Testing whether adrenal steroids mediate phenotypic and physiologic effects of elevated salinity on larval tiger salamanders
Testing whether adrenal steroids mediate phenotypic and physiologic effects of elevated salinity on larval tiger salamanders
复制标题
测试肾上腺类固醇是否介导盐度升高对虎蝾幼体的表型和生理影响
DOI：
10.1111/1749-4877.12669
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发表时间：
2022
影响因子：
3.3
通讯作者：
HOSSACK, Blake R.
中科院分区：
文献类型：
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作者：
TORNABENE, Brian J.;CRESPI, Erica J.;BREUNER, Creagh W.;HOSSACK, Blake R.
人为来源的盐度（氯化钠）是一种持久性污染物，对淡水类群产生负面影响。两栖动物可能对盐度敏感，但有些物种天生或适应性耐受。调节耐盐性的生理机制尚不清楚，但调节激素如皮质酮（CORT）和醛固酮（ALDO）的变化是主要候选者。我们将幼斑虎蝾螈（Ambystoma mavortium）暴露于环境相关的NaCl处理（<32-4000 mg/L）24天，以测试对生长，存活和水生CORT反应的影响。在这些采样中，我们还从一个子集中定量了水载ALDO。使用糖皮质激素拮抗剂（RU 486），我们还通过实验抑制了一些幼虫的CORT信号传导，以确定CORT是否介导盐度的影响。盐度处理之间的生存没有很强的差异，但盐度降低干质量，口鼻长度，和身体状况，而增加幼虫的含水量。高存活率和亚致死效应表明，蝾螈在生理上受到挑战，但可以耐受实验浓度。CORT信号并没有减弱盐度的亚致死效应。基线和应激诱导的（急性应激源，摇晃后）CORT不受盐度的影响。ALDO与基线CORT相关，表明CORT和ALDO的作用可能难以分离。未来的研究比较ALDO和CORT反应的适应性耐受和以前未暴露的人群可能有利于了解这些激素在耐盐性的作用。然而，我们的研究增强了我们对皮质类固醇激素在介导一个突出的人为压力源的作用的理解。
Salinity (sodium chloride, NaCl) from anthropogenic sources is a persistent contaminant that negatively affects freshwater taxa. Amphibians can be susceptible to salinity, but some species are innately or adaptively tolerant. Physiological mechanisms mediating tolerance to salinity are still unclear, but changes in osmoregulatory hormones such as corticosterone (CORT) and aldosterone (ALDO) are prime candidates. We exposed larval barred tiger salamanders (Ambystoma mavortium) to environmentally relevant NaCl treatments (<32–4000 mg·L−1) for 24 days to test effects on growth, survival, and waterborne CORT responses. Of those sampled, we also quantified waterborne ALDO from a subset. Using a glucocorticoid antagonist (RU486), we also experimentally suppressed CORT signaling of some larvae to determine if CORT mediates effects of salinity. There were no strong differences in survival among salinity treatments, but salinity reduced dry mass, snout–vent length, and body condition while increasing water content of larvae. High survival and sublethal effects demonstrated that salamanders were physiologically challenged but could tolerate the experimental concentrations. CORT signaling did not attenuate sublethal effects of salinity. Baseline and stress‐induced (after an acute stressor, shaking) CORT were not influenced by salinity. ALDO was correlated with baseline CORT, suggesting it could be difficult to decouple the roles of CORT and ALDO. Future studies comparing ALDO and CORT responses of adaptively tolerant and previously unexposed populations could be beneficial to understand the roles of these hormones in tolerance to salinity. Nevertheless, our study enhances our understanding of the roles of corticosteroid hormones in mediating effects of a prominent anthropogenic stressor.