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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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Research into the mechanisms of methamphetamine dependence
Havlíčková, Tereza ; Šustková, Magdaléna (advisor) ; Šlamberová, Romana (referee) ; Petrásek, Tomáš (referee)
The presented dissertation deals with the issue of methamphetamine dependence. The first part focuses on a research that seeks a new promising possibilities of using ghrelin antagonist to reduce the potentiating effects of methamphetamine, with the intent of a more effective approach/treatment in current unsatisfactory approach in methamphetamine dependence. Furthermore, it summarizes the already available knowledge that deals with the possibilities of influencing the mechanisms of substance abuse through ghrelin antagonism, and especially focuses on our own experimental work. We tested the efficacy of the GHS- R1A receptor antagonist, JMV2959, in experimental models of methamphetamine dependence. There is only a minimum of work dealing with this issue yet. The experimental part summarizes the results of our two studies examining the effect of a ghrelin antagonist on the development of addictive reinforcing mechanisms, methamphetamine intake itself and the tendency to relapse behavior. Using the drug conditioned place preference (CPP) method in rats, we demonstrated in two experimental settings a significant effect of ghrelin antagonism on the development of methamphetamine binding to the environment and on the already induced search for a drug-related environment. We have shown that a GHS-R1A...
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Learning and memory in Nogo-A knockdown rats
Petrásek, Tomáš
The Nogo-A protein belongs among the most important regulatory molecules in the brain, regulating development of neuronal and glial cells, axon guidance and adult synaptic plasticity. Although it has been studied mainly as an obstacle to axon regeneration after CNS injury, it plays a role in many pathological conditions, including neurodegenerative and neuropsychiatric diseases. This work offers a literature review of the current knowledge about functions of Nogo-A and related proteins, and then recapitulates the results of experiments focused on the impact on decreased expression of Nogo-A on behavior in a transgenic rat model. The most important finding is that the Carousel Maze performance, tapping higher cognitive functions such as cognitive coordination and cognitive flexibility, is remarkably impaired in this model, while other cognitive functions, such as spatial navigation and both spatial and non-spatial memory are spared in the Nogo-A deficient rats. The results are discussed in the context of a hypothesis linking Nogo-A mutations or abnormal expression to human schizophrenia. We conclude that the Nogo-A deficient rats constitute a very promising animal model of schizophrenia and deserve further attention.
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Learning and memory in Nogo-A knockdown rats
Petrásek, Tomáš ; Stuchlík, Aleš (advisor) ; Zach, Petr (referee) ; Rokyta, Richard (referee)
The Nogo-A protein belongs among the most important regulatory molecules in the brain, regulating development of neuronal and glial cells, axon guidance and adult synaptic plasticity. Although it has been studied mainly as an obstacle to axon regeneration after CNS injury, it plays a role in many pathological conditions, including neurodegenerative and neuropsychiatric diseases. This work offers a literature review of the current knowledge about functions of Nogo-A and related proteins, and then recapitulates the results of experiments focused on the impact on decreased expression of Nogo-A on behavior in a transgenic rat model. The most important finding is that the Carousel Maze performance, tapping higher cognitive functions such as cognitive coordination and cognitive flexibility, is remarkably impaired in this model, while other cognitive functions, such as spatial navigation and both spatial and non-spatial memory are spared in the Nogo-A deficient rats. The results are discussed in the context of a hypothesis linking Nogo-A mutations or abnormal expression to human schizophrenia. We conclude that the Nogo-A deficient rats constitute a very promising animal model of schizophrenia and deserve further attention. Powered by TCPDF (www.tcpdf.org)
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Ontogenesis of episodic memory in preschool children
Píšová, Martina ; Nekovářová, Tereza (advisor) ; Petrásek, Tomáš (referee)
Episodic memory enables us to remember and recall life events from the past. Episodic memory is a specific type of long-term declarative memory, which undergoes changes in ontogeny. To examinate of episodic memory, "episodic-like memory model", was developed. This model focuses on three basic components of episodic memory: "What happened", "Where did it happen" and "When did it happen". The aim of this diploma thesis is to develop and to validate of particular tests of episodic memory with consideration for their feasibility for preschool children. In order to study episodic memory we used an "episodic-like memory model" and experiments which focused on: children's verbal ability, differentiation of two perspectives during remembering of events and timing memories on an autobiographical axis. We aimed to inspect the effect of age on performance in these tests, possible links between performance in these experiments and the effect of level and the three components of episodic memory on number of errors made. In our dataset we found a significant effect of the age of children in Sentence repetition test and in test of Object collection in the virtual house, in the same test we found a effect of the level on number of errors. We also found a significant correlation between correct responses in verbal...
