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Synchronization of circadian clock in hippocampus
Kubátová, Eliška ; Sumová, Alena (advisor) ; Liška, Karolína (referee)
Circadian rhythms refer to the physiological, biochemical and behavioral changes of the organism with a period of about 24 hours, such as the cycle of sleep and wakefulness, the release of hormones, enzymatic activity or gene expression. Apart from the central pacemaker located in the suprachiasmatic nucleus (SCN) of the hypothalamus, we find many other peripheral oscillators in which we observe the rhythmic expression of clock genes. In this study, we focused on one of the peripheral brain oscillators located in the hippocampus. The hippocampus is best known for its role in memory formation through the mechanism of long- term potentiation (LTP). The formation of LTP is another process that exhibits circadian variation. Although the rhythmic expression of genes in the hippocampus has already been demonstrated, the mechanisms of synchronization of these clocks remain a subject of investigation. In this study, we studied the effect of candidate substances - N-methyl-D- aspartate (NMDA) and leptin on the circadian clock of the hippocampus. Genetically modified mPer2Luc mice were used as a model. The main goal of the work was to introduce a method of preparing organotypic explants of the hippocampus of these mice for monitoring the circadian clock in real time using the LumiCycle device. Next goal was...
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Circadian clock in the hippocampus
Liška, Karolína ; Sumová, Alena (advisor) ; Riljak, Vladimír (referee) ; Ježek, Karel (referee)
To adapt to the daily changing environment, living organisms on Earth have developed an inner clock. In mammals, the clocks are organized in a circadian system which is governed by the central oscillator in suprachiasmatic nuclei (SCN) and consists of peripheral oscillators located in tissues and organs throughout the body. The synchrony of the entire system allows proper alignment of physiological processes to the optimal time of day. It was shown that cognitive performance and memory formation are also subjected to daily variations and many brain regions involved in these processes, especially hippocampus (HPC), were recently found to harbor circadian clocks. Nevertheless, the precise function of these clocks and the mechanism of their synchronization to the external conditions remain to be elucidated. The focus of my PhD thesis was a detailed analysis of the circadian clocks in rodent HPC. We aimed to characterize the oscillators in distinct HPC subregions, identify signals responsible for their synchronization and compare the HPC clock properties to those of the clock in the choroid plexus (CP) which is the adjacent non-neuronal structure. Moreover, we examined the role of clocks in HPC and other brain regions in the process of memory formation, focusing on time memory acquisition. First, we...
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