TY - JOUR T1 - The Effects of Tamoxifen on Ultrastructure and the Number of Hippocampal Cells in Rat’s Fetus and Neonate TT - اثرات تاموکسیفن بر فراساختار و تعداد سلولهای هیپوکامپ جنین و نوزاد The Effects of Tamoxifen on Ultrastructure and the Number of Hippocampal Cells in Rat’s Fetus and Neonate JF - RJMS JO - RJMS VL - 13 IS - 53 UR - http://rjms.iums.ac.ir/article-1-664-en.html Y1 - 2007 SP - 185 EP - 195 KW - Key Words: 1) Hippocampus 2) Tamoxifen 3) Development 4) Estrogen 5) Rat N2 -     Background & Aim: Maternal steroids modulate various functions in the brain. However, tamoxifen(TAM) treatment, as an estrogen antagonist, induces cell death in the hippocampus formation of a prenatal and postnatal rat. Estrogen influences cognitive functions, learning process, aging, vasodilation, angiogenesis, neurogenesis and neuroprotection. The present study deals with the effects of tamoxifen on ultrastructure and morphology of developing hippocampus in rats. Material & Method: In this experimental study, we examined twelve bands of rats in three groups of control, experimental and sham. In each group, there were four age ranges: full-term embryo(E22), one-day newborn(P1), seven-day newborn (P7), and three-week newborn(P21). Full-term animals received four doses of tamoxifen in propylene glycol and their brains were removed 6 hours after the last injection. We studied hippocampal regions such as CA1, CA3, D.G. and subiculum through light and electron microscopy. Statistical significance of the differences was assessed by ANOVA and t-test using SPSS program. A value of P M3 ER -