PATHOGENESIS OF SEIZURES OCCURRING DURING RESTORATION OF PLASMA TONICITY TO NORMAL IN ANIMALS PREVIOUSLY CHRONICALLY HYPERNATREMIC

Abstract

The present study describes the results of rehydration of rabbits rendered chronically hypernatremic by the administration of one molar sodium chloride solution by nasogastric tube for 23½ to 5 days. When these animals were rehydrated intravenously over a 4-hour period with 2.5% dextrose in water, returning the plasma sodium level to normal, 55% of them developed focal or generalized convulsions. The mean water content of brain tissue of the group of animals who had seizures was significantly greater than that of a normal group of animals and comparable to that found in a water-intoxicated group of animals. This elevation of water content could be accounted for by both an elevated content of potassium and chloride in the brain. The potassium content of the brain was higher in the rehydrated group of animals without than those with seizures. Ways by which the observed changes may be related to the development of seizures are discussed.