Kyuhou Shin-ichi, Gemba Hisae
Department of Physiology, Kansai Medical University, Moriguchi, Osaka 570-8506, Japan.
Biochem Biophys Res Commun. 2007 Apr 27;356(1):187-92. doi: 10.1016/j.bbrc.2007.02.116. Epub 2007 Mar 1.
We examined electrophysiological and molecular changes of the thalamocortical system after thalamic degeneration in Purkinje cell degeneration (pcd) mice. In pcd mice, neurons in specific thalamic nuclei including the ventral medial geniculate nucleus began to degenerate around postnatal day 50, whereas the visual thalamic nucleus and nonspecific thalamic nuclei remained almost intact. In association with the morphological changes, auditory evoked potentials in the primary auditory cortex (AC) began to decrease gradually. Fast Fourier transform analysis of spontaneous cortical field potentials revealed that fast oscillation (FO) around 25 Hz occurred in the AC but not in the visual cortex. Quantitative mRNA analysis demonstrated that expression of the N-methyl-D-aspartate (NMDA) receptor was up-regulated in the AC but not in the visual cortex. Systemic administration of an NMDA antagonist abolished the FO in the AC. These results indicate that increased NMDA activity may cause the FO in the AC of pcd mice.
我们研究了浦肯野细胞变性（pcd）小鼠丘脑变性后丘脑皮质系统的电生理和分子变化。在pcd小鼠中，包括腹内侧膝状核在内的特定丘脑核中的神经元在出生后第50天左右开始变性，而视觉丘脑核和非特异性丘脑核几乎保持完整。与形态学变化相关，初级听觉皮层（AC）中的听觉诱发电位开始逐渐降低。对自发皮层场电位的快速傅里叶变换分析显示，25Hz左右的快速振荡（FO）出现在AC中，而视觉皮层中没有。定量mRNA分析表明，N-甲基-D-天冬氨酸（NMDA）受体的表达在AC中上调，但在视觉皮层中没有上调。全身给予NMDA拮抗剂可消除AC中的FO。这些结果表明，NMDA活性增加可能导致pcd小鼠AC中的FO。
