Activation of protein kinase C enhances NMDA-induced currents in primary cultured cerebellar granule cells: Effect of temperature and NMDA NR2 subunit composition.
Activation of protein kinase C enhances NMDA-induced currents in primary cultured cerebellar granule cells: Effect of temperature and NMDA NR2 subunit composition.
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蛋白激酶 C 的激活增强了原代培养的小脑颗粒细胞中 NMDA 诱导的电流：温度和 NMDA NR2 亚基组成的影响。
DOI：
10.1016/j.ejphar.2008.08.007
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发表时间：
2008
影响因子：
5
通讯作者：
Brotherton,BJason
中科院分区：
文献类型：
--
作者：
Popp,RLisa;Reneau,JasonC;Brotherton,BJason
采用全细胞膜片钳技术，观察100nM佛波酯(PMA)激活蛋白激酶C(PKC)对N-甲基-D-天冬氨酸(NMDA)受体功能的影响。测定原代培养的小脑颗粒细胞在体外培养过程中NMDA、NR2A和NR2B亚基组成的不同受体的表达。PMA暴露期间的温度对NMDA诱导的电流幅度以及PMA诱导的PKC异构体特异性免疫反应的移位的影响也被评估。我们观察到，无论NR2亚基的组成如何，PMA都能增强NMDA诱导的峰值电流幅度，而NMDA诱导的稳态电流幅度的增加只在13天及更老的体外小脑颗粒细胞中观察到。PMA处理不影响受体的脱敏状态(稳态与峰值电流比率)。NMDA诱导的电流幅度在PMA暴露12.5分钟时增加，这一时间与所有PMA敏感的PKC亚型免疫反应的移位相对应。与23℃PMA暴露后受体功能的增强相比，37℃PMA暴露导致NMDA诱导的电流幅度显著增强。与37℃处理相比，23℃PMA暴露后PKC免疫反应性的移位也大大减弱。虽然我们的数据支持先前的观察，即PMA激活PKC增强NMDA受体功能，但这种增强似乎不依赖于NR2亚单位的组成。此外，我们的数据强调了在生理温度下进行实验的重要性，当评估PKC对天然NMDA受体的影响时。
The purpose of this study was to determine the effect of protein kinase C (PKC) activation by 100 nM phorbol 12-myristate 13-acetate (PMA) on N-methyl-d-aspartate (NMDA) receptor function with the whole-cell patch-clamp technique. Receptors expressed in primary cultured cerebellar granule cells at days in vitro that result in different NMDA NR2A and NR2B subunit composition were assessed. The effect of temperature during PMA exposure on NMDA-induced current amplitudes as well as PMA-induced translocation of PKC isoform-specific immunoreactivity was also assessed. We observed that PMA augmented NMDA-induced peak current amplitude regardless of NR2 subunit composition and augmentation of NMDA-induced steady-state current amplitudes was only observed in 13 and older days in vitro cerebellar granule cells. PMA treatment did not affect the desensitized state (steady-state to peak current ratios) of the receptor. Augmentation of NMDA-induced current amplitude was seen by 12.5 min PMA exposure, a time that corresponded with translocation of all PMA-sensitive PKC isoform immunoreactivity. PMA exposure at 37 °C resulted in a significant enhancement of NMDA-induced current amplitude compared to augmentation of receptor function following a PMA exposure at 23 °C. Translocation of PKC immunoreactivity was also greatly attenuated at 23 °C compared to treatment at 37 °C. While our data support previous observations that activation of PKC by PMA enhances NMDA receptor function, this augmentation does not appear to be dependent upon NR2 subunit composition. Furthermore our data emphasize the importance of conducting experiments at physiological temperatures when assessing PKC effects on native NMDA receptors.