催产素对基线惊吓反应高或低的大鼠背景焦虑的影响。
Effects of oxytocin on background anxiety in rats with high or low baseline startle.
作者信息
Ayers Luke, Agostini Andrew, Schulkin Jay, Rosen Jeffrey B
机构信息
Department of Psychology, Widener University, Chester, PA, USA.
Department of Psychological and Brain Sciences, University of Delaware, Newark, DE, USA.
出版信息
Psychopharmacology (Berl). 2016 Jun;233(11):2165-2172. doi: 10.1007/s00213-016-4267-0. Epub 2016 Mar 23.
RATIONALE
Oxytocin has antianxiety properties in humans and rodents. However, the antianxiety effects have been variable.
OBJECTIVES
To reduce variability and to strengthen the antianxiety effect of oxytocin in fear-potentiated startle, two experiments were performed. First, different amounts of light-shock pairings were given to determine the optimal levels of cue-specific fear conditioning and non-predictable startle (background anxiety). Second, the antianxiety effects of oxytocin were examined in rats with high and low pre-fear conditioning baseline startle to determine if oxytocin differentially affects high and low trait anxiety rats.
METHODS
Baseline pre-fear conditioning startle responses were first measured. Rats then received 1, 5, or 10 light-shock pairings. Fear-potentiated startle was then tested with two trial types: light-cued startle and non-cued startle trials. In the second experiment, rats fear conditioned with 10 light-shock pairings were administered either saline or oxytocin before a fear-potentiated startle test. Rats were categorized as low or high startlers by their pre-fear conditioning startle amplitude.
RESULTS
Ten shock pairings produced the largest non-cued startle responses (background anxiety), without increasing cue-specific fear-potentiated startle compared to one and five light-shock pairings. Cue-specific fear-potentiated startle was unaffected by oxytocin. Oxytocin reduced background anxiety only in rats with low pre-fear startle responses.
CONCLUSIONS
Oxytocin has population selective antianxiety effects on non-cued unpredictable threat, but only in rats with low pre-fear baseline startle responses. The low startle responses are reminiscent of humans with low startle responses and high trait anxiety.
原理
催产素对人类和啮齿动物具有抗焦虑特性。然而，其抗焦虑作用存在差异。
目的
为减少变异性并增强催产素在恐惧增强惊吓反应中的抗焦虑作用，进行了两项实验。首先，给予不同数量的光-电击配对，以确定线索特异性恐惧条件反射和不可预测惊吓（背景焦虑）的最佳水平。其次，在恐惧条件反射前惊吓反应基线高低不同的大鼠中研究催产素的抗焦虑作用，以确定催产素是否对高低特质焦虑大鼠有不同影响。
方法
首先测量恐惧条件反射前的基线惊吓反应。然后大鼠接受1次、5次或10次光-电击配对。随后用两种试验类型测试恐惧增强惊吓反应：线索性惊吓试验和非线索性惊吓试验。在第二个实验中，对经过10次光-电击配对进行恐惧条件反射的大鼠，在恐惧增强惊吓试验前给予生理盐水或催产素。根据恐惧条件反射前的惊吓幅度将大鼠分为低惊吓反应组或高惊吓反应组。
结果
与1次和5次光-电击配对相比，10次电击配对产生了最大的非线索性惊吓反应（背景焦虑），且未增加线索特异性恐惧增强惊吓反应。线索特异性恐惧增强惊吓反应不受催产素影响。催产素仅降低了恐惧条件反射前惊吓反应低的大鼠的背景焦虑。
结论
催产素对非线索性不可预测威胁具有群体选择性抗焦虑作用，但仅在恐惧条件反射前基线惊吓反应低的大鼠中如此。低惊吓反应让人联想到惊吓反应低且特质焦虑高的人类。
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