Zeman Michal, Szántóová Kristína, Herichová Iveta
Department of Animal Physiology and Ethology, Comenius University Bratislava, Mlynská dolina B2, 842 15 Bratislava, Slovak Republic.
Comp Biochem Physiol A Mol Integr Physiol. 2009 Sep;154(1):78-83. doi: 10.1016/j.cbpa.2009.05.005. Epub 2009 May 15.
The circadian system drives postnatally rhythmic processes in the peripheral tissues. To extend information about embryonic stages, ontogeny of the circadian oscillations in chicken (Gallus gallus) heart and liver was analyzed. Nineteen day old embryos and 4-day old chicks were synchronized to a light:dark cycle and then the effects of light pulses applied during the dark and subjective light phases of the 24 h cycle were tested. Expression of Per2 and Bmal1 was measured by RT-PCR. The effects of light pulses on plasma glucose and melatonin levels were also analyzed. The expression of Per2 and Bmal1 was rhythmic in the heart and liver of 4-day old chicks, however, more pronounced rhythmic expression was observed in the liver. The light pulse induced a significant increase in Per2 expression in the liver. Plasma glucose was up- and melatonin down-regulated after the light pulse postnatally. Expression of Per2 did not show a rhythmic pattern and the light pulse did not cause changes in Per2 expression in the liver and heart of the embryos. The absence of the rhythmic expression of the clock genes in the embryonic heart and liver may reflect missing rhythmic cues since early after hatching peripheral oscillators function in a mature-like manner.
昼夜节律系统驱动出生后外周组织中的节律性过程。为了扩展有关胚胎阶段的信息，分析了鸡（原鸡）心脏和肝脏中昼夜节律振荡的个体发生。将19日龄胚胎和4日龄雏鸡同步到明暗周期，然后测试在24小时周期的黑暗和主观光照阶段施加光脉冲的影响。通过RT-PCR测量Per2和Bmal1的表达。还分析了光脉冲对血浆葡萄糖和褪黑激素水平的影响。Per2和Bmal1的表达在4日龄雏鸡的心脏和肝脏中呈节律性，但在肝脏中观察到更明显的节律性表达。光脉冲诱导肝脏中Per2表达显著增加。出生后光脉冲后血浆葡萄糖上调而褪黑激素下调。Per2的表达在胚胎的肝脏和心脏中未显示出节律模式，并且光脉冲未引起Per2表达的变化。胚胎心脏和肝脏中时钟基因节律性表达的缺失可能反映了自孵化后早期外周振荡器以成熟样方式发挥作用以来节律线索的缺失。
