Effects Of Chronic Ischemia On Ultrastructure And Motor Function Of Substantia Nigra And Striatum In Rats

During the first appearance of Parkinson's disease (PD), progress of the illness developed relatively slowly. However, with the development of PD, the progress becomes more rapid. With the development of illness, more and more degeneration and necrosis of neurons in substantia nigra may contribute to this phenomenon. It was reported that the structure of capillary wall is abnormal in brain of patients with PD. Furthermore, there were reports that the respiration of patients with PD can be disturbed. These two aspects may do some effects on supplements of oxygen and blood for brain and spur degeneration in substantia nigra and striatum. There are few reports on how hypoxia and chronic ischemia influence dopamine system in substantia nigra and striatum. The objective of this research is to observe effects of chronic ischemia on ultrastructure of substantia nigra and striatum in rats; If there are some changes in ultrastructure of substantia nigra and striatum, what we want to know further is whether these kinds of changes in ultrastructure of substantia nigra and striatum have any effects on motor function; the final step of the research is to make slightly lesioning in substantia nigra or striatum by ibotenic acid or 6-OHDA and to observe whether such treatment has the same influence on motor function induced by apomorphine as chronic ischemia. Bilateral carotid artery occlusion was employed to establish animal modelfor chronic ischemia. 60 days after operation, the rats were sacrificed. The rats with bilateral carotid artery occlusion were also tested by apomorphine at different dosage. The motor function of the rats with bilateral carotid artery occlusion has been observed after treatment of apomorphine. Substantia nigra or striatum of normal rats were treated with a slight lesion. After this minimal lesion was made in substantia nigra and striatum, motor function of the rats were tested by apormorphine to clarify whether this kind of minimal lesion in substantia nigra and striatum has any effects on motor behaviors of rats.The research came to the following conclusions:1. In chronic bilateral carotid artery occlusion rats, the ultrastructure of neurons in substantia nigra and striatum was damaged. It suggest that there is a possibility that chronic-ischemia contributed to exacerbation of pathology in Parkinson's disease.2. Ultrastructure changes in substantia nigra and striatum after chronic ischemia have an effects on behavior of stereotypy and change function of dopamine system in rats.3. Minimal damage in striatum of rats can increase score of apomorphine-induced behaviors of stereotypy.4. Minimal damage in substantia nigra of rats can increase score of apomorphine-induced behaviors of stereotypy.