Institute of Biology, Department of Integrative Zoology, Leiden University, The Netherlands.
Behav Brain Res. 2012 Mar 17;228(2):367-74. doi: 10.1016/j.bbr.2011.12.016. Epub 2011 Dec 19.
One of the most commonly used behavioral endpoints measured in preclinical studies using rodent models is thigmotaxis (or "wall-hugging"). Thigmotaxis is a well-validated index of anxiety in animals and humans. While assays measuring thigmotaxis in adult zebrafish have been developed, a thigmotaxis assay has not yet been validated in larval zebrafish. Here we present a novel assay for measurement of thigmotaxis in zebrafish larvae that is triggered by a sudden change in illumination (i.e. sudden light-to-darkness transition) and performed in a standard 24-well plate. We show that zebrafish larvae as young as 5 days post fertilization respond to this challenge by engaging in thigmotaxis. Thigmotaxis was significantly attenuated by anxiolytic (diazepam) and significantly enhanced by anxiogenic (caffeine) drugs, thus representing the first validated thigmotaxis assay for larval zebrafish. We also show that exposure to sudden darkness per se may represent an anxiogenic situation for larval zebrafish since less contrasting light-to-darkness transitions (achieved by lowering darkness degrees) significantly decreased thigmotaxis levels in a manner similar to what was achieved with diazepam. These findings suggest that stimuli such as exposure to sudden darkness could be used proficiently to trigger the expression of anxiety-like behaviors in laboratory settings. In sum, this is a versatile protocol allowing testing of both anxiolytic and anxiogenic drugs in a cost-effective manner (only 10 min). This assay is also amenable to medium to high-throughput capacity while constituting a valuable tool for stress and central nervous system research as well as for preclinical drug screening and discovery.
在使用啮齿动物模型进行的临床前研究中，最常使用的行为终点之一是触壁行为（或“壁贴”）。触壁行为是动物和人类焦虑的一种经过充分验证的指标。虽然已经开发出用于测量成年斑马鱼触壁行为的测定法，但尚未在斑马鱼幼虫中验证触壁行为测定法。在这里，我们提出了一种新颖的测定斑马鱼幼虫触壁行为的方法，该方法是由光照的突然变化（即突然从亮到暗的转变）触发的，并在标准的 24 孔板中进行。我们表明，受精后 5 天的幼鱼对这种挑战做出反应，通过触壁行为来应对。这种行为被抗焦虑药（地西泮）显著减弱，而被焦虑药（咖啡因）显著增强，因此代表了第一个针对斑马鱼幼虫的经过验证的触壁行为测定法。我们还表明，突然的黑暗本身可能代表着对幼鱼的焦虑情况，因为较不明显的明暗过渡（通过降低黑暗程度来实现）以类似于地西泮的方式显著降低了触壁行为的水平。这些发现表明，突然暴露于黑暗等刺激可能会在实验室环境中有效地触发类似焦虑的行为表达。总之，这是一种多功能的方案，可以以经济有效的方式测试抗焦虑药和焦虑药（仅需 10 分钟）。该测定法还适用于中高通量，同时构成了压力和中枢神经系统研究以及临床前药物筛选和发现的有价值的工具。
