ABSTRACT
PURPOSE: The expression of c-Fos protein has been shown to be a useful marker for elevated levels of neuronal activity generated in the brain following different stimuli, including seizures. This study was conducted to investigate distribution and numbers of neurons where dentate and cingulate gyrus become activated following pentylenetetrazol-induced seizures by means of expression patterns of c-Fos protein. METHODS: Rats were sacrificed at increasing times(1 hour, 2 hours, 8 hours, 1 day, 4 days and 7 days) after pentylenetetrazol-induced seizure. Rat brains were removed and sliced in rat brain matrix. Brain slices were coronal sectioned at interaural 5.70-6.70mm. Serial sections were immunohistochemically reacted with polyclonal c-Fos antibody. The distribution and numbers of c-Fos protein immunoreactive neurons in dentate gyrus and cingulate gyrus were examined and analyzed statistically with Mann-Whitney U test. RESULTS: The numbers of c-Fos protein immunoreactive neurons in dentate gyrus peaked at 1 hours and reached almost normal conditions at 7 days after seizure. Also, same patterns were occurred in cingulate gyrus. Concentration value that pentylenetetrazol can induce was different from each animals and c-Fos immunoreactive cells were various kinds of neurons. CONCLUSION: Higher numbers of c-Fos protein immunoreactive neurons were found in dentate and cingulate gyrus at the same times after seizure. These findings suggest that neurons of dentate and cingulate gyrus play a crucial role in seizure onset following pentylenetetrazol-induced seizure.