Changes in somatostatin immunoreactive neurons in rat cerebral cortex after systemic kainic acid administration

ABSTRACT

This study was aimed to clarify the effects of systemic kainic acid (KA) administration (10 mg/kg i.p.) on somatostatin containing neurons, and to examine the distribution of somatostain immunoreactive neurons in the cerebral cortex of the rats. Animals were sacrificed at three time points at the two, six, and ten days after the injection of KA. Thirty-six rats were observed by using the free-floating immunohistochemical method (modified ABC method). The results were as follows 1) In the anterior and posterior cingulate cortex, somatostatin immunoreactive neurons were not observed in 2,6,10days after treatment of KA including control group except Cg 1 showing some somatostatin immunoreactive neurons in 10days and control groups. 2) In the insular cortex, somatostatin immunoreactive neurons also were not observed in any groups except AIV showing few somatostatin immunoreactive neurons in control group. 3) In the perirhinal cortex, few somatostatin immunoreactive neurons were observed in 2 days and 6 days groups. In control group, a number of somatostatin immunoreactive neurons observed. 4) A strong decrease of somatostatin immunoreactive neurons were observed in the frontal, arietal, temporal and occipital cortex 2 days after treatment of KA. Initially decreased somatostatin immunoreactive neurons had recovered to control 10 days after treatment. 5) Distribution of the somatostatin immunoreactive neurons was observed marked difference according to the cortical areas. Somatostatin immunoreactive neurons in isocortex were more increased in number than the allcotex by control study. The changes in somatostatin immunoreactive neurons after systemic treament of KA were marked in 2 days and 6 days, but these had recovered to control 10 days the treatment of KA. It suggested the normalization of the cerebral function 10 days after seizure. According to the cerebral cortex, the different distribution of somatostatin immunoreactive neurons in number was observed.