|
|
Significance of the timekeeping system for human health
Pospíšilová, Lucie ; Sumová, Alena (advisor) ; Hejnová, Lucie (referee)
The circadian system evolved as an adaptation to cyclic changes in external conditions on Earth, mainly the alternation of light and dark with a period of solar day. The rhythmic signal is generated at the cellular level and it is controlled by rhythmic expression of clock genes and their protein products. In mammals, the hypothalamic suprachiasmatic nuclei (SCN) are the principal circadian oscillator coordinating daily cycles of physiology and behavior, while in peripheral tissues local oscillators operate. The peripheral oscillators are entrained to the daytime and also among each other, by neuroendocrine signals from the SCN. Mutual synchrony of all the circadian components is necessary for proper function of the organism. The main entraining cue of the circadian system with environment is light, which affect the SCN via retina. In a subgroup of blind people sensing the light in the retina is disturbed and their circadian system cannot be synchronized by light. The SCN controls rhythmic production of melatonin in the pineal gland. This hormone mediates the information about the daytime to other tissues in the body, which are not photosensitive. The circadian system temporally drives many processes, including the cell division cycle. It seems that disruption of the temporal regulation could contribute to...
|
|
|
Development of the rat circadian system under constant light conditions
Petrželková, Lucie ; Bendová, Zdeňka (advisor) ; Kopřivová, Jana (referee)
The circadian system is a mechanism designed to generate circadian time and to synchronize it with the solar cycle. Its function is to adjust to behavioral and physiological function with the 24-hour period. The adjustment is performed using a so-called zeitgeber or synchronizer. The main circadian clock is in the suprachiasmatic nuclei (SCN) in the hypothalamus. Prolonged exposure of the organism to constant light conditions results in desynchronization of the circadian clock, which can lead to many pathologies. The impact of light at night on the organism has been studied for a long time, but the question of the impact of constant light on the development of the circadian system of the organism has been less studied. My thesis deals with this issue. Using RT-qPCR I investigated how the rhytm changes in the expression of selected clock genes in selected parts of the rat's brain, which has been kept in constant light sice birth. I also tested the impact of exposure to constant light on the early development of rhytm in locomotor activity later in the rat's life. Keywords: circadian system, photic entrainment, desynchronization under constant light, development, rat
|
|
|
Significance of the timekeeping system for human health
Pospíšilová, Lucie ; Sumová, Alena (advisor) ; Hejnová, Lucie (referee)
The circadian system evolved as an adaptation to cyclic changes in external conditions on Earth, mainly the alternation of light and dark with a period of solar day. The rhythmic signal is generated at the cellular level and it is controlled by rhythmic expression of clock genes and their protein products. In mammals, the hypothalamic suprachiasmatic nuclei (SCN) are the principal circadian oscillator coordinating daily cycles of physiology and behavior, while in peripheral tissues local oscillators operate. The peripheral oscillators are entrained to the daytime and also among each other, by neuroendocrine signals from the SCN. Mutual synchrony of all the circadian components is necessary for proper function of the organism. The main entraining cue of the circadian system with environment is light, which affect the SCN via retina. In a subgroup of blind people sensing the light in the retina is disturbed and their circadian system cannot be synchronized by light. The SCN controls rhythmic production of melatonin in the pineal gland. This hormone mediates the information about the daytime to other tissues in the body, which are not photosensitive. The circadian system temporally drives many processes, including the cell division cycle. It seems that disruption of the temporal regulation could contribute to...
|
guest ::
