King J A, Edwards E
Department of Psychiatry, University of Massachusetts Medical Center, Worcester, Massachusetts, 01655, USA.
Horm Behav. 1999 Oct;36(2):79-85. doi: 10.1006/hbeh.1999.1525.
During early development, environmental challenges set the stage for permanent changes in the functioning of the pituitary-adrenal stress response. Since these data have been reported almost exclusively in single rat strains the role of phenotypic and genotypic factors in shaping the stress response is relatively unknown. This study examined whether the phenotypic/genetic profile of the rat influences the long-term response to challenge after early exposure to stress. Two strains of Sprague-Dawley rats were used in this study: one is a stress-induced animal model of "learned helpless" (LH) behavior and the other a resistant strain developed through selective breeding. Stress-induced adrenocorticotropic hormone (ACTH) and corticosterone release was monitored in adult congenital learned helpless (cLH) rats and congenital non-learned helpless (cNLH) rats. The rats were exposed to cold stress or maternal deprivation (on either postnatal day 7 or day 21). After the early acute stress exposure, animals remained undisturbed until challenged in adulthood (day 90) with footshock stress. In cLH animals (adults) early cold stress (particularly after acute stress on postnatal day 21) and maternal deprivation stress resulted in an enhancement of stress-induced ACTH release compared to nonstressed cLH and cNLH controls. In contrast, adrenal responsiveness was generally suppressed in cLH animals that were acutely stressed with cold stress or maternal deprivation stress early in life. The above results suggest that the genetic/phenotypic profile of the animal is a determinant in the changes observed in the adult stress response after early exposure to stressors.
在早期发育过程中，环境挑战为垂体 - 肾上腺应激反应功能的永久性改变奠定了基础。由于这些数据几乎完全是在单一大鼠品系中报道的，因此表型和基因型因素在塑造应激反应中的作用相对未知。本研究探讨了大鼠的表型/遗传特征是否会影响早期暴露于应激后对挑战的长期反应。本研究使用了两种斯普拉格 - 道利大鼠品系：一种是“习得性无助”（LH）行为的应激诱导动物模型，另一种是通过选择性育种培育出的抗性品系。监测成年先天性习得性无助（cLH）大鼠和先天性非习得性无助（cNLH）大鼠应激诱导的促肾上腺皮质激素（ACTH）和皮质酮释放。大鼠暴露于冷应激或母体剥夺（出生后第7天或第21天）。在早期急性应激暴露后，动物一直未受干扰，直到成年期（第90天）受到电击应激挑战。在cLH动物（成年）中，早期冷应激（特别是出生后第21天急性应激后）和母体剥夺应激导致与未应激的cLH和cNLH对照相比，应激诱导的ACTH释放增强。相比之下，在生命早期受到冷应激或母体剥夺应激急性应激的cLH动物中，肾上腺反应性通常受到抑制。上述结果表明，动物的遗传/表型特征是早期暴露于应激源后成年应激反应中观察到的变化的一个决定因素。
