Status epilepticus induced by pilocarpine and Ca2+ transport by microsome in the hippocampus of rats

Abstract

An increase in intra-neuronal Ca2+ concentration has been associated to status epilepticus (SE). Ca2+ is stored in the endoplasmic reticulum, mediated by the Ca2+-ATPases (SERCAs). Here we studied the Ca2+-ATPase activity and the SERCA2b distribution in the hippocampus of rats submitted to 5 h of SE. the Ca2+-uptake was measured using [Ca-45]CaCl2 and the hippocampal distribution of SERCA2b was analyzed by immunohistochemistry. A reduction in the amount of cells expressing SERCA2b in CA1, CA3 and dentate gyrus was observed. However, the surviving cells of these regions increased the SERCA2b immunoreactivity, when compared with control tissues. the Ca2+-ATPase activity measured in all hippocampal formation was not modified by SE. These results suggest that SE promotes a redistribution of SERCA2b in the hippocampus as a compensatory Ca2+-transport mechanism. (C) 2004 Elsevier Ireland Ltd. All fights reserved.