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Circadian system as a modulator of neuroinflammation
Kotková, Eliška ; Spišská, Veronika (advisor) ; Dočkal, Tereza (referee)
The circadian system is involved in the regulation of biological rhythms in physiological, behavioural and immune processes. These rhythms can be found in the central nervous system, including the blood-brain barrier, astrocytes, microglia, and the pineal gland, which produces the hormone melatonin. Neuroinflammation is a complex response of the central nervous system to inflammatory stimuli by rhythmic expression of pro-inflammatory and anti-inflammatory mediators or by rhythmic regulation of immune system cells. Studies have examined the influence of genes and proteins of the circadian system, suprachiasmatic nuclei, melatonin, and glial cell rhythms on neuroinflammation. Lipopolysaccharide was used to induce neuroinflammation in these studies. Based on these studies, the effect of melatonin on mikroglia and endothelial cells, and the responses of suprachiasmatic nuclei was evaluted as the most important circadian modulator of neuroinflammation. This thesis describes the basic principles of the circadian system and neuroinflammation, with the last section presenting the modulation of neuroinflammation by the circadian system. Keywords: astrocytes, blood-brain barrier, circadian system, cytokines, immune system, melatonin, microglia, neuroinflammation, suprachiasmatic nuclei
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Assessment of the influence of artificial lighting simulating a natural photoperiod and spectrum on the parameters of circadian rhythms of healthy volunteers
Gesztesová, Kristina ; Bendová, Zdeňka (advisor) ; Jelínková, Dana (referee)
The alternation of light and darkness on planet Earth has led to the development of endogenous systems that operate with a period of roughly 24 hours. We refer to these systems as circadian. For optimal functioning of the human circadian system, regular synchronization by an external stimulus is required. Light is a strong stimulus for synchronization for humans, but it should be noted that the outcome of this light synchronization depends critically on a number of factors. These factors include the timing and duration of the light pulse, as well as light parameters like spectrum and intensity. Commonly used interior lighting is often not optimal for the human endogenous circadian system, which is why the alternative of so-called biodynamic lighting (lighting that adequately stimulates the human organism) is being used more lately. As part of the experiment, we verified the effect of the newly created biodynamic lighting on the parameters of the circadian rhythm of healthy volunteers. Using methods of melatonin profile analysis, analysis of temperature records and actigraphy, we confirmed the influence of our experimental lighting.
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Effect of lighting conditions on fine hand motor skills in sleep deprived soldiers
Szewieczek, Jakub ; Maleček, Jan (advisor) ; Michalička, Vladimír (referee)
Title: Effect of lighting conditions on fine hand motor skills in sleep deprived soldiers Objectives: Determination of the effect of sleep deprivation performed during blue light exposure and during blue light blocking on fine motor skills of the hands. Methods: This theoretical-empirical work was conducted on a research cohort of 8 young men (n = 8) with an average age of 22,6 ± 1.6 years, height of 181,1 ± 3,7 cm and weight of 76,9 ± 4,9 kg. The participants were volunteers from the Military Physical Education Department at the Faculty of Physical Education and Sport (FPE) of Charles University (UK). The participants were induced into total sleep deprivation for 36 hours in two interventions. During this time, they followed established rules to avoid bias in the results and the course of the intervention was conducted according to standardized conditions. The first sleep deprivation intervention was performed in light and the second in darkness with blue light blocking. Disassembly and machine gun collection took place at fixed times and conditions, always at 7:30 am and 7:30 pm. Before each measurement, probands completed the Epworth Sleepiness Scale (ESS) questionnaire, which monitored the subjective level of sleepiness. In total, four measurements were taken with sleep deprivation and one...
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Regular physical activity as a circadian Zeitgeber
Fenclová, Aneta ; Bendová, Zdeňka (advisor) ; Červená, Kateřina (referee)
The function of almost every cell in the body is regulated by the circadian system. At the whole-body level, this system consists of the main oscillator, which is formed by the suprachiasmatic nucleus of the hypothalamus, and peripheral oscillators of individual organs and tissues. This system is sensitive to periodic changes in the external environment, particularly to the alternation of light and darkness, and under unfavorable lighting conditions, it can lead to desynchronization of both this timing system with the solar cycle and the mutual desynchronization of individual organs and tissues. This temporal mismatch of physiological processes can cause a range of diseases and metabolic disorders, and can be partially prevented by regular physical activity. Daily oscillations of circadian rhythms in many cardiovascular and metabolic parameters also determine the ideal time of day for anaerobic performance. This bachelor's thesis is a selection and comparison of information from professional literature and available studies dealing with the mutual influence of physical activity and circadian rhythms. There are works mentioned here that test the effect of physical activity on internal desynchronization of the melatonin rhythm and sleep pattern, on the circadian synchronization of skeletal muscle, as...
