Primary afferent synaptic responses recorded from trigeminal caudal neurons in a mandibular nerve—brainstem preparation of neonatal rats
Primary afferent synaptic responses recorded from trigeminal caudal neurons in a mandibular nerve—brainstem preparation of neonatal rats
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下颌神经三叉神经尾部神经元记录的初级传入突触反应——新生大鼠脑干准备
DOI：
10.1111/j.1469-7793.2000.00503.x
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发表时间：
2000
期刊：
影响因子：
--
通讯作者：
Tomoyuki Takahashi
中科院分区：
文献类型：
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作者：
K. Onodera;M. Hamba;Tomoyuki Takahashi
1从附着下颌神经的新生大鼠脑干旁切片中视觉识别的三叉神经尾侧核浅层（胶状质）中的神经元进行全细胞膜片钳记录。2以0.03Hz频率刺激下颌神经，可在三叉神经尾侧神经元上诱发复合兴奋性突触后电位（EPSP）或电流（EPSC）。当以较高频率（> 0.5Hz）刺激时，复合突触反应大部分减弱，并且保留小部分。该成分具有单突触性质，在高频刺激（33 - 50 Hz）后具有稳定的突触潜伏期。3 N-甲基-D-天冬氨酸（NMDA）受体拮抗剂D（-）-2-氨基-5-膦酰基戊酸（D-AP 5，50 μM）显著减弱慢多突触EPSC。AMPA/红藻氨酸受体拮抗剂6-氰基-7-硝基喹喔啉-2，3-二酮（CNQX，10 μM）极大地减弱了单突触EPSC，但仅微弱地减弱了慢多突触EPSC。同时应用CNQX和D-AP 5完全消除了EPSC。通过重复刺激分离的单突触EPSC具有NMDA和非NMDA组分。4高阈值的单突触EPSC潜伏期较长。在重复刺激（0.5 ~ 5.0Hz）时，高阈值、长潜伏期的EPSC以活动依赖性方式逐步增强。这些EPSC的估计传导速度落入C纤维范围内。观察到非NMDA和NMDA EPSC的活性依赖性增强，并伴有EPSC振幅变异系数的显著降低。5我们认为EPSC的活动依赖性增强是在突触前诱导的，它可能是初级传入C纤维活动依赖性过度兴奋的基础。
1 Whole‐cell patch‐clamp recordings were made from the neurons in the superficial trigeminal caudal nucleus (substantia gelatinosa) visually identified in a parasagittal brainstem slice of neonatal rat with the mandibular nerve attached. 2 Stimulation of the mandibular nerve at 0·03 Hz evoked compound excitatory postsynaptic potentials (EPSPs) or currents (EPSCs) in trigeminal caudal neurons. When stimulated at higher frequency (> 0·5 Hz), compound synaptic responses were largely attenuated and a small component remained. This component had a monosynaptic nature, following high‐frequency stimulation (33‐50 Hz) with a stable synaptic latency. 3 The N‐methyl‐D‐aspartate (NMDA) receptor antagonist D(‐)‐2‐amino‐5‐phosphonopentanoic acid (D‐AP5, 50 μM) largely attenuated the slow polysynaptic EPSCs. The AMPA/kainate receptor antagonist 6‐cyano‐7‐nitroquinoxaline‐2,3‐dione (CNQX, 10 μM) largely attenuated monosynaptic EPSCs, but only weakly attenuated slow polysynaptic EPSCs. Simultaneous application of CNQX and D‐AP5 completely abolished EPSCs. The monosynaptic EPSCs isolated by repetitive stimulation had both NMDA and non‐NMDA components. 4 Monosynaptic EPSCs having high threshold had a relatively long latency. During repetitive stimulation (0·5‐5·0 Hz), EPSCs having high threshold and long latency underwent a stepwise potentiation in an activity‐dependent manner. The conduction velocity estimated for these EPSCs fell into the range of C‐fibres. The activity‐dependent potentiation was observed for both non‐NMDA and NMDA EPSCs and was accompanied by a significant decrease in the coefficient of variation of EPSC amplitude. 5 We suggest that the activity‐dependent potentiation of EPSCs is induced presynaptically and that it may underlie the wind‐up phenomenon, an activity‐dependent hyperexcitability of the primary afferent C‐fibres.