Steimer T, Escorihuela R M, Fernández-Teruel A, Driscoll P
Dept. of Psychiatry, University of Geneva, Chêne-Bourg, Switzerland.
Int J Dev Neurosci. 1998 Jun-Jul;16(3-4):165-74. doi: 10.1016/s0736-5748(98)00032-x.
Roman high-(RHA/Verh) and low-(RLA/Verh) avoidance rats, originally selected and bred for rapid vs poor acquisition of a two-way active avoidance response, differ in emotional reactivity and coping style. These differences are associated with particular neuroendocrine and neurochemical characteristics. New data are presented here to show that the behavioural changes specifically induced by neonatal handling, i.e. decreased emotional reactivity, are associated with marked changes in the neuroendocrine responses of (hyperemotional) RLA/Verh rats to a novel environment. Eight months after neonatal handling, self-grooming behaviour, a reliable marker of emotional reactivity in this line of rats, was significantly decreased in RLA/Verh rats. Defecation scores were also significantly reduced in both lines. Moreover, there was a significant reduction in prolactin and corticosterone release following exposure to a novel environment in neonatally-handled RLA/Verh rats as compared to control, non-handled rats. No effects on prolactin and corticosterone release were observed in RHA/Verh rats. There was also no apparent effect of neonatal handling on coping style i.e. RLA/Verh rats did not increase their spontaneous exploration of novel environments. Thus, the phenotypic expression of basic traits of (high) neuroendocrine/emotional reactivity was specifically modulated by neonatal handling in RLA/Verh rats, whereas both the (hypoemotional) RHA/Verh rats as well as coping style in both lines remained unaffected. Changes in emotional reactivity were still apparent at 12 months of age when rats from the same groups were tested for hyponeophagia. These results suggest that psychogenetically selected lines such as RHA/RLA rats are suitable animal models to investigate interactions between genes and the environment in determining individual sensitivity to stress and coping styles, as well as potential vulnerability (or resistance) to the development of maladaptive syndromes similar to anxiety and mood disorders in humans.
罗马高回避（RHA/Verh）和低回避（RLA/Verh）大鼠最初是为了双向主动回避反应的快速获得与缓慢获得而选择培育的，它们在情绪反应性和应对方式上存在差异。这些差异与特定的神经内分泌和神经化学特征相关。本文呈现的新数据表明，新生期处理特异性诱导的行为变化，即情绪反应性降低，与（高度情绪化的）RLA/Verh大鼠对新环境的神经内分泌反应的显著变化有关。新生期处理8个月后，自我梳理行为（该品系大鼠情绪反应性的可靠指标）在RLA/Verh大鼠中显著降低。两个品系的排便分数也显著降低。此外，与未处理的对照大鼠相比，新生期处理的RLA/Verh大鼠暴露于新环境后，催乳素和皮质酮的释放显著减少。在RHA/Verh大鼠中未观察到对催乳素和皮质酮释放的影响。新生期处理对应对方式也没有明显影响，即RLA/Verh大鼠没有增加对新环境的自发探索。因此，（高）神经内分泌/情绪反应性基本特征的表型表达在RLA/Verh大鼠中受到新生期处理的特异性调节，而（低情绪化的）RHA/Verh大鼠以及两个品系的应对方式均未受影响。当对来自相同组的大鼠进行低食欲测试时，情绪反应性的变化在12个月大时仍然明显。这些结果表明，像RHA/RLA大鼠这样通过心理遗传学选择的品系是研究基因与环境在决定个体对应激的敏感性和应对方式以及对类似于人类焦虑和情绪障碍的适应不良综合征发展的潜在易感性（或抵抗力）之间相互作用的合适动物模型。
