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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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Circadian system in adolescents and the use of light therapy
Kučerová, Jana ; Červená, Kateřina (advisor) ; Pačesová, Dominika (referee)
Circadian rhythms, as regularly recurring events in living organisms with a period of approximately 24 hours, are an important part of life on Earth. To keep the period of the internal circadian clock of an organism in line with the cycle of the Earth Day, synchronization of this clock is necessary. The most important factor in synchronizing the circadian clock is light, which provides the brain with information about the phase of the Earth Day. The individual setting of the circadian clock, which is manifested in the form of a chronotype, has a profound effect on the life of the individual. Chronotypes change throughout life, and the most significant changes occur during adolescence, when the overall chronotype shifts. This results in adolescents going to bed later even though they have to get up early for school. This is also why they are more likely to suffer from sleep deprivation, be inattentive at school or fall asleep during lessons. Consequently, they experience, often with significant, social jet lag, which is a health risk. Light therapy offers a solution. This paper presents its general use, as well as specific examples of its use with delayed adolescents. However, there are also other ways to improve the situation of adolescents, e.g., delaying the start time of school in the morning,...
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Genetic factors in the etiology of sleep disorders
Dvořáková, Markéta ; Šolc, Roman (advisor) ; Červená, Kateřina (referee)
Sleep disorders are a group of disorders affecting a considerable part of proportion of the human population. Their aetiology is usually very complex and includes environmental and genetic factors. The nature of these disorders is often multifactorial. Sleep medicine and the field of synthesis of its findings with those of modern or classical genetics still offer quite a huge possibilities of research. However, despite many unresponsed questions, it is now possible to summarise the identified confirmed or suspected genes whose mutations are involved in the causes of these disorders. It is possible to estimate the heritability of certain disorders based on their multiple occurrence in families, presence in twins or prevalence in the population across different ethnics. This bachelor thesis focuses on genetic aspects in the etiology of sleep disorders, their heritability, the strength of the genetic component, and genetic links between some of the disorders.
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Physical and mental performance of morning and evening chronotypes in different times of day
Červená, Kateřina ; Bendová, Zdeňka (advisor) ; Jelínková, Dana (referee) ; Větrovský, Tomáš (referee)
Circadian rhythmicity, which evolved in accordance with the rhythmicity of the external environment tied to the earth's rotation, governs the regular rhythms of our physiology and behavior. The central circadian clock in the suprachiasmatic nuclei of the hypothalamus controls the roughly 24-hour rhythmicity of many peripheral clocks of most cells of the body, that can be observed from the molecular to the behavioral level. The intrinsic circadian period (τ) in humans is on average slightly longer than 24 h, but may also be slightly shorter. Individuals with a short τ are referred to as morning chronotypes, whereas individuals with a long τ are referred to as evening chronotypes. However, the majority of the population belongs to the so-called intermediate chronotype. The molecular mechanism of circadian oscillations controlled by the circadian clock has been shown to be closely linked to cellular metabolism. Many physiological processes important for physical and cognitive performance are also regulated by the circadian system. The main aim of both studies was to quantify the difference in performance during morning and evening testing in subjects of a pronounced evening and morning chronotype. While the motivation for conducting Study A was practical, with the aim of identifying potential biases...
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Incidence and role of the purinergic P2X7 receptor in the immune system
Piskačová, Kateřina ; Zemková, Hana (advisor) ; Červená, Kateřina (referee)
It has been shown recently that extracellular ATP and its metabolite adenosine are key mediators in the immune system. Depending on the concentration, ATP may act as an activator or an inhibitor to the immune response, whereas adenosine is generally well known as a specific immunosupressor. Signals delivered by extracellular ATP and adenosine are detected and transduced by purinergic P2- and P1- receptors, respectively. In principle, all cells of the immune system express P2X, P2Y and adenosine P1 receptors on their plasmatic membrane. Therefore, the purinergic signaling extends to all components of the immune and inflammatory responses, including neurodegenerative diseases. This knowledge triggered a wave of interest in research, development and synthesis of new compounds having effect on P1- and P2- receptors that could help in the treatment of chronic inflammatory diseases and neurodegenerative diseases. This bachelor thesis will summarize the most recent knowledge on the role of the P2X7 receptor in these processes. This subtype of P2-receptor is unique because it is involved in the release of cytokines from immune cells and plays a role in the cell growth and apoptosis.
