Saiz Nuria, Gómez-Boronat Miguel, De Pedro Nuria, Delgado María Jesús, Isorna Esther
Fish Neuroendocrinology Group, Department of Genetics, Physiology and Microbiology, Faculty of Biology, Complutense University of Madrid, 28040 Madrid, Spain.
Animals (Basel). 2021 Mar 3;11(3):669. doi: 10.3390/ani11030669.
Vertebrates possess circadian clocks, driven by transcriptional-translational loops of clock genes, to orchestrate anticipatory physiological adaptations to cyclic environmental changes. This work aims to investigate how the absence of a light-dark cycle and a feeding schedule impacts the oscillators in the hypothalamus-pituitary-interrenal axis of goldfish. Fish were maintained under 12L:12D feeding at ZT 2; 12L:12D feeding at random times; and constant darkness feeding at ZT 2. After 30 days, fish were sampled to measure daily variations in plasma cortisol and clock gene expression in the hypothalamus-pituitary-interrenal (HPI) axis. Clock gene rhythms in the HPI were synchronic in the presence of a light-dark cycle but were lost in its absence, while in randomly fed fish, only the interrenal clock was disrupted. The highest cortisol levels were found in the randomly fed group, suggesting that uncertainty of food availability could be as stressful as the absence of a light-dark cycle. Cortisol daily rhythms seem to depend on central clocks, as a disruption in the adrenal clock did not impede rhythmic cortisol release, although it could sensitize the tissue to stress.
脊椎动物拥有生物钟，由生物钟基因的转录-翻译循环驱动，以协调对周期性环境变化的预期生理适应。这项工作旨在研究缺乏明暗周期和进食时间表如何影响金鱼下丘脑-垂体-肾间轴中的振荡器。将鱼饲养在以下条件下：在ZT 2时12小时光照：12小时黑暗并定时投喂；12小时光照：12小时黑暗并随机时间投喂；以及在ZT 2时持续黑暗并定时投喂。30天后，对鱼进行采样，以测量下丘脑-垂体-肾间（HPI）轴中血浆皮质醇的每日变化和生物钟基因表达。在有明暗周期的情况下，HPI中的生物钟基因节律是同步的，但在没有明暗周期的情况下则消失了，而在随机投喂的鱼中，只有肾间生物钟受到干扰。在随机投喂组中发现了最高的皮质醇水平，这表明食物供应的不确定性可能与缺乏明暗周期一样具有压力。皮质醇的每日节律似乎依赖于中枢生物钟，因为肾上腺生物钟的破坏并没有阻碍皮质醇的节律性释放，尽管它可能使组织对压力更敏感。
