Falconer Erin M, Galea Liisa A M
Department of Psychology, University of British Columbia, Vancouver, Canada.
Brain Res. 2003 Jun 13;975(1-2):22-36. doi: 10.1016/s0006-8993(03)02542-3.
Males show suppressed cell proliferation in the hippocampus in response to acute stress but no studies to date have examined cell proliferation in response to acute stress in females. In the current study, we examined the effects of acute exposure to a predator odor stressor [trimethyl thiazoline (TMT); the main component of fox feces] or a control odor on cell proliferation and cell death in the dentate gyrus and on behavior in adult male and female [intact, ovariectomized (OVX) or OVX+estradiol benzoate (EB)] rats. Further, we examined whether TMT-induced changes in behavior were related to cellular changes. During TMT exposure, rats were injected with the cell synthesis marker bromodeoxyuridine and perfused 24 h later. Acute TMT exposure suppressed both cell proliferation and death in males but not in any group of females. Interestingly, in the OVX females we observed an increase in cell death that was eliminated by EB treatment. Consistent with prior studies, estradiol treatment increased cell proliferation regardless of odor condition. Regardless of sex or hormone treatment, TMT increased defensive behavior, suggesting that the behavioral response to TMT is dissociated from this cellular response. This is the first demonstration of a sex difference in cell proliferation and death in the adult dentate gyrus in response to stress.
雄性在急性应激反应下海马体中的细胞增殖受到抑制，但迄今为止尚无研究考察雌性在急性应激反应下的细胞增殖情况。在本研究中，我们检测了成年雄性和雌性[完整、去卵巢（OVX）或去卵巢+苯甲酸雌二醇（EB）]大鼠急性暴露于捕食者气味应激源[三甲基噻唑啉（TMT）；狐狸粪便的主要成分]或对照气味后，对齿状回中细胞增殖、细胞死亡及行为的影响。此外，我们还检测了TMT诱导的行为变化是否与细胞变化有关。在TMT暴露期间，给大鼠注射细胞合成标记物溴脱氧尿苷，并在24小时后进行灌注。急性TMT暴露抑制了雄性的细胞增殖和死亡，但对任何一组雌性均无此作用。有趣的是，在去卵巢雌性大鼠中，我们观察到细胞死亡增加，而EB处理可消除这种增加。与先前的研究一致，无论气味条件如何，雌二醇处理均可增加细胞增殖。无论性别或激素处理如何，TMT均增加防御行为，这表明对TMT的行为反应与这种细胞反应无关。这是首次证明成年齿状回在应激反应下细胞增殖和死亡存在性别差异。
