Program in Neurogenetics, Florida Atlantic University, Jupiter, Florida.
Department of Biological Science, Florida Atlantic University, Jupiter, Florida.
J Exp Zool B Mol Dev Evol. 2020 Nov;334(7-8):486-496. doi: 10.1002/jez.b.22987. Epub 2020 Aug 6.
Stress responses are conserved physiological and behavioral outcomes as a result of facing potentially harmful stimuli, yet in pathological states, stress becomes debilitating. Stress responses vary considerably throughout the animal kingdom, but how these responses are shaped evolutionarily is unknown. The Mexican cavefish has emerged as a powerful system for examining genetic principles underlying behavioral evolution. Here, we demonstrate that cave Astyanax have reduced behavioral and physiological measures of stress when examined at larval stages. We also find increased expression of the glucocorticoid receptor, a repressible element of the neuroendocrine stress pathway. Additionally, we examine stress in three different cave populations, and find that some, but not all, show reduced stress measures. Together, these results reveal a mechanistic system by which cave-dwelling fish reduced stress, presumably to compensate for a predator poor environment.
应激反应是生物体面对潜在有害刺激时产生的一种保守的生理和行为反应，但在病理状态下，应激反应会变得衰弱。应激反应在动物界中差异很大，但这些反应是如何进化形成的还不得而知。墨西哥洞穴鱼已成为研究行为进化背后遗传原理的有力系统。在这里，我们证明了在幼虫阶段，洞穴拟丽鱼的应激行为和生理指标降低。我们还发现糖皮质激素受体的表达增加，这是神经内分泌应激途径的一个可抑制元件。此外，我们还研究了三个不同洞穴种群的应激反应，发现其中一些种群（但不是全部）表现出应激反应指标降低。总之，这些结果揭示了一种机制系统，洞穴栖息的鱼类通过这种系统来降低应激，可能是为了补偿缺乏捕食者的环境。
