Faluhelyi Nándor, Csernus Valér
Department of Anatomy, Medical School, University of Pécs, Neurohumoral Regulations Research Group of the Hungarian Academy of Sciences, Pécs, Hungary.
Gen Comp Endocrinol. 2007 Jun-Jul;152(2-3):154-8. doi: 10.1016/j.ygcen.2007.01.022. Epub 2007 Jan 27.
The aim of this study was to monitor the changes in the pattern of the in vitro melatonin (MT) secretion under reversed illumination cycles with low intensity of light during photo phase. Although light is known to be one of the major synchronizing factors of the circadian MT rhythm in birds, there are no data available on the limits of direct light sensitivity of the avian pinealocytes. In our experiments, MT secretion from adult or from embryonic chicken pineal glands was monitored in a perifusion system for 4 days. The glands were repeatedly exposed to light with various intensities and duration. Reversed daily illumination inverted the in vitro MT rhythm even if the intensity of light was only 10lux at the surface of the perifusion columns. MT release of embryonic pineal glands was also found to be sensitive to dim light. Our results showed that the chicken pineal gland is directly sensitive to light of low intensity. However, the various oscillator units in the gland may have different sensitivity to dim light. Light perception mechanism in the chicken pinealocytes is already fully developed on the 17th embryonic day.
本研究的目的是监测在光照期低强度光照的反向光照周期下，体外褪黑素（MT）分泌模式的变化。虽然已知光为鸟类昼夜节律性MT节律的主要同步因素之一，但尚无关于禽类松果体细胞直接光敏感性限度的数据。在我们的实验中，在灌注系统中对成年或胚胎鸡松果体的MT分泌进行了4天的监测。松果体反复暴露于不同强度和持续时间的光照下。即使在灌注柱表面光照强度仅为10勒克斯，每日反向光照也会使体外MT节律反转。还发现胚胎松果体的MT释放对暗光敏感。我们的结果表明，鸡松果体对低强度光直接敏感。然而，松果体中的各种振荡器单元对暗光可能具有不同的敏感性。鸡松果体细胞中的光感知机制在胚胎第17天就已完全发育。
