Brain and plasma cations and experimental seizures in normal and desoxycorticosterone-treated rats.

LTHOUGH clinical studies on the efficacy of desoxycorticosterone therapy A in epilepsy have yielded contradictory results (I, 2), in a few cases a significant decrease in the incidence of grand ma1 seizures has been noted (2). This improvement in the clinical status of the patients was apparently due to a retention of Na in the body, and a loss of K (3). Spiegel (4) administered desoxycorticosterone to rats but failed to observe a change in electrical stimulation. On the other hand, a growing the convulsive threshold to body of evidence indicates that the brain excitability of rats may be altered in a predictable manner by changes in the electrolyte balance of the body. Swinyard (5) has found a positive correlation between extracellular sodium concentration and electroshock seizure threshold in experimentally hydrated rats, and recent work in this laboratory (6) has demonstrated a lowered electroshock seizure threshold associated with low plasma Na levels in adrenalectomized rats. Evidence has also been presented which indicates that the refractory period following a major convulsion may be correlated with elevated plasma Na (7). In view of these observations it seemed esirable to reexamine the effect of desoxycorticosterone on brain excitability and to investigate the effects of excess Na, K, Ca and Mg.