engleski

Changes of the hippocampal Na+K+-ATPase activity in rats with global cerebral ischemia and kainic acid-induced seizures

Introduction: Na+K+-ATPase is highly concentrated in neuronal cell membranes and is important for cellular integrity and function. Since its activity is very sensitive to even small changes in the plasma membrane lipid microenvironment, the early and late stages of tissue injury can be studied by measuring its activity. Therefore, the purpose of this study was to investigate the changes of the hippocampal Na+K+-ATPase activity in rats exposed to global cerebral ischemia or in rats with kainic acid-induced seizures. Materials and Methods: Global cerebral ischemia of 20-min duration was induced by the four-vessel occlusion method (Pulsinelli and Brierly, 1979). The animals were sacrificed immediately, 0.5, 1, 2, 6, 24, 48, 72 or 168 h after ischemic procedure. The level of the Na+K+-ATPase activity was measured during all reperfusion periods examined. The enzymatic activity from the hippocampal tissue was also determined 2 h, 3 and 5 days after single KA injection (8 mg/kg). Results: The global cerebral ischemia induced the significant decline in the Na+K+-ATPase activity in the hippocampus starting from 1 to 168 h of reperfusion. Maximal inhibition was obtained 24 h after the ischemic damage. In the model of kainic acid-induced seizures the Na+K+-ATPase activity was significantly decreased the 3rd and 5th day after drug administration. Conclusion: The Na+K+-ATPase hippocampal activity has been changed in the conditions of global cerebral ischemia and kainic acid-induced seizures. The observed enzymatic changes could be used as the parameters of tissue damage in mentioned experimental conditions.

hippocampal Na+K+-ATPase activity; global cerebral ischemia; kainic acid-induced seizures; rat

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