National Repository of Grey Literature 11 records found  1 - 10next  jump to record: Search took 0.00 seconds. 
New synthetic drugs and the mechanisms underlying their effects
Kozová, Johana ; Novotný, Jiří (advisor) ; Petrásek, Tomáš (referee)
New synthetic drugs are a large group of addictive substances currently synthesized for the purpose of circumventing legislation. Most often, they are created by a relatively slight change of the structure of previously banned substances. Any drugs and their long-term use have a detrimental effect on the life of the individual and society as a whole. Therefore, understanding the mechanism of their action is important for the treatment of complications caused by them and may also serve to develop drugs for treatment of certain diseases. This bachelor thesis deals with the current knowledge about the mechanism of action of new synthetic drugs - synthetic cathinones, especially mephedrone, methylone and MDPV. In the paper, the mechanism of action of amphetamine is also presented for comparison. Keywords: drugs, synthetic cathinones, mephedrone, methylone, MDPV
Mirror neuron system: Mechanisms and functions
Loginova, Alisa ; Nekovářová, Tereza (advisor) ; Petrásek, Tomáš (referee)
Mirror neurons (MN) are a group of neurons with extraordinary visuomotor character. Their activation is connected to an observation of a certain action and its execution, if the action was already in motoric repertoire of the observer. MN were firstly identified in macaque's brain, with later identification in human's brain. The most important structures where we can find the MN are Broca's area located in the inferior part of frontal gyrus (IFG), premotor cortex and superior parietal lobule (SPL). The functions of MN are various, they take part in action understanding, imitation, learning and language. According to present knowledge, they were assigned a role in social cognition - while experiencing empathy and theory of mind (ToM). Empathy can be defined as sharing of another person's emotions. ToM highlights the importance of one's ability to represent metal states of other people, knowledge, wishes and experiences. It leads towards understanding and anticipating of another person's actions. Additionally to MN, amygdala, insula and basal ganglia are also important in processes of social cognition. Impairments of social cognitive skills are in autism, schizophrenia and psychopathy. Key words: mirror neuron system, motor area, social cognition, empathy, theory of mind
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.
Separation of hippocampal function in Morris water maze and in active place avoidance by alternance protocol
Vojtěchová, Iveta ; Petrásek, Tomáš (advisor) ; Hiadlovská, Zuzana (referee)
In this work, we examined the executive functions of the hippocampus at the behavioral level as a so-called behavioral separation in adult rats. We studied an impact of day-to-day alternation versus sequential learning (and the order of learning) of two spatial tasks (Morris Water Maze and Active Allothetic Place Avoidance) testing different hippocampal functions (experiment 1), or an impact of sequential versus alternating learning of one task (Active Allothetic Place Avoidance) in two different rooms (experiment 2), on performance. We found out that rats are able to learn both tasks as well as to discriminate between the two contexts regardless of the order or alternating of learning. Because such executive functions are impaired in human patients suffering from schizophrenia, we used this procedure also in the rat model of schizophrenia induced by acute intraperitoneal application of dizocilpine (MK-801), glutamate NMDA receptors antagonist, in the dose of 0.08 mg/kg. We failed to selectively disrupt the behavioral separation, however, we observed general learning deficit and hyperlocomotion regardless of the alternation in the Active Allothetic Place Avoidance task in these rats. The cognitive impairments in connection with learning after such low dose of MK-801 in this task have not yet been...
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)
Referential vocalization of primates
Rejlová, Markéta ; Nekovářová, Tereza (advisor) ; Petrásek, Tomáš (referee)
Some types of vocalization encode only the individual properties of vocalization individuals such as species, size, and its motivational state, but also inform about events and objects around. This vocalization is called "functional reference." Referential communication acoustically different from other kinds of vocalization, and is produced only in response to specific stimulus. Recipient responds to vocalizations indirect information in the same manner as if the present initiative. Aim of this work to summarize the current knowledge on the referential communication of primates, especially food and anti-predator type, including neurological mechanisms, gestures intermediate, referential signal and interspecies comparisons. Keywords: referential communication, vocalization, primates, anti-predator behavior, feeding behavior
Inhibitors of axonal regeneration and their importance for neuroplasticity, behaviour and memory
Vojtěchová, Iveta ; Petrásek, Tomáš (advisor) ; Hock, Miroslav (referee)
The central nervous system of higher vertebrates, in contrast to the peripheral one, doesn't regenerate. That is because of the presence of many growth inhibitors produced by a glial scar and oligodendrocytes; the most important inhibitors are MAG (myelin-associated glycoprotein), OMgp (oligodendrocyte-myelin glycoprotein) and mainly Nogo protein. Nogo-A is one of three isoforms of the Nogo protein located primarily in the brain and the spinal cord where it causes the degradation of growth cones, inhibits the growth of neurites, restricts the neuroplasticity and prevents the regeneration of injured axons in adulthood. The Nogo receptor complex serves for a reception of signals and the following signal cascade causes the destabilisation of actin filaments. There are also other receptors for Nogo-A, e. g. the PirB receptor. During the development, Nogo-A is highly expressed by neurons but in adulthood, the main producers are oligodendrocytes. It is noteworthy, that neuronal expression of Nogo-A doesn't decrease after birth in structures with high plasticity, e. g. in the hippocampus which is important especially for spatial learning and memory. In the hippocampus, Nogo-A keeps a balance between the synaptic plasticity and stability and restricts the long-term potentiation. Therefore, this bachelor's thesis...
The effect of antagonism of adrenergic receptors on spatial learning in laboratory rats.
Petrásek, Tomáš ; Otáhal, Jakub (referee) ; Stuchlík, Aleš (advisor)
Spatial navigation is an important aspect of animal behavior, and is often regarded as a model of higher cognitive functions, e.g. declarative memory. It can be easily assessed by various behavioral tasks ("mazes"), and compared even across different species. Therefore, spatial tasks are especially suitable for evaluating potential psychoactive drugs in an animal model. This work deals mainly with noradrenergic neurotransmitter system and its influence on learning, memory and spatial behavior. The experimental part focuses on effects of subtype-specific noradrenergic antagonists prazosin, idazoxan and propranolol, and also a D2 dopaminergic antagonist, sulpiride, in Active Allothetic Place Avoidance (AAPA) task, a novel spatial task, well suited for measuring both cognitive and motor impairments. Rats with high doses of noradrenergic antagonists show combined impairment in both cognitive and motor aspect of the task. β-adrenergic antagonist propranolol also causes specific cognitive impairment in a lower dose of 25 mg/kg, but it fails to induce long-term memory impairment when given after experimental session. Co-application of alpha-1 adrenergic and D2 dopaminergic antagonists, prazosin and sulpiride, causes a severe motor and cognitive impairment, even at doses that do not influence animal behavior when...
Farms for rearing pigs in terms of noise level in the neighborhood.
PETRÁŠEK, Tomáš
The bachelor thesis is aimed at assessing the farm for rearing pigs in terms of noise level in the neighborhood. The main objective was to measure the noise during the working operation at different places of the selected object, to process the collected data, to calculate the equivalent noise level and then evaluate the results of the work. On the basis of measured and assessed values is apparent that the noise pollution of the examined object has no effect on its neighborhood and therefore it is not necessary to propose any specific actions to improve the current situation.

National Repository of Grey Literature : 11 records found   1 - 10next  jump to record:
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5 PETRÁŠEK, Tomáš
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