KD = 20 nM），并受到各种谷氨酸受体配体的抑制：红藻氨酸＞6-氰基-7-硝基喹喔啉-2,3-二酮＞L-谷氨酸＞＞α-氨基-3-羟基-5-甲基异恶唑-4-丙酸。对GluR5亚基具有选择性的药物(S)-5-碘海人藻氨酸和(RS)-2-氨基-3-(3-羟基-5-叔丁基异恶唑-4-基)丙酸（ATPA）分别取代了50%和40%的结合。放射自显影显示了3H-4-甲基谷氨酸的拓扑结合情况。在皮质中，第5层的结合最高，在海马体中局限于CA2/3区域。在隔区和下丘脑中结合水平较高。在尾状核-壳核、小脑颗粒层、孤束核、楔束核和最后区发现中等密度的结合。在脊髓中的结合集中在背角。3H-4-甲基谷氨酸在整个灵长类动物脑中表现出差异性结合，是一种用于低亲和力红藻氨酸受体的有价值的新配体。
