Effects of estrogen on GABA and P38 in the hippocampus of PTZ-induced epileptic rats

Aim: To study effects of estrogen on GABA and P38 in the hippocampus of menstrual epilepsy rats ,and this will supply the basis for the mechanisms that estrogen enhances epileptic seizures. Methods: Estrogen-replace therapy was used ,and epileptic seizures were induced by PTZ in ovaiectomized SD female rats. GABA and P38 immunoreactive products were observed in different brain areas of dorsal hippocampus of rats. Results: 1) Results of GABA immunohistochemistry:GABA positive neurons significantly decreased in hila of dorsal hippocampus of OVX rats in PTZ treated groups as compared with control groups.There was also significantly decrease of GABA positive neurons in E2 treated groups as compared with PTZ treated groups. 2)Immunoreactive products of P38 observation: In stratum oriens and stratum radiatum of CA1 area and stratum lucidum of CA3, the immunoactive intensities had no significant changes in control group compared with PTZ treated group and stronger in E2 treated group compared with PTZ treated group. However, that of molecular layer of dentate gyrus had no significant changes among three groups. Conclusion:1) Behavior observation indicated that the estrogen enhanced significantly epileptic seizures. 2) The estrogen reduced the quantity of GABA in hilus area of dorsal hippocampus,thereby lowered the inhibiting ability of GABA on epileptic seizure, and enhanced epileptic seizures sensibility. 3)Estrogen increased the contents of P38 in stratum oriens and stratum radiatum of CA1 and stratum lucidum of CA3 (which meaned the increase of synaptic density). That increased the release of excitable neurotransmitters which enhanced the excitability in hippocampus. That might be one of the mechanisms of estrogen effects on the enhancement of epileptic susceptibility.