Department of Psychology and Center for Neuroscience, University of Colorado, Boulder, CO, USA.
Neuroscience. 2010 Feb 17;165(4):1031-8. doi: 10.1016/j.neuroscience.2009.11.005. Epub 2009 Nov 10.
Experience with behavioral control over tailshock (escapable shock, ES) has been shown to block the behavioral and neurochemical changes produced by later uncontrollable tail shock (inescapable shock, IS). The present experiments tested, in rats, whether the protective effect of control over tailshock extends beyond reducing the behavioral and neurochemical impact of a subsequent tailshock experience to stressors that are quite different. Social defeat (SD) was chosen as the second stress experience because it has few if any cues in common with tailshock. SD produced shuttlebox escape learning deficits ("learned helplessness") and reduced juvenile social investigation 24 h later, as does IS. IS is notable for inducing a large increase in dorsal raphe nucleus (DRN) serotonergic (5-HT) activity as measured by extracellular levels of 5-HT within the DRN, and SD did so as well. ES occurring 7 days before SD blocked this SD-induced DRN activation, as well as the SD-induced interference with shuttlebox escape and reduction in social investigation. Prior exposure to yoked IS did not reduce the DRN 5-HT activation or later behavioral effects produced by SD, and thus the proactive stress-blunting effects of ES can be attributed to it's controllability. Thus, ES confers a very general protection to the impact of a subsequent stress experience.
已经证明，对尾部电击（escapable shock，ES）的行为控制经验可以阻止随后的不可控尾部电击（inescapable shock，IS）引起的行为和神经化学变化。本实验在大鼠中测试了，尾部电击的控制的保护作用是否不仅限于减轻后续尾部电击经历对压力源的行为和神经化学影响，而且还扩展到了与尾部电击几乎没有共同线索的压力源。选择社会挫败（social defeat，SD）作为第二种应激体验，因为它与 IS 一样，会产生穿梭箱逃避学习缺陷（“习得性无助”），并在 24 小时后减少幼年社交探索。IS 显著诱导中缝核（dorsal raphe nucleus，DRN）5-羟色胺能（5-HT）活性的大量增加，如 DRN 内 5-HT 的细胞外水平所示，SD 也是如此。ES 在 SD 前 7 天发生，可阻断 SD 诱导的 DRN 激活，以及 SD 诱导的穿梭箱逃避干扰和社交探索减少。先前暴露于偶联 IS 并没有减少 DRN 5-HT 激活或随后 SD 引起的行为效应，因此 ES 的主动压力缓冲效应可以归因于它的可控性。因此，ES 为随后的应激体验的影响提供了非常普遍的保护。
