The relationship between metal ion levels and biogenic amine levels in epileptic mice

Abstract

The metabolism of various metal ions and biogenic amines in El mice, an inbred mutant strain susceptible to epilepsy, was investigated as a possible model for seizure mechanism. Serum Na, P, Ca, Mg, Fe and Zn levels in El mice were lower than those in ddY mice, the mother strain of El mice. Conversely, bone Ca, P, Na, Mg and Zn levels in El mice were higher than those in ddY mice. The results obtained by chemical analysis are consistent with radiographic observations. Possible mechanisms for the lower serum metal ion levels seen in El mice include a decrease in availability of these ions from bone. The dopamine (DA) level in El mouse brain was 15% lower than in ddY mice but could be raised by intraventricular administration of CaCl2. This result was supported a decreased ethanol-induced sleeping time in El as compared to ddY mice, with 'normalization' occurring after intraventricular administration of Da or CaCl2. The biogenic amine levels disorder in El mice is discussed on the basis of our pharmacological observation that biogenic amine synthesis is regulated by divalent cations via a calmodulin-dependent system. Our results suggest that the disorders of metal ion metabolism could be a mechanism for epileptic convulsions in El mice.