低频电刺激脚桥核对苍白球内侧部神经元自发放电的影响

摘要

目的：通过观察低频电刺激帕金森病（PD）模型大鼠脚桥核（PPN）对苍白球内侧部（GPi）神经元放电的影响，探讨低频电刺激PPN治疗PD的作用机制。方法30只SD大鼠随机分为对照组和PD组各15只。大鼠脑右侧黑质致密部注入6-羟基多巴胺建立PD模型；采用细胞外记录方法，利用7管玻璃微电极记录观察低频电刺激、微电泳谷氨酸（Glu）及其受体阻断剂MK-801、γ-氨基丁酸（GABA）及其受体阻断剂荷包牡丹碱（BIC）对大鼠GPi神经元放电频率的影响。结果低频电刺激PPN，对照组及PD组大鼠GPi神经元反应均以抑制为主，且平均放电频率均较刺激前降低（P＜0.01）；微电泳Glu和BIC对神经元有兴奋作用，而微电泳MK-801和GABA对神经元有抑制作用。在微电泳BIC的兴奋作用的基础上低频电刺激PPN使神经元放电频率明显降低，而在微电泳MK-801抑制作用的基础上低频刺激PPN使神经元放电频率进一步降低。结论低频电刺激PPN可抑制GPi神经元活动，可能是通过调节投射到GPi神经元的Glu和GABA神经通路实现的。%Objective To explore the mechanism of the low-frequency electrical stimulate on pedunculopontine nu-cleus to treat the Parkinson (PD) through observinge the low-frequency electrical stimulation of Pedunculopontine Nucleus (PPN) in PD rat model and the effects of neurotransmitters (GPi) neurons discharge in the medial part of the globus pallidus. Methods Thirty SD rats were randomly assigned to the control group and the PD model group, with 15 in each group. PD model was established through injecting 6-OHDA into Substantia nigra compact (SNc) of black rat. Effect of low frequency electrical stimulation, micro-electrophoresis glutamate (Glu) and its receptor blocking breaking agent MK-801,γ-aminobu-tyric acid (GABA) and its receptor antagonist bicuculline (BIC) on discharge of rat neuron GPi was examined using extracel-lular unit recording methods through seven glass microelectrode recording. Results When stimulated by low frequency electrical stimulation of PPN, reactions from the control group and neuronal response GPi in PD rats were inhibited. The aver-age discharge frequency was reduced compared to pre-stimulation (P < 0.01). Micro-electrophoresis and BIC Glu excite neurons while microiontophoresis MK-801 and GABA restrain neurons. In the background of micro-electrophoresis BIC’s excitatory effects on neuron, low-frequency electrical stimulation on PPN reduced neuronal firing frequency. And in the background of inhibition effect of micro-electrophoresis MK-801, low-frequency stimulation PPN further restrain neuronal discharge frequency. Conclusion Low frequency electrical stimulation inhibits GPi PPN neuronal activity probably though regulating neurons projecting to the Glu and GABA nerve pathways in GPi neuron.