Sex differences in the stress responses in the amygdala

为了研究环境空间限制对海马乙酰胆碱（ACh）释放应激反应的影响，将雄性和雌性大鼠分别置于直径为35 cm的大圆柱笼和直径为19 cm的小圆柱笼中饲养4天后进行体内微透析研究。自由活动大鼠在1100 ~ 1600 h抽取透析液和血样，在1200 ~ 1300 h施加约束应激。大笼饲养的雄性大鼠对a - Ch释放的应激反应大于大笼饲养的雌性大鼠。此外，小笼雄性大鼠海马中乙酰胆碱释放的应激反应减弱，而小笼雌性大鼠海马中乙酰胆碱释放明显增加。我们推测，收容条件对海马乙酰胆碱释放应激反应的影响可能存在性别差异。为了研究基底外侧杏仁核（BLA）中5 -羟色胺（5HT）和多巴胺（DA）释放的应激反应的性别差异，我们在完整雄性大鼠和循环雌性大鼠（diestrus 2）体内进行了微透析研究。BLA的基础5HT释放较低，无性别差异。尽管雌雄大鼠的5HT释放随着约束应激的发生而迅速增加，但雄性大鼠的应激反应幅度明显小于雌性大鼠。相比之下，雄性大鼠BLA中DA的基础释放量高于雌性大鼠。虽然雌性大鼠的DA释放随着约束应激的发生而迅速增加，但雄性大鼠没有明显的应激反应。这些结果表明，性别和/或性腺类固醇激素环境可影响大鼠BLA中5HT和DA释放的应激反应。

To examine the effect of the restriction of environmental space on the stress response of the hippocampal acetylcholine (ACh) release, an in vivo microdialysis study was performed in male and female rats after 4-day housing in a large cylindrical cage (diameter = 35 cm) or a small cylindrical cage (diameter =19 cm). Dialysates and blood samples were taken from 1100 h to 1600 h in freely moving rats, but restraint stress was applied from 1200 h to 1300 h. Male rats living in a large cage showed greater stress response of the A Ch release than female rats living in a large cage. In addition, the stress response of ACh release in the hippocampus was attenuated in male rats living in a small cage, while female rats showed a significant increase in the ACh release in female rats living in a small cage. We surmise that there may be a sex difference in the effect of housing condition in the stress response of ACh release in the hippocampus.To examine the sex difference in the stress response of serotonin (5HT) and dopamine (DA) release in the basolateral amygdala (BLA), an in vivo microdialysis study was performed in intact male and cycling female (diestrus 2) rats. Basal 5HT release in the BLA was low without sex difference. Although the 5HT release promptly increased with the onset of the restraint stress in both sexes, the magnitude of the stress response in male rats was significantly less than in female rats. In contrast, male rats showed higher basal DA release in the BLA than female rats. Although the DA release promptly increased with the onset of the restraint stress in female rats, male rats showed no significant stress response. These results indicate that sex and/or gonadal steroid hormone environment can affect the stress response of 5HT and DA release in the BLA in rats.