| Budget Amount *help |
¥1,300,000 (Direct Cost: ¥1,300,000)
Fiscal Year 2005: ¥400,000 (Direct Cost: ¥400,000)
Fiscal Year 2004: ¥900,000 (Direct Cost: ¥900,000)
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| Research Abstract |
The aim of this work was to elucidate the time-course of effects with administered acetylcholinesterase (AChE : EC3.1.1.7) in rat brain. This enzyme, known to have a trypsin-like activity, may lead to pathological changes arround the injection site tissue and introduce the accumulation of abnormal protein associated with neuronal degeneration.
A total 64 of adult male rats, deeply anesthetized with pentobarbital, were stereotaxically administered by intracerebral injection of electric eel AChE dissolved with saline at three different concentrations (1%, 5%, or 10%). After survival period of 1-84 days (1, 7, 14, 28, and 84), rats were sacrificed under the deep anesthesia by transcardial perfusion with fixative containing 4% paraformaldehyde and 0.5% grutaraldehyde in phosphate buffer (PB : pH 7.4). The brains were fixed with 4% paraformaldehyde in PB for 2days. The brain slices were cut into frozen sections and stained for AChE with sensitive histochemical method and adjacent sections for Thioflavin S (TFS), Aβ 42 with immunohistochemistry or cresyl violet. Control test were performed by BW284c51 for specific AChE inhibitor.All rats, during alive, gave any signs of changes on behaviors or figures. Specific pathological changes were not observed in any concentration of AChE or survival periods despite the surrounding area of needle hole, where some rats showed the accumulation of TFS-positive products l4days after the AChE-injection and of Aβ 42-positive immunoreactive products 28days after.
In this study, any specific pathological changes positive for AChE were observed in rat brain. However, TFS-positive products around the AChE-injected site were observed l4days after AChE injection. Aβ 42-positive products were also observed 28days after injection. These positive deposits were not appeared in other areas and may be an amyloid-like protein. We will additionally study about these products with continuous injection of AChE and with electron microscope.
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