Ballaz Santiago J, Akil Huda, Watson Stanley J
Molecular and Behavioral Neuroscience Institute, University of Michigan, Ann Arbor, MI 48109-0720, USA.
Behav Neurosci. 2007 Oct;121(5):1113-8. doi: 10.1037/0735-7044.121.5.1113.
Novelty-seeking behavior in rats is deemed to model sensation seeking in humans, a personality trait related to some psychiatric conditions, including substance abuse. Animals characterized based on their locomotor response to novelty, namely high and low responders (HRs and LRs, respectively), show differences in anxiety and drug-taking behaviors. This study evaluates the effect of anxiety-provoking situations on subsequent behaviors in these endophenotypes. Selectively bred HR and LR rats were submitted to blocks of tests consisting of two-trial light- dark (LD) and two-trial elevated plus maze (EPM) tests arranged in counterbalanced, alternating order. No differences in anxiety-like behaviors were found in HR-bred and LR-bred rats in either LD trial, regardless of the test order. Repeated exposure to the EPM test, however, resulted in enhanced behavioral response under different test orders as a function of endophenotype. Compared with HR-bred animals, LR-bred animals exhibited increased anxiety on reexposure to EPM but only if both trials were preceded by an LD test session. The emotional responses in HR-bred and LR-bred rats reported here may reflect different degrees of adaptive processing regulated by both genetic and environmental factors.
大鼠的新奇寻求行为被认为是人类感觉寻求的模型，感觉寻求是一种与某些精神疾病相关的人格特质，包括药物滥用。根据动物对新奇事物的运动反应进行分类，即高反应者和低反应者（分别为HRs和LRs），它们在焦虑和药物摄取行为上存在差异。本研究评估了引发焦虑的情境对这些内表型后续行为的影响。选择性培育的HR和LR大鼠接受了一系列测试，包括两次明暗试验（LD）和两次高架十字迷宫试验（EPM），试验以平衡、交替的顺序进行。在LD试验中，无论试验顺序如何，HR品系和LR品系的大鼠在焦虑样行为上均未发现差异。然而，重复暴露于EPM试验中，根据内表型的不同，在不同的试验顺序下行为反应增强。与HR品系的动物相比，LR品系的动物在再次暴露于EPM时表现出焦虑增加，但前提是两次试验之前都有一次LD试验。此处报道的HR品系和LR品系大鼠的情绪反应可能反映了由遗传和环境因素调节的不同程度的适应性加工。
