Morgan D, Grant K A, Prioleau O A, Nader S H, Kaplan J R, Nader M A
Department of Physiology and Pharmacology, Wake Forest University School of Medicine, Winston-Salem, North Carolina 27157, USA.
Am J Primatol. 2000 Nov;52(3):115-31. doi: 10.1002/1098-2345(200011)52:3<115::AID-AJP1>3.0.CO;2-Z.
The purpose of the present study was to determine whether various behavioral and hormonal markers obtained in individually housed monkeys would be predictive of social rank following group housing. Body weight, serum cortisol and testosterone levels, and locomotor activity in an open-field apparatus were examined in 20 experimentally naive male cynomolgus monkeys (Macaca fascicularis) while they were individually housed. It was hypothesized that eventual subordinate monkeys would have higher cortisol levels and increased locomotor activity scores. These monkeys were then placed in social groups of four (five pens of four monkeys), and social rank was determined based on outcomes of dyadic agonistic encounters. Body weight correlated significantly with eventual social rank. In general, the heavier the monkey the higher the social rank. Locomotor activity in an open-field apparatus following administration of a low dose of cocaine (0.01 mg/kg, i.v.), which has been shown to increase CNS dopamine, correlated with eventual social rank such that individually housed monkeys with high levels of locomotion were more likely to become subordinate. Serum cortisol and testosterone levels failed to correlate with eventual social rank. Hypothalamic-pituitary feedback sensitivity and adrenal responsiveness were examined by measuring cortisol levels after administration of dexamethasone and following ACTH challenge. Cortisol responses in these tests were not associated with eventual social rank. These results suggest that, in addition to body weight, the level of reactivity in a novel environment after administration of a low dose of cocaine is a potential trait marker for social rank. This trait is apparently not associated with hormone levels, but may involve other CNS mechanisms.
本研究的目的是确定单独饲养的猴子所获得的各种行为和激素指标是否能预测群居后的社会等级。在20只从未接触过实验的雄性食蟹猴（猕猴）单独饲养期间，检测了它们的体重、血清皮质醇和睾酮水平以及在旷场装置中的运动活动。研究假设最终处于从属地位的猴子会有更高的皮质醇水平和更高的运动活动得分。然后将这些猴子分成每组四只的社会群体（五个围栏，每个围栏四只猴子），并根据二元争斗遭遇的结果确定社会等级。体重与最终的社会等级显著相关。一般来说，猴子越重，社会等级越高。给予低剂量可卡因（0.01mg/kg，静脉注射）后在旷场装置中的运动活动与最终的社会等级相关，低剂量可卡因已被证明可增加中枢神经系统多巴胺，单独饲养时运动水平高的猴子更有可能成为从属地位。血清皮质醇和睾酮水平与最终的社会等级无关。通过测量地塞米松给药后和促肾上腺皮质激素刺激后的皮质醇水平来检测下丘脑-垂体反馈敏感性和肾上腺反应性。这些测试中的皮质醇反应与最终的社会等级无关。这些结果表明，除体重外，低剂量可卡因给药后在新环境中的反应水平是社会等级的一个潜在特征标志物。该特征显然与激素水平无关，但可能涉及其他中枢神经系统机制。
