Abstract: AIM: To observe the effects and mechanism of naloxone being injected intra-cere broventricular on studying and memory in mice with repeatedly cerebral ischemia reperfusion.METHODS: Double-tube was embedded in lateral ventricle of mice, anti-infection was taken for 4 or 5 days to mice after operation, and the repeated cerebral ischemia reperfusion model was made in awakening mice.Behavior of learning and memory was observed by eletic maze test, methylenedioxy (MDA) in brain tissue was detected by TBA, the content of β-Ep in brain tissue and blood plasma was measured by radio-immunity method, and the number of cell was counted in htppcoampal CA1 on section of brain tissue.RESULTS: Naloxone obviously improved the disorder of studying and memory of mice, and inhibited the abnormal increased MDA and β-Ep in brain tissue caused by repeated cerebral ischemia.It also improved the number of cell in htppcoampal CA1.CONCLUTION: Naloxone can protect mice being repeatedly cerebral ischemia reperfusion from the damage of studying and memory, and its mechanism is related to its contradicting β-Ep activity and lowing MDA in brain and increased htppcoampal CA1.

Key words: intra-cerebroventricular injection, repeated cerebral ischemia-reperfusion, naloxone hydrochloride, studying and memory, malonydialdehyde (MDA), β-endorphin ;, htppcoampal CA1