Pharmacological characterization of metabotropic glutamate receptors coupled to phospholipase D in the rat hippocampus
Pharmacological characterization of metabotropic glutamate receptors coupled to phospholipase D in the rat hippocampus
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DOI：
10.1111/j.1476-5381.1996.tb15503.x
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发表时间：
1996-06
影响因子：
7.3
通讯作者：
D. Pellegrini-Giampietro;Serenella Albani Torregrossa;F. Moroni
中科院分区：
文献类型：
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作者：
D. Pellegrini-Giampietro;Serenella Albani Torregrossa;F. Moroni
磷脂酶D（Phospholipase D，PLD）是磷脂酸和甘油二酯形成的信号转导途径中的关键酶。为了确定PLD偶联的代谢型谷氨酸受体（mGluR）的药理学特征，在存在mGluR激动剂或拮抗剂的情况下，在成年大鼠脑切片中测量PLD活性。还检查了相同试剂对磷脂酶C（PLC）途径的激活。2 mGluR选择性激动剂（1 S，3R）-1-氨基环戊烷-1，3-二羧酸[（1 S，3R）-ACPD]诱导海马、新皮质和纹状体中PLD的浓度依赖性（10-300 μm）激活，但在小脑中不诱导。这种效应在海马切片中特别明显，因此用于所有后续实验。3.不同激动剂对PLD反应的作用大小顺序为：使君子酸>鹅膏蕈氨酸>（2S，3S，4S）-α-（羧基环丙基）-甘氨酸>（1 S，3R）-ACPD > L-半胱氨酸亚磺酸> L-天冬氨酸> L-谷氨酸。L-（+）-2-氨基-4-膦酰基丁酸和离子型谷氨酸受体激动剂N-甲基-D-天冬氨酸、α-氨基-3-羟基-5-甲基-4-异恶唑丙酸和红藻氨酸不能激活PLD。(RS)第一组mGluRs的激动剂3，5-二羟基苯甘氨酸（100-300 μm）刺激PLC，但抑制100 μm（1 S，3R）-ACPD引起的PLD反应。第一组和第二组mGluRs的竞争性拮抗剂4（+）-α-甲基-4-羧基苯甘氨酸（0.1 - 1 mM）引起显著的PLD反应。第一组mGluRs的拮抗剂L-（+）-2-氨基-3-膦酰基丙酸（1 mM）抑制100 μm（1 S，3R）-ACPD-诱导的PLC反应，但产生强烈的PLD刺激。5 12-O-十四酰基佛波醇13-乙酸和佛波醇12，13-二丁酸酯（PDBu），蛋白激酶C的激活剂，在1 μm时对与PLD相关的mGluR具有刺激作用，但抑制（1 S，3R）-ACPD-诱导的磷酸肌醇水解。蛋白激酶C抑制剂staurosporine（1和10 μm）可降低1 μm PDBu诱导的PLD激活，但不降低100 μm（1 S，3R）-ACPD诱导的PLD激活。6我们的研究结果表明，大鼠海马中PLD连接的mGluR可能不同于任何已知的与PLC或腺苷酸环化酶偶联的mGluR亚型。此外，它们表明存在与PLC和PLD途径偶联的独立mGluR，并且mGluR激动剂可以通过PKC非依赖性机制刺激PLD。
1 Phospholipase D (PLD) is the key enzyme in a signal transduction pathway leading to the formation of the second messengers phosphatidic acid and diacylglycerol. In order to define the pharmacological profile of PLD‐coupled metabotropic glutamate receptors (mGluRs), PLD activity was measured in slices of adult rat brain in the presence of mGluR agonists or antagonists. Activation of the phospholipase C (PLC) pathway by the same agents was also examined. 2 The mGluR‐selective agonist (1S, 3R)‐1‐aminocyclopentane‐1, 3‐dicarboxylic acid [(1S, 3R)‐ACPD] induced a concentration‐dependent (10–300 μm) activation of PLD in the hippocampus, neocortex, and striatum, but not in the cerebellum. The effect was particularly evident in hippocampal slices, which were thus used for all subsequent experiments. 3 The rank order of potencies for agonists stimulating the PLD response was: quisqualate > ibotenate > (2S, 3S, 4S)‐α‐(carboxycyclopropyl)‐glycine > (1S, 3R)‐ACPD > L‐cysteine sulphinic acid > L‐aspartate > L‐glutamate. L‐(+)‐2‐Amino‐4‐phosphonobutyric acid and the ionotropic glutamate receptor agonists N‐methyl‐D‐aspartate, α‐amino‐3‐hydroxy‐5‐methyl‐4‐isoxazolepropionic acid, and kainate failed to activate PLD. (RS)‐3, 5‐dihydroxyphenylglycine (100–300 μm), an agonist of mGluRs of the first group, stimulated PLC but inhibited the PLD response elicited by 100 μm (1S, 3R)‐ACPD. 4 (+)‐α‐Methyl‐4‐carboxyphenylglycine (0.1‐1 mM), a competitive antagonist of mGluRs of the first and second group, elicited a significant PLD response. L‐(+)‐2‐Amino‐3‐phosphonopropionic acid (1 mM), an antagonist of mGluRs of the first group, inhibited the 100 μm (1S, 3R)‐ACPD‐induced PLC response but produced a robust stimulation of PLD. 5 12‐O‐Tetradecanoylphorbol 13‐acetic acid and phorbol 12, 13‐dibutyrate (PDBu), activators of protein kinase C, at 1 μm had a stimulatory effect on mGluRs linked to PLD but depressed (1S, 3R)‐ACPD‐induced phosphoinositide hydrolysis. The protein kinase C inhibitor, staurosporine (1 and 10 μm) reduced PLD activation induced by 1 μm PDBu but not by 100 μm (1S, 3R)‐ACPD. 6 Our results suggest that PLD‐linked mGluRs in rat hippocampus may be distinct from any known mGluR subtype coupled to PLC or adenylyl cyclase. Moreover, they indicate that independent mGluRs coupled to the PLC and PLD pathways exist and that mGluR agonists can stimulate PLD through a PKC‐independent mechanism.