Decrease in level of APG-2, a member of the heat shock protein 110 family,in murine brain following systemic administration of kainic acid

APG-2 belongs to the heat shock protein 110 family. Although kainic acid (K A)-induced seizures are known to elicit expression of inducible heat shock protein 70 (HSP70) in the brain, no investigation has been carried out on t he APG-2 level after excitatory amino acid-induced seizures. By means of an immunoblot assay, we determined the levels of HSP70 and APG-2 in discrete brain structures of mice after a single intraperitoneal injection of KA or N-methyl-D-aspartic acid NMDA). APG-2 level was significantly decreased in frontal cortex, hippocampus, and striatum three days after the administrati on of KA, while HSP70 level was increased in these regions following the ad ministration. ln any of these regions, APG-2 levels were returned to the co ntrol levels 10 days after the administration. However, no significant chan ges were observed in levels of both HSP70 and APG-2 in hypothalamus, midbra in, medulla-pons, and cerebellum of the mice. By contrast, NMDA administrat ion did not significantly affect both levels in any of the regions examined . These findings indicate that the transient decrease in APG-2 expression i s one of the intracellular events elicited by signals peculiar to KA, but n ot by those peculiar to NMDA, in telencephalon of murine brain. (C) 2001 El sevier Science Ltd. All rights reserved.