Cyte-physiological study of abnormal Ca^<2+> metabolism in ischemic and epileptic neuronal death

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Functional changes in IP_33kinase knock-out miceIP_33-kinasemetabolizu IP_3 to 1,3,4,5-tetrakisphosphate (IP_4). Until recently physiological roles of IP_33-kinase or IP_4 are not well known. IP_33-kinase (A) is abundant in neuronal cells and IP_4 level in IP_33-kinase(A) deficient mice is significantly decreased. To know the role of IP_33-kinase or IP_4 in neuronal tissue, histochemical, behavioral and physiological study were performed using IP_33-kinase(A) deficient and wild type mice. In histochemical study with IP_33-kinase antibody, IP_33-kinase strongly express in hioppocampal CA1 region in normal gerbil. Passive avoidance with electric shocking chamber revealed less learning and memory function in IP_33-kinase(A) deficient mice. Hippocampal damage induced by global ischemia by 10 min common carotid occlusion did not show significant differences between IP_33-kinase(A) deficient and wild type mice. Intracellular Ca^<2+> increase following oxygen-glucose deprivation was also exam … More ined using hippocampal slice of deficient and wild type mice. These results suggest that IP_33-kinase and IP_4 have important roles in the process of learning and memory.Enhanced excitability on hippocampal CA3 in EL miceWe observed the changes in intracellular calcium on EL and control DDY mice hippocampal slice after oxygen-glucose deprivation (OGD) using calcium imaging with Rhod2-AM. In EL mice, the cytosolic calcium on hippocampal CA1, CA3 was significantly increased after OGD. On the contrary control DDY mice showed increase just on CA1 region. We also performed the same experiments in developing animals (2-8w) to know from when the hyper excitability in CA3 can be seen. In developing EL mice, calcium increase after OGD was less than the adults evenly in CA1 and CA3. The fluorescent intensity was successively increased in both CA1 and CA3 according to its age. These results suggest that the enhanced excitability on hippocampal CA3 in EL mice is obtained gradually according to the age. It is not a postgrowth acquisition. Less