6-OHDA毁损黑质致密部对大鼠PPN和VL神经元放电活动的影响

EFFECTS OF UNILATERAL LESION OF THE NIGROSTRIATAL PATHWAY BY 6-OHDA ON THE NEURONAL ACTIVITIES OF THE PEDUNCULOPONTINE NUCLEUS AND THE VENTROLATERAL THALAMIC NUCLEUS

目的:观察6-羟多巴胺单侧毁损黑质致密部多巴胺神经元后,脚桥核(PPN)和丘脑腹外侧核(VL)神经元自发放电活动的变化,探讨帕金森病(PD)的发病机制。方法:应用玻璃微电极细胞外记录法,观察对照组和PD组PPN和VL神经元的放电频率和放电形式的变化。结果:对照组和PD组大鼠PPN放电频率分别为(8.31±0.62)Hz和(10.70±0.85)Hz,PD组放电频率明显高于对照组(P<0.05)。和对照组相比,PD组PPN的不规则和爆发式放电神经元构成比例明显增多(P<0.01),同时规则放电频率增加(P<0.01)。对照组和PD组大鼠VL的放电频率分别为(6.25±0.54)Hz和(5.67±0.46)Hz,两组间没有显著性差异。VL神经元放电形式表现为不规则和爆发式放电,两组间构成比也没有明显差异,但PD组爆发式神经元放电频率明显降低(P<0.01)。结论:PD状态下,PPN神经元活动增强,PPN可能参与了PD的病理生理过程,VL神经元放电可能受PPN神经元投射的调节。

Aim： To investigate the changes in neuronal activities of the pedunculopontine nucleus （PPN） and the ventrolateral thalamic nucleus （VL） after unilateral 6-hydroxydopamin （6-OHDA） lesioning of the striatum in rats. Methods： Extracellular single-unit recordings were performed in normal rats and 6-OHDA lesioned rots to observe the firing rate and firing pattern oceuring in PPN and VL neurons. Results： The firing rate of PPN neumnes significantly increased from （8.31 ± 0.62）Hz in normal rats to （ 10.70 ±0.85）Hz in 6-OHDA lesioned rats. The firing pattern changed towards more irregular and bursty when compared with the normal rats, with the firing rate increasing in regular pattern. The firing rate of VL neurones in normal rats and 6-OHDA lesioned rats were （6.25± 0.54）Hz and （5.67± 0.46）Hz respectively, whereas there were no significant differences in these two groups. In addition, the firing pattern did not change in VL compared to normal animals. Sur- prisingly, the firing rate in burst pattern decreased significantly. Conclusion： These findings demonstrate that PPN neurons are overactive in 6-OHDAlesioned rats, indicating the participation of this nucleus in the pathophysiology of parkinsonism and the activities of VL neurons might be regulated by projection from PPN to VL.