Astrocytic response in hippocampus and cerebral cortex in an experimental epilepsy model.

Astrocytes are very sensitive to alterations in the brain environment and respond showing a phenomenon known as astroglial reaction. S100beta is an astroglial derived neurotrophic factor, seems to be involved in neuroplasticity. The aim of this work was to study the astrocytic response in rat hippocampus and cerebral cortex after repetitive seizures induced by 3-mercaptopropionic acid (MP) administration. Immunocytochemical studies were performed to analyze GFAP and S100beta expression. Both studied areas showed hypertrophied astrocytes with enlarged processes and increased soma size. Astrocyte hyperplasia was observed only in the cerebral cortex. A significant decrease in the astrocytic S100beta immunostaining occurs after MP treatment. These results indicate that MP administration induces an astroglial reaction with reduced intracellular S100beta level. The observed reduction in astroglial S100beta could be related to the release of this factor to the extracellular space, where it may produce neurotrophic or deleterious effects accordingly to the concentration achieved. The mechanism of this remains to be elucidated.