Shors T J, Chua C, Falduto J
Department of Psychology and Center for Collaborative Neuroscience, Rutgers University, Piscataway, New Jersey 08854, USA.
J Neurosci. 2001 Aug 15;21(16):6292-7. doi: 10.1523/JNEUROSCI.21-16-06292.2001.
Dendritic spines are postsynaptic sites of excitatory input in the mammalian nervous system. Despite much information about their structure, their functional significance remains unknown. It has been reported that females in proestrus, when estrogen levels are elevated, have a greater density of apical dendritic spines on pyramidal neurons in area CA1 of the hippocampus than females in other stages of estrous (Woolley et al., 1990). Here we replicate these findings and in addition, show that females in proestrus have a greater density of spines in area CA1 of the hippocampus than males. Moreover, this sex difference in spine density is affected in opposite directions by stressful experience. In response to one acute stressful event of intermittent tailshocks, spine density was enhanced in the male hippocampus but reduced in the female hippocampus. The decrease in the female was observed for those that were stressed during diestrus 2 and perfused 24 hr later during proestrus. The opposing effects of stress were not evident immediately after the stressor but rather occurred within 24 hr and were evident on apical and to a lesser extent on basal dendrites of pyramidal cells in area CA1. Neither sex nor stress affected spine density on pyramidal neurons in somatosensory cortex. Sex differences in hippocampal spine density correlated with sex hormones, estradiol and testosterone, whereas stress effects on spine density were not directly associated with differences in the stress hormones, glucocorticoids. In summary, males and females have different levels of dendritic spine density in the hippocampus under unstressed conditions, and their neuronal anatomy can respond in opposite directions to the same stressful event.
树突棘是哺乳动物神经系统中兴奋性输入的突触后位点。尽管关于它们的结构已有很多信息，但它们的功能意义仍然未知。据报道，在动情前期雌激素水平升高时，雌性大鼠海马体CA1区锥体细胞顶端树突棘的密度比处于动情周期其他阶段的雌性大鼠更高（伍利等人，1990年）。在此，我们重复了这些发现，此外，还表明动情前期的雌性大鼠海马体CA1区的棘密度比雄性大鼠更高。此外，这种棘密度的性别差异会受到应激经历的相反影响。在经历一次间歇性尾部电击的急性应激事件后，雄性大鼠海马体中的棘密度增加，而雌性大鼠海马体中的棘密度降低。对于在动情后期2受到应激并在动情前期24小时后进行灌注的雌性大鼠，观察到了这种降低。应激的相反作用在应激源作用后并未立即显现，而是在24小时内出现，并且在CA1区锥体细胞的顶端树突上明显，在基底树突上的影响较小。性别和应激均未影响体感皮层锥体细胞上的棘密度。海马体棘密度的性别差异与性激素雌二醇和睾酮相关，而应激对棘密度的影响与应激激素糖皮质激素的差异没有直接关联。总之，在无应激条件下，雄性和雌性大鼠海马体中的树突棘密度水平不同，并且它们的神经元结构对同一应激事件的反应可能相反。
