动物通常会遇到环境(例如,高温和缺氧)以及生理扰动(例如,运动和消化)可能威胁体内平衡。然而,比较不同压力源施加的相对威胁或“破坏性”是困难的,由于压力源的机制各不相同,影响,和时间尺度。我们利用了以下事实:几种急性应激源可以引起鱼类的平衡丧失(LOE),以(i)比较三种与环境相关的应激源的代谢恢复概况,以及(ii)测试LOE可以用作生理校准的概念。不同压力源的强度。我们关注的是喉部回肠,一种经常应对温度和氧气环境波动的物种,依靠爆发游泳来重新定位和避开捕食者,作为我们的模型。使用停流(间歇性)呼吸测量法,我们跟踪氧消耗率(MO2)作为E.caeruleum恢复从LOE诱导的缺氧(PO2在LOE),变暖(临界热最大值,CTmax),或详尽的练习。不管使用什么压力源,E.快速恢复,在〜3小时内恢复到常规MO2。从缺氧和变暖中恢复的鱼具有相似的最大MO2,有氧范围,恢复时间,以及缺氧后或升温后总过量耗氧量。尽管力竭运动比变暖或缺氧引起更大的最大MO2和相应的更高的有氧范围,它的恢复情况与其他压力源相似,这表明“校准”到一个生理状态,如LOE可能是一个可行的概念方法,研究者感兴趣的问题与多种压力源,交叉公差,以及动物如何应对稳态的挑战。
Animals routinely encounter environmental (e.g., high temperatures and hypoxia) as well as physiological perturbations (e.g., exercise and digestion) that may threaten homeostasis. However, comparing the relative threat or \"disruptiveness\" imposed by different stressors is difficult, as stressors vary in their mechanisms, effects, and timescales. We exploited the fact that several acute stressors can induce the loss of equilibrium (LOE) in fish to (i) compare the metabolic recovery profiles of three environmentally relevant stressors and (ii) test the concept that LOE could be used as a physiological calibration for the intensity of different stressors. We focused on Etheostoma caeruleum, a species that routinely copes with environmental fluctuations in temperature and oxygen and that relies on burst swimming to relocate and avoid predators, as our model. Using stop-flow (intermittent)
respirometry, we tracked the oxygen consumption rate (MO2) as E. caeruleum recovered from LOE induced by hypoxia (PO2 at LOE), warming (critical thermal maximum, CTmax), or exhaustive exercise. Regardless of the stressor used, E. caeruleum recovered rapidly, returning to routine MO2 within ~3 h. Fish recovering from hypoxia and warming had similar maximum MO2, aerobic scopes, recovery time, and total excess post-hypoxia or post-warming oxygen consumption. Though exhaustive exercise induced a greater maximum MO2 and corresponding higher aerobic scope than warming or hypoxia, its recovery profile was otherwise similar to the other stressors, suggesting that \"calibration\" to a physiological state such as LOE may be a viable conceptual approach for investigators interested in questions related to multiple stressors, cross tolerance, and how animals cope with challenges to homeostasis.