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The Importance of Circadian Rhythms in Humans with a Focus on Adolescents
Kolářová, Michaela ; Vančata, Václav (advisor) ; Ehler, Edvard (referee)
The aim of the presented diploma thesis is a detailed outline of the meaning of circadian rhythms in adolescence. Circadian rhythms appear in early childhood, but undergo many changes during lifetime. While in early childhood the waking and sleeping cycle shifts to an earlier time, during adolescence it is quite the opposite and the cycle is shifted a few hours later and in older age the cycle even returns to an earlier state. Adolescence is associated with the most significant changes and increased demands on study, independence and generally more overload at the expense of quality and adeqaute sleep, which not only causes circadian rhythms to dissipate and shift dramatically, which such as health. For adolescents, the delayed phase is naturally correlated with sexual development, with sleep patterns being controlled by the biological component. Respecting physiological changes in adolescence and striving for institutional changes seem to be the most appropriate therapies instead of forcing patterns basen on institutional and parental needs, which only undermines adolescent body chemistry, results in insufficient and poor quality sleep for functioning and healthy physiological development of adolescents.
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Blue light-blocking glasses and their effect on sleep quality parameters
Honzíková, Anna ; Levínská, Kateřina (advisor) ; Kolář, Jáchym (referee)
This study focused on sleep and the influence of blue light on sleep quality parameters. The experiment has been set up into a four-week research divided into two phases. Both phases were two weeks long. The first phase was without blue light blocking glasses, and the second phase with the glasses. We also worked with a Garmin smartwatch, sleep diary and standardized Pittsburgh Sleep Index questionnaire (filled out before and after the experiment). Parameters have been collected from a smartwatch (average heart rate, duration of sleep, duration of REM and NREM sleep, time of falling asleep, number of awakenings per night and stress levels), sleep diary (body temperature during night/morning, subjective quality of sleep and tiredness during the) and the Pittsburgh questionnaire. During the phase with glasses, probands had to wear them at least 90 minutes before sleeping. They could take them off only in a room without any artificial light. Every day probands filled up their sleep diary and entered information from their smartwatch. After the experiment, the data from both phases were processed and compared. Statistically significant parameters (p ≤ 0.05) were average heart rate, body temperature measured in the morning, number of awakenings per night, subjective sleep quality, results of a...
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Examination of circadian rhythm and light hygiene with focus on shift workers
TESKA, Andrej
The aim of this bachelor thesis was to summarize the existing knowledge about circadian rhythm, sleep, the role and importance of melatonin in the human body, the causes and consequences of circadian rhythm disruption and the possibilities of its strengthening for the best health and vitality. The thesis is designed as a literature search and is based mainly on foreign studies in this field, however, a lot of information is supplemented by Czech authors. Health in the 21st century is an absolutely complex value, which should also be looked at comprehensively. All possible aspects of the erosion of health, which are often overlooked, should be examined. The themes developed in this paper focus on the growing awareness that we ignore the circadian and sleep systems at our peril. It is the disruption of the circadian rhythm that, according to many studies, brings about health ailments in our time. Indeed, a large number of studies confirm that it is the breakdown of circadian rhythms that is behind many of the diseases that manifest in the modern world. This paper summarizes both the mechanisms of circadian rhythm functioning and its major disruptors and potential risk factors associated with various types of diseases. It provides new insights into how to care for our health in a holistic way that is as sustainable as possible.
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The Importance of Circadian Rhythms in Humans with a Focus on Adolescents
Kolářová, Michaela ; Vančata, Václav (advisor) ; Ehler, Edvard (referee)
The aim of the presented diploma thesis is a detailed outline of the meaning of circadian rhythms in adolescence. Circadian rhythms appear in early childhood, but undergo many changes during lifetime. While in early childhood the waking and sleeping cycle shifts to an earlier time, during adolescence it is quite the opposite and the cycle is shifted a few hours later and in older age the cycle even returns to an earlier state. Adolescence is associated with the most significant changes and increased demands on study, independence and generally more overload at the expense of quality and adeqaute sleep, which not only causes circadian rhythms to dissipate and shift dramatically, which such as health. For adolescents, the delayed phase is naturally correlated with sexual development, with sleep patterns being controlled by the biological component. Respecting physiological changes in adolescence and striving for institutional changes seem to be the most appropriate therapies instead of forcing patterns basen on institutional and parental needs, which only undermines adolescent body chemistry, results in insufficient and poor quality sleep for functioning and healthy physiological development of adolescents.
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The effect of melatonin on rhythmic ATP release from organotypic cultures of the rat SCN
Dvořáková, Barbora ; Svobodová, Irena (advisor) ; Jelínková, Dana (referee)
The rhythm of ATP accumulation is an one of examples of circadian rhythmicity which is demonstrated across the animal kingdom. It is located in the suprachiasmatic nucleus of hypothalamus, which is a centre of circadian clock and imposes rhytmicity on a whole organism. The question concering the ATP rhythm in an organotypic culture and the impact of melatonin on it has been discussing in this thesis. The synthesis of melatonin is regulated by the activity of the SCN and the hormon itself is known for its feedback on the SCN and a capability of regulating it. It has been shown that ATP rhythm is significantly inhibited under the constant control of melatonin and this inhibition is dose-dependent on a scale of 0,1-10 nM. In case of one-time applied melatonin in 4 p.m. there is no reduction in the accumulation of extracellular ATP but there is a phase shift in ATP rhythm. It has also been shown that ATP rhythm is inhibited and desynchronized under the control of tetrodotoxin which blocks an electric activity of neurons. These results show that melatonin is capable of inducing phase delay of ATP rhythm in SCN and reducing an amount of extracellular ATP, that the effect of melatonin is probably mediated by specific receptors and lastly that ATP rhythm is a result of cell-cell interaction between neurons...
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