School of Biological Sciences, University of Liverpool, Liverpool, UK, L69 7ZB.
Horm Behav. 2011 Jan;59(1):67-74. doi: 10.1016/j.yhbeh.2010.10.010. Epub 2010 Oct 19.
Bold, risk-taking animals have previously been putatively linked with a proactive stress coping style whereas it is suggested shyer, risk-averse animals exhibit a reactive coping style. The aim of this study was to investigate whether differences in the expression of bold-type behaviour were evident within and between two lines of rainbow trout, Oncorhynchus mykiss, selectively bred for a low (LR) or high (HR) endocrine response to stress, and to link boldness and stress responsiveness with the expression of related candidate genes. Boldness was determined in individual fish over two trials by measuring the latency to approach a novel object. Differences in plasma cortisol concentrations and the expression of eight novel candidate genes previously identified as being linked with divergent behaviours or stress were determined. Bold and shy individuals, approaching the object within 180 s or not approaching within 300 s respectively, were evident within each line, and this was linked with activity levels in the HR line. Post-stress plasma cortisol concentrations were significantly greater in the HR line compared with the LR line, and six of the eight tested genes were upregulated in the brains of LR fish compared with HR fish. However, no direct relationship between boldness and either stress responsiveness or gene expression was found, although clear differences in stress physiology and, for the first time, gene expression could be identified between the lines. This lack of correlation between physiological and molecular responses and behavioural variation within both lines highlights the complexity of the behavioural-physiological complex.
先前有假设认为，大胆、冒险的动物与积极的压力应对方式有关，而较胆小、回避风险的动物则表现出被动的应对方式。本研究的目的是探究在两种虹鳟鱼品系（经选择性繁殖，对压力的内分泌反应分别较低（LR）和较高（HR））中，是否存在大胆行为表现的差异，以及将大胆行为和压力反应性与相关候选基因的表达联系起来。通过测量鱼接近陌生物体的潜伏期，在两次试验中分别对个体的大胆程度进行了测定。测定了两种品系的血浆皮质醇浓度差异和之前确定与不同行为或压力相关的 8 个新候选基因的表达情况。在每条鱼的品系内都可以看到大胆和胆小的个体，前者在 180 秒内接近物体，后者在 300 秒内不接近物体，这与 HR 品系的活动水平有关。与 LR 品系相比，HR 品系的应激后血浆皮质醇浓度显著升高，而且在 LR 鱼的大脑中，有 6 个被测试的基因表达上调，而在 HR 鱼的大脑中则没有。然而，在 HR 品系和 LR 品系中，都没有发现大胆行为与应激反应性或基因表达之间存在直接关系，尽管可以清楚地分辨出两种品系之间在应激生理学上存在差异，这是首次发现。这种行为-生理综合复杂性的特点是，在两种品系中，生理和分子反应与行为变化之间缺乏相关性。
