Ohta R, Shirota M, Adachi T, Tohei A, Taya K
Laboratory of Reproductive and Developmental Toxicology, Hatano Research Institute, Kanagawa, Japan.
Behav Genet. 1999 Mar;29(2):137-44. doi: 10.1023/a:1021616723969.
Having successfully bred for high- and low-avoidance rats (HAA and LAA, respectively) on a shuttlebox task, we performed three experiments designed to identify factors which might be related to the phenotypic differences seen in avoidance behavior. In experiment 1, shuttlebox behavior was measured to determine whether the phenotypic difference was activity related. In terms of intertrial responses, there was no difference between HAA and LAA rats in locomotor activity during the conditioning process. Experiment 2 compared adrenal weights of HAA and LAA rats at 11 weeks of age. The observation that the adrenal glands were heavier in HAA than in LAA rats suggested that these strains might differ in aspects of endocrine response. In experiment 3, plasma levels of ACTH and corticosterone were determined during early escape/avoidance acquisition in the shuttlebox. Plasma levels of ACTH after the shuttlebox testing were higher in HAA than in LAA rats. There was no difference between the two strains in plasma levels of corticosterone after testing, possibly due to a ceiling effect. These results suggest that the phenotypic differences in the acquisition of avoidance behavior of HAA and LAA rats may be related to different endocrine responses, rather than to locomotor activity.
我们成功地在穿梭箱任务中培育出了高回避型和低回避型大鼠（分别为HAA和LAA），并进行了三项实验，旨在确定可能与回避行为中观察到的表型差异相关的因素。在实验1中，测量穿梭箱行为以确定表型差异是否与活动有关。就试验间期反应而言，在条件反射过程中，HAA和LAA大鼠在运动活动方面没有差异。实验2比较了11周龄时HAA和LAA大鼠的肾上腺重量。观察到HAA大鼠的肾上腺比LAA大鼠的更重，这表明这些品系在内分泌反应方面可能存在差异。在实验3中，在穿梭箱早期逃避/回避习得过程中测定了促肾上腺皮质激素（ACTH）和皮质酮的血浆水平。穿梭箱测试后，HAA大鼠的ACTH血浆水平高于LAA大鼠。测试后，两种品系在皮质酮血浆水平上没有差异，这可能是由于天花板效应。这些结果表明，HAA和LAA大鼠在回避行为习得方面的表型差异可能与不同的内分泌反应有关，而不是与运动活动有关。
