Fiedler J L, Inestrosa N C, Bustos G
J Neurosci Res. 1986;16(3):505-15. doi: 10.1002/jnr.490160306.
The specific binding of L-[3H]-glutamic acid (GLU) was examined in membrane preparations derived from heads of Drosophila melanogaster. L-[3H]-GLU bound to the membrane preparation with biphasic kinetics in a reversible and saturable way. The specific binding was inhibited by Cl- and Ca2+ ions. Saturation analysis of the data fit a model of two independent binding sites with dissociation constants (KD) of 29 nM and 249 nM and corresponding binding site densities (Bmax) of 5.7 and 24.6 pmol/mg protein. A series of excitatory amino acid receptor agonists and antagonists were tested as inhibitors of L-[3H]-GLU specific binding. Some compounds almost totally abolished the specific binding, whereas others reduced the binding to 45% over the concentration range used. Among the first type of inhibitors, L-GLU was the most potent, D-aspartate (D-ASP) and D-GLU were 10 times less effective than L-GLU, whereas quisqualic acid had the lowest potency. Among the second type of inhibitors, glutamate diethyl ester, D-alpha-amino adipate, and N-methyl-D-aspartate showed the highest potency, and DL-2-amino-4-phosphonobutyrate was the less effective. Kainic acid and gamma-amino butyric acid were not able to modify at any concentration used the specific binding of L-[3H]-GLU. These data suggest the presence of putative GLU receptors in the brain of Drosophila.
在源自黑腹果蝇头部的膜制剂中检测了L-[3H]-谷氨酸（GLU）的特异性结合。L-[3H]-GLU以双相动力学、可逆且可饱和的方式与膜制剂结合。特异性结合受到Cl-和Ca2+离子的抑制。数据的饱和分析符合两个独立结合位点的模型，解离常数（KD）分别为29 nM和249 nM，相应的结合位点密度（Bmax）分别为5.7和24.6 pmol/mg蛋白质。测试了一系列兴奋性氨基酸受体激动剂和拮抗剂作为L-[3H]-GLU特异性结合的抑制剂。一些化合物几乎完全消除了特异性结合，而其他化合物在所用浓度范围内将结合降低至45%。在第一类抑制剂中，L-GLU最有效，D-天冬氨酸（D-ASP）和D-GLU的效力比L-GLU低10倍，而喹啉酸的效力最低。在第二类抑制剂中，谷氨酸二乙酯、D-α-氨基己二酸和N-甲基-D-天冬氨酸显示出最高的效力，而DL-2-氨基-4-膦酰丁酸的效力较低。 kainic酸和γ-氨基丁酸在任何所用浓度下都不能改变L-[3H]-GLU的特异性结合。这些数据表明黑腹果蝇大脑中存在假定的GLU受体。
