SYNAPTIC CURRENTS IN CEREBELLAR PURKINJE-CELLS
SYNAPTIC CURRENTS IN CEREBELLAR PURKINJE-CELLS
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DOI：
10.1073/pnas.87.7.2662
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发表时间：
1990-04-01
影响因子：
11.1
通讯作者：
ARMSTRONG, CM
中科院分区：
文献类型：
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作者：
KONNERTH, A;LLANO, I;ARMSTRONG, CM
众所周知，小脑浦肯野细胞接受来自小脑外部两条主要通路的强烈兴奋性输入和来自小脑皮质两种类型神经元的抑制性输入。这些通路的功能和突触强度仅部分为人所知。我们将膜片钳技术应用于大鼠小脑薄片中的浦肯野细胞，直接测量了来自两条主要兴奋通路和一条抑制性输入的突触后电流。抑制性联会电流是自发产生的，频率很高，幅度变化很大，在我们的记录条件下，内部氯离子含量很高，从小于100pA到大于1nA。这些电流被α-氨基丁酸酯A型拮抗剂荷包牡丹碱阻断。其中一个兴奋性输入为ALL或NONE。对于阈值刺激，当突触前纤维被成功刺激时，突触电流要么是全幅的，要么完全不存在。这种突触电流通常大于1nA，实际上可以被2微米6-氰基-7-硝基喹恶啉-2，3-二酮消除，这是一种被认为是对非N-甲基-D-天冬氨酸类型的谷氨酸受体具有特异性的阻断剂。它要么全有要么全无的特征表明它是由攀升纤维突触产生的。另一种兴奋性输入产生的突触电流随着刺激强度的变化而平稳地分级。我们认为这种反应源于苔藓纤维或颗粒细胞的刺激。与这一输入有关的突触电流也可被2微米6-氰基-7-硝基喹恶啉-2，3-二酮基本消除。
Cerebellar Purkinje cells are known to receive strong excitatory input from two major pathways originating outside the cerebellum and inhibitory input from two types of neurons in the cerebellar cortex. The functions and synaptic strengths of these pathways are only partially known. We have used the patch-clamp technique applied to Purkinje cells in thin slices of rat cerebellum to measure directly the postsynaptic currents arising from the two major excitatory pathways and one of the inhibitory inputs. Inhibitory synpatic currents occur spontaneously with high frequency and are variable in amplitude, ranging, in our recording conditions with high internal Cl-, from less than 100 pA to more than 1 nA. These currents are blocked by the .gamma.-aminobutyrate type A antagonist bicuculline. One of the excitatory inputs is all or none. For threshold stimulation, the synaptic current is either full amplitude, when the presynaptic fiber is successfully stimulated, or completely absent. This synaptic current is often larger than 1 nA and is virtually eliminated by 2 .mu.M 6-cyano-7-nitroquinoxaline-2,3-dione, a blocking agent thought to be specific for glutamate receptors that are not of the N-methyl-D-aspartate type. Its all-or-none character identifies it as arising from a climbing-fiber synapse. The other excitatory input produces a synaptic current that is smoothly graded as a function of stimulus intensity. This response we believe arises from the stimulation of mossy fibers or granule cells. The synaptic current associated with this input is also largely eliminated by 2 .mu.M 6-cyano-7-nitroquinoxaline-2,3-dione.