Department of Physiology and Pathophysiology, School of Medicine, Xi'an Jiaotong University, Yan Ta Xi Lu 76, Xi'an, China.
Brain Res. 2010 Apr 9;1324:54-63. doi: 10.1016/j.brainres.2010.02.008. Epub 2010 Feb 10.
The substantia nigra pars reticulata (SNr) plays a key role in the pathophysiology of Parkinson's disease (PD). It has been well documented that the SNr is not a homogeneous structure, and the lateral and medial subregions of the SNr receive different projections from the sensorimotor and limbic striatum, respectively. However, specific changes in firing activity of SNr subregions in PD remain unclear. In the present study, the spontaneous firing activity of GABAergic neurons in the lateral and medial SNr of rats with unilateral 6-hydroxydopamine lesions of the substantia nigra pars compacta (SNc) or medial forebrain bundle (MFB) has been examined. Extracellular recordings indicated that the firing rate of lateral SNr neurons increased significantly and firing pattern of these neurons changed towards more irregular and bursty after SNc or MFB lesions compared to normal rats. In contrast, the firing rate and pattern of medial SNr neurons in rats with SNc lesions were unaltered when compared with that of normal rats. However, MFB lesions in rats decreased the firing rate of medial SNr neurons and firing pattern of these neurons changed towards more bursty. In addition, SNc lesions in rats increased the firing rate of the neurons with regular and irregular firing patterns within lateral but not in medial SNr, while the firing rate of the neurons within lateral and medial SNr with each firing pattern was not altered after MFB lesions. These results suggest that GABAergic neurons of SNr subregions have differential change of firing activity in the pathophysiology of PD.
黑质网状部（SNr）在帕金森病（PD）的病理生理学中起着关键作用。已有充分的文献记载，SNr 不是一个均质结构，其外侧和内侧亚区分别接收来自感觉运动和边缘纹状体的不同投射。然而，PD 中 SNr 亚区放电活动的具体变化仍不清楚。在本研究中，单侧 6-羟多巴胺损毁黑质致密部（SNc）或中脑边缘束（MFB）后的大鼠 SNr 外侧和内侧 GABA 能神经元的自发性放电活动被检测到。细胞外记录表明，与正常大鼠相比，SNc 或 MFB 损伤后，外侧 SNr 神经元的放电率显著增加，放电模式向更不规则和爆发性转变。相比之下，SNc 损伤后，内侧 SNr 神经元的放电率和模式与正常大鼠相比没有变化。然而，MFB 损伤降低了内侧 SNr 神经元的放电率，使这些神经元的放电模式向更爆发性转变。此外，SNc 损伤增加了外侧 SNr 中具有规则和不规则放电模式的神经元的放电率，但 MFB 损伤后，每种放电模式的外侧和内侧 SNr 神经元的放电率都没有改变。这些结果表明，SNr 亚区的 GABA 能神经元在 PD 的病理生理学中有不同的放电活动变化。
