脑缺血时大鼠大脑皮层乙酰胆碱含量变化的动态观察

本实验采用双侧颈总动脉夹闭（ＣＣＡＯ）和大脑中动脉闭塞（ＭＣＡＯ）两种脑缺血动物模型，分别用乙酰胆碱（ＡＣｈ）生物测定法检测皮层ＡＣｈ含量，ＡＣｈ离子选择性微电极（ＡＣｈ－ＩＳＭｓ）检测皮层ＡＣｈ释放量，乙酰胆碱酯酶（ＡＣｈＥ）生化测定法检测皮层ＡＣｈＥ活性，观察脑缺血时皮层ＡＣｈ含量的动态查化。结果发现：脑缺血可诱发皮层ＡＣｈ活度急剧上升，示ＡＣｈ突然大量释放，在ＣＣＡＯ组于缺血１０ｍｉｎ达到高峰（净增１．４４４ｍｍｏｌ／Ｌ），而ＭＣＡＯ组于缺血２ｍｉｎ即达高峰（净增１．５５３ｍｍｏｌ／Ｌ），随着缺血延长，二者均逐渐下降，于缺血３０ｍｉｎ时，虽较峰值要低，但明显高于缺血前水平，此时，ＡＣｈＥ活性巳明显低于缺血前，ＡＣｈ含量在ＣＣＡＯ组下降０．２５６μｇ／ｇ（Ｐ＞０．０５），在ＭＣＡＯ组则显著下降１．０１４μｇ／ｇ（Ｐ＜０．０１）。结果提示：皮层ＡＣｈ含量变化对缺血是敏感的；脑缺血时ＡＣｈ含量下降、释放增加、降解减弱，推测ＡＣｈ可能在缺血性脑损伤中起重要作用。

DYNAMIC OBSERVATION ON CHANGES OF ACETYLCHOLINE IN RAT CEREBRAL CORTEX DURING CEREBRAL ISCHEMIA

The present study applied acetylcholine (ACh) bioassay to measure ACh content.acetylcholinesterase (AChE) biochemical method to determine AChE activity and ACh ion selective microelectrodes (ACh-ISMs) to measure ACh output in rat cerebral cortex, clarified changes of ACh in ischemic cortex induced by two rat models of cerebral ischemia - common carotid artery occlusion (CCAO), middle cerebral artery occlusion (MCAO). The results showed ACh output increased to peak in 10 min after ischemia induced by CCAO (raised 1.444 mmol/ L netly), but to summit in 2 min after MCAO (raised 1.553 mmol/ L netly). However ACh cutout appeared a trend to decline along with lengthening of ischemia in two models.30 min after ischemia, ACh activities were lower than peak, but high than per-ischemia's, ACh contents and AChE activities were low to pre-ischemia's. This research indicated that ACh in rat cerebral cortex was sensitive to ischemia; the falled extent of ACh content and the raised velocity of ACh output were positively correlative to the degree of cerebral ischemia; ACh could take some important effects on ischemic brain injury.