Changes in monoamine oxidase activity during thrombotic cerebral ischemia and protection mechanisms of ginkgolide B in tree shrews

AIM:The present study was designed to examine changes in monoamine oxidase (MAO) activity during cerebral ischemia and whether ginkgolide B's brain protection challenges with inhibiting monoamine oxidase. METHODS: The focal thrombotic cerebral ischemia was formed by photochemistry-induced in tree shews.MAO activities in different areas which include ischemic,core, penumbra and contralater and serum, were tested by enzyme color-compared way. The protein contents in different area above was examined by amino acid autoanalytic apparatus. RESULTS:MAO activities in ischemic core in different group were much lower than that in the sham operation group and contralatetral areas, with its peak at seventy-two hours after occlusion, but that in penumbra and serum ascended. There were significant differences in MAO activities between ischemic group and control (P＜0.01). In ginkgolide B(GB) group, the MAO activities in all areas but not in core descended, significant differences(P＜0.01) between in GB group and in twenty-four hours after occlusion. Changes in MAO activity was consistent with alterations of brain proein content(r=0.81,P＜0.05). CONCLUSION:The changes in monoamine neurotransmitters in core and penumbra considerably depend on the alterations of MAO activities after thrombotically cerebral ischemia. Probably, protective effects of GB on ischemic neurons is related to its acting as antagonist of platelet activating factor and regulator of monoamine oxidase.