Comparison of Fos Protein Expressions Rat Hippocampus Following Single and Repeated Intraperitoneal Administration of Kainic Acid

Kim, Kwang Soo; Yoo, Kyung Moo; Chang, Hee Kyung

Abstract

BACKGROUND:Acute seizures that increase neuronal activity cause a rapid and transient induction of the immmediate early c-fos in specific brain regions. C-fos gene may mediate long-term changes in cell function, such as growth, differeniation, and development, in response to acute extracellular stimulation. This study is designed to compare the expression of Fos protein in hippocampus after single and repeated injections of kainic acid (KA).
METHODS
In KA-single injection model, twelve adult male Sprague-Dawley rats were treated with single intraperitoneal injection of convulsive dose(20-30 mg/kg) of KA, and. in KA-multiple injections model, seven rats received KA by repeated daily intraperitoneal injections for 15 days. Eight control rats received normal saline. Expression of Fos protein was tested in hippocampus by immunohistochemical staining, and was scored by the degree of staining intensity and the ratio of stained cells to tested ones.
RESULTS
The scores tended to increase in CA3 and dentate gyrus were significantly higher in KA-single injection model than in control (p<0.05). In comparison with scores in KA-model.
CONCLUSION
These results show that repeated seizure produces some blockade of c-fos induction in CA2, CA3 and dentate gyrus. This may be a long-term adaptive response by the nervous system to repated neuronal activation