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Synchronization of circadian clock in rat during ontogenesis and in adulthood
Olejníková, Lucie ; Sumová, Alena (advisor) ; Šlamberová, Romana (referee) ; Mareš, Jan (referee)
The circadian system temporally controls behavioral and physiological processes in most organisms so that they change during the day and night with a period of about 24 h. It is an evolutionary adaptation to anticipate periodic changes in environment on the Earth. In mammals, the circadian system consists of the central pacemaker in the suprachiasmatic nuclei (SCN) of hypothalamus and of oscillators located in numerous peripheral organs and tissues. At the molecular level, the circadian clock is based on the rhythmic expression of so called clock genes. The ontogenetic development of the circadian system is a gradual process and the most important changes undergo during the late embryonic and early postnatal stage. Many behavioral, hormonal and metabolic signals provided by the mother are considered to be involved in circadian clock synchronization during early ontogenesis. The mechanisms of the entrainment are not fully known yet. The aim of this thesis was to study the development of the circadian clock and its entrainment via maternal signals and to compare the development of circadian rhythms in two model rat strains - Wistar rat and spontaneously hypertensive rat (SHR). Firstly, we described the ontogenetic maturation of the Wistar rat circadian clock in the colon from the fetal stage until...
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The effect of psilocybin on memory consolidation in rats
Chona, Kembe ; Olejníková, Lucie (advisor) ; Petrásek, Tomáš (referee)
Psychedelics are currently being researched due to their long-lasting antidepressant, anxiolytic and neuroplasticity inducing actions. The mechanism by which they induce these effects remains poorly understood. Here, we decided to investigate a relatively unexplored possibility. A potential interaction of psilocybin administration and sleep and their combined effects on memory consolidation. Memory formation in animals and humans is greatly influenced by sleep manipulation which led us to assess the possibility with spatial memory tasks. We hypothesized that acute psilocybin administration after learning may have a beneficial influence on memory consolidation in rats. To determine whether an interaction with sleep exists we also subjected the rats to combinations of psilocybin and control vehicle with normal sleep and sleep deprivation. Our data did not suggest such an interaction exists. Secondly, we tried to find out if psilocybin and sleep manipulation leads to changes in neuroplasticity-related events. A process that could very likely be the basis of such a proposed beneficial effect. For this purpose, we analysed the expression of the immediate-early gene Arc and the immature neuron marker doublecortin in the rat hippocampus. Doublecortin's expression was not influenced by any of the factors....
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Cerebral organoids as a neurodevelopmental model of schizophrenia
Sovíčková, Lucie ; Weissová, Kamila (advisor) ; Olejníková, Lucie (referee)
The neurodevelopmental model of schizophrenia incorporates genetic and environmental factors, which both play a role in the development of this disorder. For example the risk of developing schizophrenia is increased by prenatal stress in a sex-dependant manner. Fibroblast growth factor receptor 1 plays a role in neurodevelopmental abnormalities and has been found to influence cortical development, development of dopaminergic neurons and genes dysregulated in schizophrenia. Circadian, hypothalamic-pituitary-adrenal axis and sleep abnormalities are also common in schizophrenia patients and they might increase susceptibility to psychosis via dopaminergic system. The schizophrenia susceptibility gene Disc1 has been found to play a role in sleep abnormalities and regulation of radial glia cell cycle. Cerebral organoids, which are generated by using human induced pluripotent stem cells, model human brain development and could be used for further studies of neurodevelopmental model of schizophrenia. Cerebral organoids could be improved in the future by vascularization and bioengineering methods. Key words: cerebral organoids, schizophrenia, circadian rhythms, stress, FGFR1, DISC1, glucocorticoids
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Synchronization of circadian clock in rat during ontogenesis and in adulthood
Olejníková, Lucie ; Sumová, Alena (advisor) ; Šlamberová, Romana (referee) ; Mareš, Jan (referee)
The circadian system temporally controls behavioral and physiological processes in most organisms so that they change during the day and night with a period of about 24 h. It is an evolutionary adaptation to anticipate periodic changes in environment on the Earth. In mammals, the circadian system consists of the central pacemaker in the suprachiasmatic nuclei (SCN) of hypothalamus and of oscillators located in numerous peripheral organs and tissues. At the molecular level, the circadian clock is based on the rhythmic expression of so called clock genes. The ontogenetic development of the circadian system is a gradual process and the most important changes undergo during the late embryonic and early postnatal stage. Many behavioral, hormonal and metabolic signals provided by the mother are considered to be involved in circadian clock synchronization during early ontogenesis. The mechanisms of the entrainment are not fully known yet. The aim of this thesis was to study the development of the circadian clock and its entrainment via maternal signals and to compare the development of circadian rhythms in two model rat strains - Wistar rat and spontaneously hypertensive rat (SHR). Firstly, we described the ontogenetic maturation of the Wistar rat circadian clock in the colon from the fetal stage until...
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Circadian system of laboratory rat during ontogenesis
Olejníková, Lucie ; Sumová, Alena (advisor) ; Mareš, Pavel (referee)
One of the attributes common to almost all living organisms is an ability to generate and maintain endogenous rhythms, which are driven by the biological clock. The rhythms, which recur under constant conditions with a period of about 24 hours, are known as the circadian rhythms. The circadian rhythms include e.g. rhythms in sleep/wake, locomotor activity, body temperature and hormonal secretion. In mammals, the circadian system consists of the central oscillator in the suprachiasmatic nuclei (SCN) of the hypothalamus and other oscillators that reside in various brain areas as well as in numerous peripheral organs and tissues. Ontogenetic development of the circadian system proceeds gradually. The circadian system undergoes the most dramatic changes during the late embryonic and early postnatal period. Under natural conditions, the circadian clocks are precisely entrained to the 24 hour period by regular changes of the light and dark cycle. Under conditions when the periodic light-dark rhythm is disrupted as well as during the early ontogenesis, other mechanisms can be involved in the entrainment of the central clock in the SCN. All mechanisms of the entrainment are not fully known yet, but they involve plenty of behavioral, hormonal and metabolic signals. The aim of this thesis was to study the entrainment...
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Circadian clock during ontogenesis
Olejníková, Lucie ; Sumová, Alena (advisor) ; Hock, Miroslav (referee)
Circadian system enables adaptation of organisms to periodic changes in environment on the Earth. In mammals, it consists of central pacemaker in the suprachiasmatic nuclei (SCN) of hypothalamus and of oscillators that reside in other brain areas as well as in the peripheral organs and tissues. Ontogenetic development of the circadian system is a gradual process and the most dramatic changes undergo during the late embryonic and early postnatal stage. For its proper function, not only the morphological development of its individual parts, but also development of their entrainment to external environment and among each other, is important. The oscillations in clock gene expressions in the SCN occur already before birth, but in view of the fact that the levels of their protein products are undetectable, at this developmental stage, the ability of SCN to generate these oscillations in vivo has been discussed. After birth, the levels of these proteins rise and the rhythms in clock genes expression achieve the adult-like level at the postnatal age, when the synaptogenesis in the SCN is completed. The presence of a functional maternal circadian system is not necessary for the endogenous development of the SCN clock in pups, because the maternal SCN only entrains the clock and the circadian oscillations thus...
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