Studies on binding sites of GABA_A receptor complexes in brain and cultured neuronal cells

脑和培养神经元细胞中 GABA_A 受体复合物结合位点的研究

• 批准号: 04671375
• 负责人: FUKUDA Hideomi
• 金额: $ 0.96万
• 依托单位: Nihon University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for General Scientific Research (C)
• 财政年份: 1992
• 资助国家: 日本
• 起止时间: 1992 至 1993
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-04671375/
• 关键词: GABA_A receptor; Muscimol; Bicuculline; Cerebellum; ^<36>Cl^- uptake; Up-regulation; 亜急性投与; クロライドイオンチャネル; [^<35>S]TBPS結合; シナプトニューロソーム; クラライドイオンチャネル

Experiments were performed to examine nuerochemically the functional diversity of GABA_A receptors as measured by muscimol-, 5alpha-pregnane-3alpha, 21-diol-20-one (THDOC)-, and pentobarbital-stimulated ^<36>Cl^- uptake, and region-specific changes in muscimol- and THDOC-stimulated ^<36>Cl^- uptake in rats treated acutely or subacutely with a subconvulsive dose of bicuculline. The data for stimulation of ^<36>Cl^- uptake by muscimol showed a single binding site interaction in the cerebral cortex, hippocampus and cerebellum. The concentration-response curves for muscimol in the cerebral cortex and hippocampus were steep and indicated an increase of approximately 130% at the maximum concentration. In contrast, the curve for the cerebellum was shallow and exhibited a smaller maximal response (-60%. Apparent affinity for muscimol also differed among these brain regions. Although the concentration-response curves for THDOC did not fit a single-site model for the cerebral cortex and hippocam … More pus, the curve for the cerebellum was monophasic.There were no differences in the maximal stimulation induced by THDOC among the regions tested. The regional differences in ^<36>Cl^- uptake induced by pentobarbital were not as apparent as those induced by muscimol ; however, the maximal modulatory effect in the hippocampus was significantly higher than that in the cerebellum. In rats treated subacutely with a subconvulsive does of bicuculline, a significant increase in muscimol-stimulated ^<36>Cl^- uptake was observed in the cerebellum but not in the frontal cortex or hippocampus. Analysis of the concentration-response curves for muscimol-stimulated ^<36>Cl^- uptake in the cerebellum revealed that the Vmax for muscimol in the subacutely treated group was significantly higher than those for muscimol in the control and acutely treated groups without any differences in the Kd value.In addition, muscimol-stimulated ^<36>Cl^- uptake in the hippocampus of the acutely treated group was significantly higher than those in the control group. These results suggest that regional variation of ^<36>Cl^- uptake stimulated by muscimol is more apparent than those stimulated by THDOC and pentobarbital. The present results, along with our previous findings, also indicate that bicuculline up-regulation of GABA_A receptors in the cerebellum involves not only an increase in the density of the receptors as measured by binding assay, but also an increase of ^<36>Cl^- uptake mediated through GABA recognition sites. Less

实验通过神经化学方法检测GABA_A受体的功能多样性，通过蝇蕈醇、5 α-胆甾烷-3 α，21-二醇-20-酮（THDOC）和戊巴比妥刺激的大鼠对氯的摄取<36>，以及蝇蕈醇和THDOC刺激的大鼠对氯的摄取的区域特异性变化<36>，这些变化在急性或亚急性给予亚惊厥剂量的荷包牡丹碱后进行。蝇<36>蕈醇刺激^ Cl^-摄取的数据显示，在大脑皮层、海马和小脑中存在单一结合位点相互作用。蝇蕈醇在大脑皮层和海马中的浓度-反应曲线陡峭，表明在最大浓度下增加约130%。相比之下，小脑的曲线较浅，表现出较小的最大反应（约60%）。蝇蕈醇的表观亲和力在这些脑区之间也不同。虽然THDOC的浓度-反应曲线不符合大脑皮层和海马CA 1区的单位点模型， ...更多信息 脓时，小脑的刺激曲线呈双相，THDOC对小脑的最大刺激在各受试区之间无差异。戊<36>巴比妥诱导的^ Cl^-摄取的区域差异并不像蝇蕈醇诱导的那样明显;然而，海马中的最大调节效应显著高于小脑。在亚急性给予亚惊厥剂量荷包牡丹碱的大鼠中，在小脑中观察到蝇蕈醇刺激的^<36>Cl^-摄取显著增加，但在额叶皮质或海马中没有观察到。对蝇蕈醇刺激的小脑^ Cl^-摄取的浓度-反应曲线的分析<36>表明，亚急性处理组中蝇蕈醇的Vmax显著高于对照组和急性处理组中蝇蕈醇的Vmax，而Kd值无任何差异;此外，急性处理组中蝇蕈醇刺激的海马^<36>Cl^-摄取显著高于对照组。这些结果表明蝇蕈<36>醇刺激的^ Cl^-摄取的区域差异比THDOC和戊巴比妥刺激的更明显。本研究结果与我们以前的研究结果沿着也表明荷包牡丹碱上调小脑GABA_A受体不仅涉及受体密度的增加（通过结合试验测量），而且还涉及<36>通过GABA识别位点介导的^ Cl^-摄取的增加。少

项目成果

Yoshihisa Ito: "Studies on picrotoxin binding sites of GABA_A receptors in rat cortical synaptosomes" Brain Research Bulletin. 33. 373-378 (1994)

伊藤义久：“大鼠皮质突触体中 GABA_A 受体印防己毒素结合位点的研究”《大脑研究通报》。

伊藤芳久: "Characterization of diazepam insensitive 〔〓H〕Ro 15-4513 binding in rodent brain and cultured cerebellar neuronal cells" Neurochemical Research. 19. 285-295 (1994)

Yoshihisa Ito：“啮齿类动物大脑和培养的小脑神经元细胞中地西泮不敏感 [〓H]Ro 15-4513 结合的表征”《神经化学研究》19. 285-295 (1994)。

伊藤芳久: "Studies on picrotoxin binding sites of GABA_A receptors in rat cortical synaptosomes" Brain Research Bulletin. 33. 373-378 (1994)

Yoshihisa Ito：“大鼠皮质突触体中 GABA_A 受体印防己毒素结合位点的研究”《大脑研究通报》33. 373-378 (1994)。

Yoshihisa Ito, Katsuya Segawa, and Hideomi Fukuda: "Functional diversity of GABA_A receptor ligand-gated chloride channels in rat synaptoneurosomes" Synapse. (Submitted).

Yoshihisa Ito、Katsuya Sekawa 和 Hideomi Fukuda：“大鼠突触神经体中 GABA_A 受体配体门控氯离子通道的功能多样性” 突触。

伊藤芳久,瀬川勝也,福田英臣: "Functional diversity of GABA_A receptor ligand-gated chloride channels in rat synapto neurosomes" Synapse. (投稿中).

Yoshihisa Ito、Katsuya Sekawa、Hideomi Fukuda：“大鼠突触神经体中 GABA_A 受体配体门控氯离子通道的功能多样性”突触（进行中）。