Immunohistochemical Study on the Distribution of Estrogen Receptor-alpha in the Hippocampus of the Normal Aged Rat

ABSTRACT

BACKGROUND: In recent years, estrogen has also been shown to modulate the development and function of the brain, bur not exclusively in areas involved with sexual behavior. Among the most novel and fascinating effects of estrogen are those on cognitive function and memory process and their alterations during aging and neurodegenarative disease like Alzheimer. Estrogen receptors distributed not only in the hypothalamus but many different areas, like cerebral cortex, hippocampus, basal forebrain, midbrain, spinal cord, and the diverse action of estrogen is supported by this fact. Numerous studies suggest thai estrogen may be beneficial in preserving cognitive function, but it is not clear yet. PURPOSE: In this study, we perform the immunohistochemical staining in the hippocampus of normal aged rat, and show the distribution of estrogen receptor compared with the neonatal rat. METHODS: we have used antibodies against a estrogen receptor(ER)-alpha to determine their distribution in neonatal and aged SD rat hippocampus. RESULTS: In neonatal rat hippocampus, ER-alpha immunoreactivity was observed in the nucleus of Purkinje cells, whereas in aged rat hippocampus, ER-a immunoreactivity was found mainly in the cytoplasm of Purkinje cells. CONCLUSION: We showed the age related intracellular differential distribution of ER-alpha immunoreactivity in the rat hippocampus. But, further investigations are required to establish whether functional relations like cognitive ability exist with this different intracellular expression of ER-alpha immunoreactivity.