DIFFERENT c- fos ACTIVATION IN RAT HIPPOCAMPAL CA1 NEURONS AND DENTATE GRANULE CELLS AFTER GLOBAL AND PRECONDITIONED CEREBRAL ISCHEMIA

摘要

We investigated the activation of c-fos early gene in the hippocampal region CA1 and gyrus dentatus in two groups of rats. The first group, exposed to global ischemia (during 10 minutes of occlusion of four vessels) was sacrificed 60 minutes after reperfusion, and the second group was first exposed to transient (3-4 minutes) ischemia (preconditioned or tolerant rats) and after 72 hours was again exposed to global ischemia in the same way as the first group. Immunohistochemistry for c-fos protein was performed using the avidin-biotin peroxidase method. Analysis of results included morphological, semiquantitative analysis and t-test of differences between GD and CA1 region of the hippocampus. Results showed a significantly more intense c-fos activation in GD than in the CA1 region in both groups, with global ischemia and preconditioned rats. This indicates different pattern of c-fos activation in investigated brain regions in relation to time factors, and also indicates a strong impact of ischemic preconditioning on c-fos activity in both investigated regions. Our results clearly show that in the future studies of c-fos activation in the brain a very careful experimental design related to the control of distinct regional and time effects needs to be performed.