Stressor-specific activation of the hypothalamic-pituitary-adrenocortical axis.
Stressor-specific activation of the hypothalamic-pituitary-adrenocortical axis.
复制标题
下丘脑-垂体-肾上腺皮质轴的应激源特异性激活。
作者：
K. Pacak
新的信息已经积累了从在体微透析研究室旁核（PVN）和下丘脑-垂体-肾上腺皮质（HPA）轴的激活细胞外液中去甲肾上腺素浓度的应激相关变化。我们的数据的影响，下脑干半切表明，室旁去甲肾上腺素能终端主要来自髓质A1和A2的儿茶酚胺能细胞。这些细胞的激活对清醒动物室旁核应激诱导的去甲肾上腺素能激活有重要贡献。脑干半切实验的结果还表明，基线水平和制动诱导的增量促肾上腺皮质激素释放激素（CRH）mRNA表达的PVN依赖于同侧升髓束。因此，普遍的概念，应激诱导的HPA轴的去甲肾上腺素能激活主要取决于激活蓝斑去甲肾上腺素能神经元需要重新评估。我们新的压力概念有利于HPA轴的应激特异性激活。目前的数据还表明存在的压力特异性的中央通路，差异参与交感神经元和肾上腺髓质流出的调节，以及HPA轴的活动。此外，这些结果与Selye压力理论的创始原则不一致，即非特异性原则，该原则将压力定义为身体对任何需求的非特异性反应。我们预计，在这一领域的未来研究将集中在进一步检查的概念，应激特异性模式的中枢神经递质释放和阐明这些模式的遗传基础。
New information has accrued from in vivo microdialysis studies about stress-related changes in norepinephrine concentrations in extracellular fluid of the paraventricular nucleus (PVN) and the activation of the hypothalamic-pituitary-adrenocortical (HPA) axis. Our data on the effects of lower brainstem hemisections show that paraventricular noradrenergic terminals are derived mainly from medullary A1 and A2 catecholaminergic cells. The activation of these cells contributes importantly to stress-induced noradrenergic activation in the paraventricular nucleus of conscious animals. The results from brainstem hemisection experiments also indicate that baseline levels and immobilization-induced increments in corticotropin-releasing hormone (CRH) mRNA expression in the PVN depend on ipsilaterally ascending medullary tract. Thus, the prevalent concept that stress-induced noradrenergic activation of the HPA axis depends mainly on activation of locus ceruleus noradrenergic neurons requires re-evaluation. Our new stress concepts favor stressor-specific activation of the HPA axis. The present data also suggest the existence of stressor-specific central pathways that differentially participate in the regulation of sympathoneuronal and adrenomedullary outflows as well as of the activity of the HPA axis. Furthermore, the results are inconsistent with a founding tenet of Selye's stress theory, the doctrine of nonspecificity, which defines stress as the nonspecific response of the body to any demand. We expect that future studies in this area will focus on further examination of the notion of stressor-specific patterns of central neurotransmitter release and elucidate the genetic bases of these patterns.