N-methyl-D-aspartate/glycine and quisqualate/kainate receptors expressed in Xenopus oocytes: antagonist pharmacology.
N-methyl-D-aspartate/glycine and quisqualate/kainate receptors expressed in Xenopus oocytes: antagonist pharmacology.
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发表时间：
1989-03
影响因子：
3.6
通讯作者：
T. Verdoorn;N. W. Kleckner;R. Dingledine
中科院分区：
文献类型：
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作者：
T. Verdoorn;N. W. Kleckner;R. Dingledine
通过定量药理学研究，测定了大鼠脑mRNA注射后爪蟾卵母细胞中表达的兴奋性氨基酸受体的性质。在注射mrna的卵母细胞中观察到具有n -甲基- d -天冬氨酸（NMDA）和准质酸/盐酸盐受体特性的平滑电流。NMDA诱导电流的Schild分析表明，EAA受体拮抗剂d -2-氨基-5-磷酸戊酸酯（D-APV）对卵母细胞NMDA受体具有竞争性阻断作用，因为Schild回归是线性的，斜率在100微米D-APV范围内与单位（1.03 +/- 0.025）无显著差异。D-APV对立的回目估计NMDA电流(5.87 + / - 0.043)几乎相同,D-APV作为L-aspartate拮抗剂(pA2 = 5.86 + / - 0.073,斜率= 0.97 + / - 0.036),表明这两个受体激动剂选择性NMDA受体卵母细胞的浓度远高于1毫米,6-Nitro-7-cyano-quinoxaline-2 3-dione (CNQX)降低了最大门冬氨酸反应明显减少(70% 15 microM CNQX)但NMDA EC50没有影响。CNQX对NMDA受体上的甘氨酸位点施加混合竞争性-非竞争性阻滞；15 μ m CNQX使甘氨酸EC50提高了5倍，最大甘氨酸反应降低了35%。此外，CNQX对盐酸盐引起的电流具有强大的竞争性拮抗作用。柴尔德回归在30微米CNQX范围内呈线性，斜率为1.02 +/- 0.014，pA2为6.53 +/- 0.029。2微米CNQX对kainate或NMDA电流的阻断不依赖于电压。D-APV对盐酸盐诱发电流的拮抗作用较弱，pA2为3.39 +/- 0.044，但Schild回归斜率略小于1（0.90 +/- 0.03）。这些数据证明了介导盐酸盐和NMDA诱导电流的受体之间存在明显的药理学差异，并量化了CNQX和D-APV作用于NMDA/甘氨酸和准盐酸盐/盐酸盐受体的效力。讨论了这些数据对卵母细胞EAA受体鉴定和神经元EAA受体分类的意义。
Quantitative pharmacological studies were done to determine the properties of excitatory amino acid receptors expressed in Xenopus oocytes injected with rat brain mRNA. Smooth currents with properties indicative of N-methyl-D-aspartate (NMDA) and quisqualate/kainate receptors were observed in mRNA-injected oocytes. Schild analysis of currents evoked by NMDA indicated that the EAA receptor antagonist D-2-amino-5-phosphonovalerate (D-APV) exerted a competitive block of the oocyte NMDA receptor, because the Schild regression was linear with a slope not significantly different from unity (1.03 +/- 0.025) up to 100 microM D-APV. The pA2 estimated for D-APV antagonism of NMDA currents (5.87 +/- 0.043) was nearly identical to that for D-APV as an L-aspartate antagonist (pA2 = 5.86 +/- 0.073, slope = 0.97 +/- 0.036), suggesting that these two agonists are selective for NMDA receptors in oocytes up to concentrations well above 1 mM. 6-Nitro-7-cyano-quinoxaline-2,3-dione (CNQX) reduced the maximum NMDA response significantly (70% reduction by 15 microM CNQX) but had no effect on the NMDA EC50. CNQX exerted a mixed competitive-noncompetitive block of the glycine site on NMDA receptors; 15 microM CNQX increased the glycine EC50 by 5-fold and reduced the maximum glycine response by 35%. In addition, CNQX exerted a potent and competitive antagonism of currents evoked by kainate. The Schild regression was linear up to 30 microM CNQX with a slope of 1.02 +/- 0.014 and a pA2 of 6.53 +/- 0.029. The block of kainate or NMDA currents by 2 microM CNQX was not voltage dependent. D-APV exerted a weak antagonism of kainate-evoked currents, with a pA2 of 3.39 +/- 0.044, but the slope of the Schild regression was slightly less than 1 (0.90 +/- 0.03). These data demonstrate a clear pharmacological distinction between receptors that mediate the kainate- and NMDA-induced currents and quantify the potency of CNQX and D-APV acting at NMDA/glycine and quisqualate/kainate receptors. The implications of these data for the identification of EAA receptors in oocytes and the classification of neuronal EAA receptors are discussed.