Distribution of trace elements in the brain of EL (epilepsy) mice

The association of essential trace elements with epileptic seizures is poorly understood. On the basis of the evidences that the release of zinc from the brain of epilepsy (EL) mice, an animal model of genetically determined epilepsy, is enhanced by the induction of seizures and that alteration of zinc homeostasis is responsive to susceptibility to seizures, the distribution of trace elements in the brain was studied using EL mice and ddY mice, which form the genetic background for the inbred EL mice. The multitracer technique was applied to determine the distribution of trace elements. Twenty-four hours after intravenous injection of the multitracer, the concentration of ⁶⁵Zn and ⁵⁶Co in the brain of untreated EL mice was higher than in ddY mice, while the concentration of ⁶⁵Zn and ⁵⁶Co in the brain was decreased in seized EL mice. ⁷⁵Se concentration in the hippocampus, cerebral cortex and cerebellum of untreated EL mice was lower than in ddY mice, while ⁷⁵Se concentration in the hippocampus was increased in seized EL mice. ⁸³Rb, an element of homologous series to potassium, concentration in the hippocampus and cerebral cortex of untreated EL mice was lower than in ddY mice, and ⁸³Rb concentration in the cerebral cortex was decreased in seized EL mice. The movement of zinc, cobalt and selenium in the brain may be altered by enhancement of susceptibility to seizures. These results suggest that alteration of homeostasis of zinc, cobalt and selenium in the brain may be involved in the susceptibility, development or termination of seizures in EL mice.