丘脑背内侧核损毁对帕金森病大鼠内侧前额叶皮层 电活动的影响.

Objective: To investigate the effect of damage to the dorsomedial nucleus of the thalamus (MD) on the electrical activity of pyramidal neurons in the medial prefrontal cortex (mPFC) of Parkinson's disease (PD) model rats, and to clarify the role of MD in the pathophysiological process of PD. Methods: The rat model of PD was established by intracerebral injection of 6-hydroxydopamine (6-OHDA) to damage the substantia nigra pars compacta (SNc), and the rats were injected with ibotenic acid (IBO) to damage MD. Twenty-four male SD rats were randomly divided into normal group, SNc damage group (PD model group), MD damage group (IBO injection in MD) and SNc+MD combined damage group (the ipsilateral MD was damaged 1 week after SNc damage), 6 in each group. Tyrosine hydroxylase immunohistochemical staining was used to observe the number of dopamine neurons in SNc and ventral tegmental area (VTA) of rats in each group, and Nissl staining was used to judge the location of electrophysiological recording points and MD damage. The firing frequency, coefficient of variation of firing interval (ISI) and firing form of pyramidal neurons in mPFC of rats in each group were observed. Results: After injection of 6-OHDA, the dopamine neurons in the damaged SNc of rats in the PD model group completely disappeared, and the number of dopamine neurons in the ipsilateral VTA decreased significantly compared with the contralateral side (P<0.01); compared with the normal group, the SNc damaged group The discharge frequency of rat mPFC pyramidal neurons was significantly increased (P<0.05), the discharge form tended to be explosive (P=0.001), and the average ISI variation coefficient increased (P<0.01); 2 weeks after MD damage, Compared with the normal group, the discharge frequency of mPFC pyramidal neurons in the SNc damage group increased significantly (P<0.01), the burst discharge increased (P<0.01), and the coefficient of variation of the average ISI increased (P<0.01); In comparison, there was no significant difference in the firing frequency of mPFC pyramidal neurons in the SNc+MD combined damage group (P>0.05), the burst discharge increased (P<0.01), and the coefficient of variation of the average ISI increased (P<0.01 ). Conclusion: MD plays an important role in regulating the activity of mPFC neurons, and the functional change of MD may be one of the important reasons for the change of mPFC neural activity in the pathophysiological process of PD. reduction [ABSTRACT FROM AUTHOR]