Submillisecond kinetics and low efficacy of parallel fibre Golgi cell synaptic currents in the rat cerebellum
Submillisecond kinetics and low efficacy of parallel fibre Golgi cell synaptic currents in the rat cerebellum
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DOI：
10.1111/j.1469-7793.1998.845bj.x
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发表时间：
1998-08-01
影响因子：
5.5
通讯作者：
Dieudonné, S
中科院分区：
文献类型：
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作者：
Dieudonné, S
1.采用膜片钳技术的全细胞结构，记录大鼠小脑（P12-P25）薄片上高尔基细胞的膜片钳信号。表征了它们的活性膜性质和它们从平行纤维接收的输入.大多数细胞充满了生物胞素和形态学鉴定的存在下，一个大的轴突乔木局限于颗粒层。对其中18个保存最好的细胞进行形态学参数定量分析.当高尔基体细胞的形态不能被识别时，利用高尔基体细胞轴突的特征性的慢电容电流瞬态来识别高尔基体细胞。高尔基体细胞在3 +/- 1.7 Hz下自发激发动作电位（n = 17）。它们的放电频率随去极化电流脉冲幅度的增加而线性增加，并表现出明显的适应性.当超极化的高尔基体细胞显示异常整流，这是由2 mM氯化铯阻断，表明存在的I-h样电流。高尔基体细胞接受来自平行纤维的自发兴奋性输入。该输入由小振幅（主要是单量子）EPSC组成。局部应用红藻氨酸盐对颗粒细胞的化学刺激引起具有类似性质的河豚毒素（TTX）依赖性事件。平行的纤维-高尔基体细胞EPSC同时含有AMPA和NMDA成分。NMDA成分在-60 mV下被1 mM外部镁阻断，并以31 +/- 9 ms和170 +/- 15 ms的时间常数衰减（在存在镁的情况下，在+61 mV下）。8.在存在10 μ M内部精胺的情况下，当将细胞从-70 mV去极化至+61 mV时，自发EPSC的AMPA组分显著减慢（0.96 +/-0.25 ms至1.86 +/-0.47 ms; n = 4）并且幅度降低（49 +/-7%; n = 4）。个别AMPA EPSC的衰减动力学被发现是可变的，部分原因是树枝状过滤。更详细的分析表明，突触AMPA电导在发育过程中受到调节，并且在P19-P25天比在P13-P16天关闭得更快。这些数据表明，平行的纤维高尔基体细胞输入的功效是相当低的。这对高尔基体细胞施加的抑制性反馈可以起作用的条件有很大的限制。的可能性被认为是高尔基体细胞颗粒细胞电路显示振荡行为。这一假设进行了讨论的关系到模型的阿不思和马尔。
1. The whole-cell configuration of the patch clamp technique was used to record from Golgi cells in thin slices of the rat cerebellum (P12-P25). Their active membrane properties and the input that they receive from the parallel fibres were characterized.2. Most cells were filled with biocytin and morphologically identified by the presence of a large axonal arbor restricted to the granular layer. The morphological parameters of eighteen of the best-preserved cells were quantified.3. A slow capacitive current transient, characteristic of the Golgi cell axon, was used to identify Golgi cells whenever their morphology could not be preserved.4. Golgi cells fire action potentials spontaneously at 3 +/- 1.7 Hz (n = 17). Their firing frequency increases linearly with the amplitude of depolarizing current pulses and displays marked adaptation.5. When hyperpolarized Golgi cells display an anomalous rectification which is blocked by 2 mM CsCl, indicating the presence of an I-h-like current.6. Golgi cells receive a spontaneous excitatory input from parallel fibres. This input is composed of small amplitude, mostly monoquantal, EPSCs. Chemical stimulation of granule cells by locally applied kainate evokes tetrodotoxin (TTX)-dependent events with similar properties.7. The parallel fibre-Golgi cell EPSCs have both AMPA and NMDA components. The NMDA component is blocked by 1 mM external magnesium at -60 mV and decays with time constants of 31 +/- 9 ms and 170 +/- 15 ms (at +61 mV in the presence of magnesium).8. In the presence of 10 mu M internal spermine, the AMPA component of the spontaneous EPSCs is markedly slowed (0.96 +/- 0.25 ms to 1.86 +/- 0.47 ms; n = 4) and reduced in amplitude (49 +/- 7%; n = 4) when depolarizing the cell from -70 mV to +61 mV.9. The decay kinetics of individual AMPA EPSCs were found to be variable, in part because of dendritic filtering. ii more detailed analysis reveals that the synaptic AMPA conductances are regulated during development and close faster at days P19-P25 than at days P13-P16.10. These data suggest that the efficacy of the parallel fibre-Golgi cell input is rather low. This places strong constraints on the conditions in which the inhibitory feedback exerted by the Golgi cell can be operational.11. The possibility is considered that the Golgi cell-granule cell circuit shows an oscillatory behaviour. This hypothesis is discussed in relation to the models of Albus and Marr.