Quisqualate-stimulated phosphatidylinositol breakdown in rat cerebellar membranes.
Quisqualate-stimulated phosphatidylinositol breakdown in rat cerebellar membranes.
复制标题
君子草酸刺激大鼠小脑膜中的磷脂酰肌醇分解。
DOI：
10.1111/j.1471-4159.1992.tb09776.x
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发表时间：
1992
影响因子：
4.7
通讯作者：
Fain,JN
中科院分区：
文献类型：
--
作者：
Llahi,S;Claro,E;Fain,JN
研究了一种兴奋性氨基酸激动剂——半品质酸（quisqualate）对外源添加的磷脂酰肌醇分解的影响。在鸟苷5′‐O‐（3‐硫代三磷酸）（gtp - γ s）存在的情况下，半品质酸以剂量依赖的方式刺激磷脂酶C的活性。半最大激活的准质量反应需要0.15 γMGTPγS，在300 nM的游离Ca2+浓度下是最佳的。使用外源性磷脂酰肌醇4,5 -二磷酸或内源性标记的磷酸肌醇作为小脑膜磷脂酶C的底物，也可以刺激磷酸肌醇分解。在鸟嘌呤核苷酸存在的情况下，其他兴奋性氨基酸激动剂，如l -谷氨酸、反式- d、1 - 1 -氨基环-戊基- 1,3 -二羧酸和ibotenate，但不是n -甲基- d -天冬氨酸，会刺激磷脂酰肌醇分解。然而，在这些兴奋性氨基酸激动剂中，quisqualate表现出最高的反应。这些数据表明，兴奋性氨基酸通过依赖于鸟嘌呤核苷酸存在的过程直接激活磷酸肌肽特异性磷脂酶C。
The effect of quisqualate, an excitatory amino acid agonist, on the breakdown of exogenously added phosphatidylinositol was investigated in a membrane preparation from the cerebellum of young rats. Quisqualate stimulated phospholipase C activity in a dose‐dependent manner in the presence of guanosine 5′‐O‐(3‐thiotriphosphate) (GTPγS). Half‐maximal activation of the quisqualate response required 0.15 γMGTPγS and was optimal at a free Ca2+concentration of 300 nM.Phosphoinositide breakdown was also stimulated by quisqualate using either exogenous phosphatidylinositol 4,5‐bisphosphate or endogenous labeled phosphoinositides as the substrate for phospholipase C in cerebellar membranes. In the presence of guanine nucleotides, other excitatory amino acid agonists, such asl‐glutamate,trans‐d,l‐1‐aminocyclo‐pentyl‐1,3‐dicarboxylic acid, and ibotenate, but notN‐methyl‐d‐aspartate, stimulated phosphatidylinositol breakdown. However, quisqualate displayed the highest response among these excitatory amino acid agonists. These data indicate that there is a direct activation of phosphoinositide‐specific phospholipase C by excitatory amino acids through a process dependent on the presence of guanine nucleotides.