Analysis Of The Firing Patterns In The Globus Pallidus Of Parkinson's Disease Model Rats

Parkinson's disease (PD) is a common neurodegenerative disorder in clinic, which associated with a series of motor functional impairment like tremor, rigidity, dystonia and bradykinesia. It is characterized by a selective loss of dopaminergic(DAG) neurons in the substantia nigra and result in a decrease of dopamine (DA) in the substantia nigra to striatum path. The recent researches show that the abnormal electric activities in the basal ganglia. Early clinic electrophysiological researches showed that the frequency of the firing increased in the basal ganglia especially in the globus pallidus internal(GPi) which leaded the symptoms of PD. 1-Methyl-4-Phenyl-1,2,3,6-Tetrahydropyridine(MPTP) animals studies indicated that symptoms like dystonia and bradykinesia might be related with abnormal firing in the globus pallidus (GP) neurons. So recording and analysis the information counted in the electric activities of GP neurons was important to release the change of PD firing pattern in the basal ganglia. And it was also important to release the affect of the basal ganglia and the pathological and physiological process of PD. Using 6-hydroxydopamine (6-OHDA) which could kill the DAG neurons in the substantia nigra to striatum path to construct the hemiparkinsonism rat model was one of the most useful methods to make the PD model. The study used 6-OHDA to construct PD rat model with Spraque-Donw(SD)rats, recorded the spontaneous firing of GP neurons pathologically and physiologically and studied the change of firing pattern. During the study, ROTA - ROD test, immunohistochemical test, immunofluorescent test and GP neuron firing record were used to test the PD rats'ethological appearance, TH-ir DAG neurons in the substantia nigra and the change of firing pattern in the GP. The results showed that the PD rats'ability of keeping balance on the accelerated roller were lower than the control rats (P<0.05). The immunohistochemical and immunofluorescent test showed that the number of the PD rats'TH-ir neuron was lower in the 6-OHDA injection side than in the non-injection side (P<0.01). The electrophysiological recording showed the frequency of the PD rats'firing (21.10±3.21Hz) was high than the control rats (6.04±2.12Hz) (P<0.01). Four types of firing were recorded in the control rats and three types were recorded in the PD model rats. Burst firing rate was 59% at 4 weeks post-lesion and 61% at 8 weeks post-lesion in PD model rats, and both 11% in control rats (P<0.01). There was a close-set under 100ms in the return map of interspike inter (ISI). The showed that the physiological data was to centralize than the pathological data. The study showed that there was a great change in the firing pattern of PD rats'GP neurons and also it showed some nonlinear characteristics. It is helpful to diagnosis and treat PD.