Glutamic acid, γ-aminobutyric acid and glial fibrillary acidic protein positive cells in the hippocampus of El mice and ddY mice were examined immunohistochemically. The shape of glutamic acid positive cells in CA1, CA2, CA3 and CA4 of hippocampus were expanded compared to that of ddY mice. There was a space between cells and cells containing glutamic acid and the nucleus of such cells was larger in the CA1 of El mice than that of ddY mice. The glutamic acid cells were irregular and the nucleus was larger in the gyrus dentatus of El mice than that of ddY mice. There was an intermittence in the process of glutamic acid cells in the area of str. radiatum of El mice. γ-Aminobutyric acid-positive cells seemed to be expanded in CA1, CA2, CA3, and CA4 and gyrus dentatus and there was space between such cells in the CA1 of El mice. Large γ-aminobutyric acid positive cells, which were located close to the gyrus dentatus in ddY mice, were not found in El mice. The number of γ-aminobutyric acid-positive cells was lower in El mice than in ddY mice. A greater number of glial fibrillary acidic protein positive cells was found in the area of the hippocampus in El mice than in ddY mice. These results suggest that El mice are genetically epileptic mice.
