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Studies on mechanism of the inhibition of Ca~(2+)/CaM PKII activity induced by hypoxia in rat hippocampal slices

Pei Lin, Zong Yanyan, Zhang Lei, Sun Yafeng, Zhang Guangyi

The Research Center of Biochemistry and Molecular Biology, Xuzhou Medical College. Xuzhou 221002,Jiangsu

Abstract

The effects of Ca~(2+) and ketamine on Ca~(2+)/CaM PKII activity in rat hippocampal slices under in vitro hypoxic states have been studied and the effect of hypoxia on glutamate accumulation was also investigated. The results were as follows: (1) Ca~(2+)/CaM PKII activity decreased gradually with increasing hypoxic time in culture medium with or without 1.3 Ca~(2+) mmol/L, with the former case being much more pronounced. (2) Extracelluar accumulation of GLU increased about two-fold after hypoxia for 30 min in vitro. (3) When slices were incubated for 30 min under conditions in excess ofexogenous GLU the enzyme activity markedly decreased, a finding suggesting that the inhibition of enzymeactivity induced by hypoxia may result from excitotoxicity. (4) The inhibition of the enzyme activity induced by either hypoxia orexcess exogenous glutamate alone could be antagonized markedly by pretreatment with ketamine, suggesting that the hypoxia induced inhibition of the enzyme activity is mediated by NMDA receptor.

Key words: Ca~(2+);Hippocampal slice;Hypoxia;Ketamine;Ca~（2+）/CaM PK Ⅱ

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Citing This Article：

Pei Lin, Zong Yanyan, Zhang Lei, Sun Yafeng, Zhang Guangyi. Studies on mechanism of the inhibition of Ca~(2+)/CaM PKII activity induced by hypoxia in rat hippocampal slices. Acta Physiol Sin 1997; 49 (1): (in Chinese with English abstract).