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Expression of AMPA glutamate receptor subunits in the suprachiasmatic nucleus of the rat
Červená, Kateřina ; Bendová, Zdeňka (advisor) ; Zemková, Hana (referee)
The main mammalian circadian pacemaker stored in suprachiasmatic nuclei of the hypothalamus (SCN) is adapted to changes in the external environement by synchronization of its endogenous period with periodic changes of light and dark during day and night. The information about light travels via glutamatergic retinohypothalamic tract to the ventrolateral part of the SCN. Activation of ionotropic glutamate receptors in this area provably mediates the transfer of information about light on the transcriptional mechanism of light-sensitive cells. The role of the NMDA type of ionotropic glutamate receptors is well studied in this field and it is known that some NMDA receptor subunits show a circadian rhythm and an increased expression after a light pulse. Signalization via AMPA type receptors is much less elucidated. The aim of this thesis was to determine which AMPA receptor subunits are expressed in the SCN of the rat and if these subunits show a daily rhythm of expression and a reactivity to light pulse, as well as to outline the possible roles of distinct AMPA receptor subunits in the SCN. Keywords: circadian rhythms, suprachiasmatic nuclei, glutamate receptors, AMPA
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Role of glutamatergic transmission in mechanisms of addiction to morphine.
Moutelíková, Karolína ; Hejnová, Lucie (advisor) ; Červená, Kateřina (referee)
Drugs are used by mankind since ancient times. One group of these substances are opioids. Opioids have antinociceptive effects and can induce euphoria and relaxation as well. A chronic usage of opioids can lead to a development of drug addiction and phenomens like tolerance and sensitization. One of the most used opioids in medicine is morphine. Morphine is isolated from opium of poppy (Papaver somniferum). Direct effect of morphine is mediated via activation of μ- opioid receptors and their signal cascade. It was implicated that the usage of morphine affects other neurotransmmiter systems in the brain and these neurotransmmiter systems play a signifikant role in the development of addiction and other phenomena. One of these systems is an important excitatory brain system - glutamergic system. This bacherol thesis focuses on interrelationship between opioid and glutamatergic systems during addiction.There were described changes in a composition of glutame ionotropic receptors and changes in their expression as well as in expression of metabotropic glutamate receptors. These changes differ in various parts of the brain and in diverse stages of addiction on morphine too. In spite of all diferences, the results of studies indicate that glutamatergic receptors play a significant role in the development...
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Impact of circadian system disruption on development of gastrointestinal disorders
Kubištová, Aneta ; Sumová, Alena (advisor) ; Červená, Kateřina (referee)
The ability to sense 24-hour cycles in external environment and to adapt to them is present in a great array of species living on the Earth. Mammals possess internal time-keeping system which is composed of circadian clocks located in the suprachiasmatic nuclei (SCN) of the hypotalamus and peripheral clocks in various tissues and organs of the body. These clocks are adapting to the changes of external environment, such as light and dark cycles or feeding cycles. Peripheral clocks in the organs of the digestive system are synchronized with the signals derived from the central clock in the SCN and also with signals from food intake. Discordance between these signals may result in development of various diseases of the gastrointestinal tract (GIT) related to insufficient digestion or even in higher risk of developing a cancer. This bachelor thesis is generally aimed at circadian rhythms in the body, with the focus on rhythms in the GIT. It will deal with the importance of the circadian rhythms for correct GIT functions. Furthermore, the thesis is focused on connection between the desynchonization of the circadian clock and GIT disease development, namely of obesity and cancer.
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Gut microbiota effect on neuropsychiatric diseases
Pospíšil, Vít ; Kostovčíková, Klára (advisor) ; Červená, Kateřina (referee)
The intestinal microbiome is formed by trillions of microorganisms that accompany us throughout our lives. Commensal gut microorganisms, as a complex system, interfere with diet processing and subsequent spectrum of released metabolites, which are involved in communication with other systems of the human body. Recently, a link between intestinal microbiota dysbiosis and activation of the immune response has begun to emerge. This pathophysiological condition is associated with the loosening of the tight junctions of the gut epithelial barrier, which could together with prolonged immune inflammation lead to what is known as irritable bowel syndrome. This disease is not only related to symptoms associated with bowel discomfort, but also to effects on afferent nerve endings. This connection has been called as the gut-brain axis and became the link between the gut microbiota and psychiatric diseases. This work is summing up the actual knowledge on this topic and offers a comprehensive overview of the subject from both an immunological and a microbiological point of view. Key words: gut-brain axis, depression, anxiety, antibiotics, antidepressants, probiotics, IBS
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