1a–6a images (H&E ×100) of sagittal sections of rat brain hippocampus; 1b–6b images (H&E ×400) of CA3 region of rat brain hippocampus. CA1 Cornu ammonis1, CA2 Cornu ammonis2, CA3 Cornu ammonis3, DG dentate gyrus, mN myelinated neurons, D degeneration, V vacuolation, NN necrotic neurons