Baltrons M A, García A
Instituto de Biología Fundamental V. Villar Palasi and Departamento de Bioquímica y Biología Molecular, Universidad Autónoma de Barcelona, Bellaterra, Spain.
Eur J Neurosci. 1997 Nov;9(11):2497-501. doi: 10.1111/j.1460-9568.1997.tb01667.x.
In cultured rat cerebellar astroglia kainate induces cGMP formation with low potency (EC50 310 microM). In the presence of cyclothiazide, a blocker of alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionate (AMPA) receptor desensitization, the effect of kainate was potentiated and glutamate and AMPA elicited large increases (> 100-fold) in cGMP levels. The response to all three agonists was abolished by the nitric oxide synthase inhibitor N(G)-nitro-L-arginine and required extracellular calcium. Uptake of Co2+ was induced by AMPA in a limited population of astroglial cells and this effect was potentiated by cyclothiazide. These results indicate that calcium-permeable AMPA receptors mediate stimulation of nitric oxide formation in cerebellar astroglia. This effect may be relevant for glutamate-dependent synaptic plasticity processes in the cerebellum.
在培养的大鼠小脑星形胶质细胞中，海藻酸盐以低效能诱导环鸟苷酸（cGMP）形成（半数有效浓度[EC50]为310微摩尔）。在存在环噻嗪（一种α-氨基-3-羟基-5-甲基-4-异恶唑丙酸[AMPA]受体脱敏阻滞剂）的情况下，海藻酸盐的作用增强，谷氨酸和AMPA引起cGMP水平大幅升高（超过100倍）。一氧化氮合酶抑制剂N（G）-硝基-L-精氨酸消除了对所有三种激动剂的反应，且该反应需要细胞外钙。在有限数量的星形胶质细胞中，AMPA诱导钴离子（Co2+）摄取，环噻嗪可增强此效应。这些结果表明，钙通透性AMPA受体介导小脑星形胶质细胞中一氧化氮形成的刺激。这种效应可能与小脑中谷氨酸依赖性突触可塑性过程相关。
