---

Background and Objective: The findings of various research indicated that there are different responses to painful thermal stimulation in male and female Rats. In different estrous phases there are different pain thershold border line due to hormonal reaction. Regarding to anti-nociceptive effect of henbane seed. This study was designed to assess the anti-nociceptive afficacy of alcohole extract of henbane seed in different phases of estroes cycle of female Rates. Materials and Methods: In this experimental study 92 female NMRI strain rats weighing 195-220 grams randomly were divided into three, control, experimental and positive groups. Male Rats (n=8) were chosen as control group. To measure the threshold of acute pain, all animals were exposed to the tail immersion test using 52 degree c water. In the experimental group, alcoholic extract of henbane seed (2000 mg/kg) was injected, intraperitoneally, 25-30 minutes before the tail immersion test. Afterwards, in the all of control and experimental groups of female rats the smear samples were taken to determine the sexual phases. In addition, the analgesic effect of henbane was compared with anti-nociceptive effect of sodium salicylate (300 mg/kg). Results: Injection of alcoholic extract of henbane seed, diminished the tail immersion test-induced acute pain in female rats significantly (P<0.05). also, no significant differences of analgesic effect of henbane extract were seen among various phases of estrous cycle in female rats. There is no significant differences of analgesia between henbane and salicylate-treated groups. Conclusion: This study determined that female rats in different phases of estrous cycle have similar pain thresholds and the alcoholic extract of henbane seed is effective in the relief of pain in the various phases of estrous cycle.

---

Background and Objective: Neurogenesis is the process through which neurons are generated from neural stem cells. This process has been shown to occur in special zones of the adult brain including the subventricular zone (SVZ) of the lateral ventricles and the dentate gyrus of the hippocampus. Gonadal steroids affect different steps of neurogenesis, and cell proliferation seems to be increased by estrogens. This study aimed to investigate the neurogenic changes in the SVZ at different phases of the estrous cycle.
Methods: In this experimental study, 26 NMRI mice were used. The mice were identified by vaginal smear and then divided into 4 groups including proestrus (n=5), estrous (n=7), metestrus (n=7) and diestrous (n=7). Different stages of the estrous cycle were determined by staining vaginal smears. Also, the qualitative assessment of cell proliferation in the SVZ was performed by cresyl fast violet staining and glial fibrillary acidic protein (GFAP) immunohistochemistry at different stages of the estrous cycle.
Results: In microscopic sections stained with cresyl violet, it was observed that cell density in the proestrus stage of the estrous cycle was greater than in any other stages of the estrous cycle. A comparison of sections stained with anti-GFAP showed that the density of astrocytes in proestrus was significantly higher than in other groups.
Conclusion: Proestrus stage of the estrous cycle is associated with increased cell proliferation and density of astrocytes in the SVZ of mice. Neurogenesis is correlated to changes in sex hormonal levels at different phases of the estrus cycle.