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Social behavior and communication in a laboratory rat and autism models
Tučková, Klára ; Petrásek, Tomáš (advisor) ; Pohanová, Petra (referee)
Social behavior of the brown rat as an animal living in a hierarchical collonies is very diverse and developed, which remains the same with the domestic laboratory rat. Rats communicate not only via odors, but also via various types of vocalizations, which express stress, pain or anxiety or on the other hand positive emotions and also communication during any social contact. Because of complex social behaviour and communication, rat is a suitable model organism for research of human mental disorders such as autism. This thesis gives an overview of natural social behaviour of rats, behavioural methods used for testing of animal models and describes selected rat models of autism induced through various types of interference (natural mutation, gene inactivation, virus infection and chemical disruption of brain development) and compares their impact at the level of rat behaviour. Key words Rat, social behaviour, communication, vocalization, experimantal tasks, model organism, autism, models of autism
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Relative numerosity discrimination in primates
Moravcová, Anna ; Nekovářová, Tereza (advisor) ; Petrásek, Tomáš (referee)
This work is focused on numerical competence in primates specifically focusing on relative numerosity, one of the many aspects of these cognitive abilities. Relative numerosity is an ability to discriminate a larger quantity from a smaller amount or smaller quantity from a larger amount and could be classified as one of the easiest numerical competence. In this work I have summarized the present knowledge of numerical competences in primates, which have been so far studied only in a few species of primates, most of them was rhesus macaque (Macaca mulatta) and chimpanzee (Pan troglodytes). In the experimental part I focused on the research of relative numerosity in rhesus macaque (Macaca mulatta). The goal of my work was to find out whether macaques are able to solve the problem of relative abundance with different types of stimuli. Another goal was to find out whether they are able to generalize information about relative abundance and whether they can apply it for new design of the task. The results confirm that macaques possess the ability of relative numerosity and are able to abstract stimuli that are differing in their character. This proves that they are not learning to recognize a particular stimul, but are able to use this numerical skill on any type of stimul. I also found out that...
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Possible perspective use of ghrelin mechanisms in the treatment of opioid addiction
Jeřábek, Pavel ; Šustková, Magdaléna (advisor) ; Šlamberová, Romana (referee) ; Petrásek, Tomáš (referee)
This dissertation deals with the narrow issue of the new perspective research direction, which is research of the possibility of using ghrelin antagonism in the treatment of opioid addiction, which has been rarely studied yet. It summarizes the general principles of neurobiological mechanisms of drug addiction as well as treatment guidelines and procedures based on these findings. The definition of addiction as a disease together with the factors contributing to its formation and course, are presented in this dissertation. The definition includes individual repetitive phases (cycles) of the substance addiction, along with a description of the anticipated involvement of individual brain structures and basic neuromediators involved in these phases, including references to the most important literary findings on the role of ghrelin in the mechanisms of addiction, focused on mechanism of action of ghrelin in the opioid addiction. In the experimental part, the results of the CNS microdialysis experiments in rats, using the GHS-R1A antagonist (JMV2959 pretreatment), were presented in both acute single dose morphine experiment and sub-chronic experiment in which morphine was administered in increasing doses for five consecutive days. The results are presented in relation to changes in the level of...
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The effect of stress in early ontogeny on behavioural characteristics of rodents
Chumová, Petra ; Landová, Eva (advisor) ; Petrásek, Tomáš (referee)
Postnatal stress and sensory stimulation are major factors causing the acute changes in development of neuroendocrine system that can influence the expression of behavioural phenotype in adult rodents. Variability of early life environment and stress affect the development of individual through the changes of maternal care. The amount and quality of maternal care influence the function of HPA axis and stress hormone levels in pups during the hyporesponsive period, which provides them lesser vulnerability against the potential impact of stressors. This mechanism is crucial for physiological development of hippocampus, amygdale and prefrontal cortex, the brain regions that are highly important for regulation of adult behaviour. The absence of maternal care and social contact in postnatal and early weaning ontogeny are possibly the biggest stressors in rodents. While neonatal handling (brief maternal separation) has mainly positive effects on the development of emotional and cognitive abilities, prolonged and repeated maternal separation and early weaning result in stress-response alterations and long-lasting impairments in many behavioural traits mediated by the lack of maternal care. This thesis summarizes current knowledge of endocrinological and behavioural consequences of early postnatal stress...
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