Excitatory influence of rat subthalamic nucleus to substantia nigra pars reticulata and the pallidal complex: electrophysiological data
Excitatory influence of rat subthalamic nucleus to substantia nigra pars reticulata and the pallidal complex: electrophysiological data
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DOI：
10.1016/0006-8993(90)90952-8
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发表时间：
1990-06
期刊：
影响因子：
2.9
通讯作者：
P. Robledo;J. Féger
中科院分区：
文献类型：
--
作者：
P. Robledo;J. Féger
用γ-氨基丁酸（GABA）拮抗剂荷包牡丹碱（bicuculline）选择性化学刺激丘脑底核（STh），研究其对靶核团的投射作用。结果表明，荷包牡丹碱（0.39 mM）产生了358%的平均激活丘脑底神经元。黑质网状部（SNpr），endenduncular核（EP）和苍白球（GP）中记录的大多数细胞也被显著激活。在黑质的pars延髓（SNpc），轻微的和相反的变化产生：一半的细胞被激活，一半被抑制。在纹状体中，记录了3种类型的反应：激活、抑制和双相效应。抑制底丘脑神经元局部微量注射蝇蕈醇（0.95毫米），产生的神经元活动的细胞在SNPR，EP和GP的减少。这些结果表明，STh传达了一个重要的和永久的兴奋性影响到其靶核。在另一组实验中，为了研究STh是否利用谷氨酸在SNpr中进行神经传递，我们将谷氨酸受体拮抗剂犬尿烯酸（2.6 mM）注射到SNpr中，随后在STh中注射荷包牡丹碱。犬尿烯酸单独在非多巴胺能黑质细胞中产生30%的平均抑制，并拮抗随后荷包牡丹碱诱导的STh激活作用。这些结果进一步证实了最近的数据表明，STh的传出结构发挥兴奋作用，并提供了新的证据，丘脑底投射的神经递质传递。此外，他们强烈建议，这种激活是主要的驱动力，有助于在EP和SNpr中观察到的高水平的自发兴奋，从而平衡纹状体的主要抑制作用。
By selective chemical stimulation of the subthalamic nucleus (STh) with the γ-aminobutyric acid (GABA) antagonist bicuculline, we have studied the effect of its projections to the target nuclei. Results show that bicuculline (0.39 mM) produced a mean activation of 358% in subthalamic neurons. Most of the cells recorded in the substantia nigra pars reticulata (SNpr), the entopenduncular nucleus (EP), and the globus pallidus (GP) were also significantly activated. In the substantia nigra pars compacta (SNpc), slight and opposite changes were produced: half of the cells were activated and half were inhibited. In the striatum, 3 types of responses were recorded: activation, inhibition, and biphasic effect. Inhibition of subthalamic neurons by local microinjection of muscimol (0.95 mM), produced reductions in the neuronal activity of cells in the SNpr, the EP, and the GP. These results suggest that the STh conveys an important and permanent excitatory influence onto its target nuclei. In another set of experiments, in order to investigate whether or not the STh utilizes glutamate for neurotransmission in the SNpr, we injected the glutamate receptor antagonist kynurenic acid (2.6 mM) into the SNpr, later followed by an injection of bicuculline in the STh. Kynurenic acid alone produced a mean inhibition of 30% in non-dopaminergic nigral cells, and antagonized the subsequent bicuculline-induced activating effect of the STh. These results further confirm recent data showing that the STh exerts an excitatory action on its efferent structures, and provide new evidence for glutamatergic transmission in subthalamic projections. In addition, they strongly suggest that this activation is the principal driving force contributing to the high level of spontaneous excitation observed in the EP and the SNpr, thus balancing the main inhibitory action of the striatum.