ELECTROPHYSIOLOGY OF GUINEA-PIG CEREBELLAR NUCLEAR-CELLS IN THE INVITRO BRAIN-STEM CEREBELLAR PREPARATION
ELECTROPHYSIOLOGY OF GUINEA-PIG CEREBELLAR NUCLEAR-CELLS IN THE INVITRO BRAIN-STEM CEREBELLAR PREPARATION
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DOI：
10.1113/jphysiol.1988.sp017288
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发表时间：
1988-10-01
影响因子：
5.5
通讯作者：
MUHLETHALER, M
中科院分区：
文献类型：
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作者：
LLINAS, R;MUHLETHALER, M
取豚鼠离体脑干-小脑标本中的小脑核神经元进行细胞内记录。这些细胞的电学性质与体外切片研究中报道的非常相似。它们的平均静息电位为-56.7.+-。1.8 mV，输入电阻为23.8.+-。M，时间常数为12.5±-。2.7毫秒。动作电位平均波幅为57.3。+-。5.28 mV(n=20)。除了产生快速动作电位所需的离子机制外，小脑核神经元还表现出低阈值的钙依赖峰，在阳极断裂后产生强大的反弹兴奋。这种类型的电响应性在切片制备中是不存在的。与Purkinje细胞中所描述的相似，存在非失活的Na+电导可进一步增强阳极断裂反应。电刺激小脑皮质或白质后，可在小脑核神经元记录到兴奋性和抑制性突触电位(EPSP-IPSP序列)。直接兴奋苔藓或攀缘纤维传入的侧支可诱发EPSPS。IPSP可直接或顺行激活浦肯野细胞。通过给药骆驼蓬碱在小脑核神经元中产生强大的EPSP-IPSP序列或纯IPSP序列来测试橄榄-小脑系统的完整性。这些IPSP之后往往伴随着细胞的反弹放电。这些结果表明，橄榄-小脑通路除了激活小脑皮质外，还对小脑核细胞施加一系列强大而复杂的突触事件。因此，它是一个真正的传入系统，在小脑生理学中具有独特的作用。
Intracellular recordings were obtained from cerebellar nuclear neurones in the isolated brain stem-cerebellar preparation of guinea-pigs in vitro. The electrical properties of the cells were quite similar to those reported in in vitro slice studies. They have an average resting potential of -56.7 .+-. 1.8 mV, an input resistance of 23.8 .+-. 4.9 M.OMEGA., and a time constant of 12.5 .+-. 2.7 ms. The action potentials had an average amplitude of 57.3 .+-. 5.28 mV (n = 20). In addition to the ionic mechanisms required for the generation of the fast action potential, cerebellar nuclear neurones displayed a low-threshold Ca2+-dependent spike which produced a powerful rebound excitation following anodal break. This type of electroresponsiveness was absent in the slice preparation. The anodal break response was further enhanced by the presence of a non-inactivating Na+ conductance similar to that described in Purkinje cells. Following electrical stimulation of the cerebellar cortex or the underlying white matter, excitatory and inhibitory synaptic potentials (EPSP-IPSP sequences) could be recorded in cerebellar nuclear neurones. The EPSPs were elicited by direct activation of collaterals of mossy or climbing fibre afferents. The IPSPs follwed direct or orthodromic Purkinje cell activation. The integrity of the olivo-cerebellar system was tested by the administration of harmaline which produced powerful EPSP-IPSP sequences or pure IPSPs in cerebellar nuclear neurones. These IPSPs were often followed by a rebound firing of the cells. These results indicate that the olivo-cerebellar pathway, in addition to its activation of the cerebellar cortex, exerts a powerful and complex set of synaptic events on cerebellar nuclear cells. As such it is a true afferent system, having a distinct role in cerebellar physiology.