Effects of systemic kainic acid administration on regional Na+, K+-ATPase activity in rat brain.

Changes in the activity of Na+,K+-ATPase and in the water, Na+, and K+ levels in the parietal cortex, hippocampus, and thalamus were investigated in rats 1, 3, 6, and 24 h following systemic kainic acid injection. An increase in Na+,K+-ATPase activity was observed in all three regions 3 h after the treatment, with a subsequent decrease in enzyme activity. The elevation in Na+,K+-ATPase activity was accompanied by an increase in the Na+ content and a decrease in the K+ content. These changes are presumed to occur because of repeated discharges and excessive prolonged depolarization in response to kainic acid. The decreases in Na+,K+-ATPase activity 6 and 24 h following kainic acid treatment coincide with neuropathological damage and edema formation, mainly in the hippocampus and thalamus.