Previous studies have shown that the anxiogenic effects of chronic stress do not correlate with dendritic remodeling in the central nucleus of the amygdala (CeA). We analyzed the effect of chronic restraint stress (CRS; 20 min/day for 14 days), relative to control (CTRL) conditions on anxiety-like behavior in the elevated plus maze (EPM) and the open field tests, and dendritic morphology, dendritic spine density and spine type numbers in pyramidal neurons of the CeA. Reversal of CRS-induced effects was explored in animals allowed a 14-day stress-free recovery after treatments. CRS decreased the frequency and time in the open arms and increased the anxiety index in the EPM, and reduced visits and time in the center of the open field. Morphological assays in these animals revealed no effect of CRS on dendritic complexity in CeA neurons; however, a decrease in dendritic spine density together with decreased and increased amounts of mushroom and thin spines, respectively, was detected. Subsequent to a stress-free recovery, a significant reduction in open arm entries together with an increased anxiety index was detected in CRS-exposed animals; open field parameters did not change significantly. A decreased density of total dendritic spines, in parallel with higher and lower numbers of thin and stubby spines, respectively, was observed in CeA neurons. Results suggest that CRS-induced anxiety-like behavior might be accounted for by a reduction in synaptic connectivity of the CeA. This effect, which is long lasting, could mediate the persisting anxiogenic effects of chronic stress after exposure to it has ended.

先前的研究表明，慢性压力的焦虑作用与杏仁核中央核 (CeA) 的树突重塑无关。我们分析了慢性约束压力（CRS；20 分钟/天，持续 14 天）相对于对照 (CTRL) 条件对高架十字迷宫 (EPM) 和旷场测试中的焦虑样行为以及树突形态的影响， CeA锥体神经元的树突棘密度和棘类型数。在动物中探索了 CRS 诱导作用的逆转，允许在治疗后 14 天无压力恢复。CRS 减少了张开双臂的频率和时间，增加了 EPM 中的焦虑指数，并减少了在开放场地中心的访问和时间。这些动物的形态学分析显示 CRS 对 CeA 神经元的树突复杂性没有影响。然而，检测到树突棘密度的降低以及蘑菇和细棘的数量分别减少和增加。在无压力恢复之后，在暴露于 CRS 的动物中检测到张开臂进入的显着减少以及焦虑指数的增加；开场参数没有显着变化。在 CeA 神经元中观察到总树突棘密度降低，同时细刺和粗刺的数量分别增加和减少。结果表明，CRS 引起的类似焦虑的行为可能是由于 CeA 的突触连接减少所致。这种持续时间长的效应可以在慢性压力结束后介导持续的焦虑作用。