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Possible influencing the motor performance of developing rats by repeated administration of the NMDA receptor antagonist specific for NR2 subunit
Kozlová, Lucie ; Mareš, Pavel (advisor) ; Valeš, Karel (referee)
Nonspecific NMDA receptor antagonists induce hyperlocomotion in rats. The aim of this work is to determine whether the NMDA receptor antagonist specific for NR2 subunit exhibit similar negative effect as nonspecific antagonists. This subunit is predominant in the brain in the early postnatal period. The introduction summarizes the data on NMDA receptors and the development of rat. The experimental part deals with the action of a specific NMDA receptor antagonist Ro 25-6981 on motor performance of developing rats. Substance was repeatedly administered to rats at postnatal days 7 to 11. Spontaneous locomotion and motor performance of the animals were repeatedly tested up to adulthood by battery of tests appropriate for individual ages. Our research demonstrated that this substance does not have significant effect on motor system of laboratory rat and that it might be further tested as a possible age-bound antiepileptic drug.
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The influence of the neuroactive steroids inhibiting NMDA receptors on behaviour
Chvojková, Markéta ; Valeš, Karel (advisor) ; Mareš, Pavel (referee)
The neuroactive steroid pregnanolone glutamate (Pg glu), a synthetic analogue of the naturally occurring pregnanolone sulfate (3alpha5betaS), has neuroprotective properties and a minimum of adverse effects. The subject of my thesis is the influence of selected structural modifications of the molecule Pg glu on biological effects. The first modification involves an increase of lipophilicity, the second involves the attachment of a positively charged group to C3. All these neuroactive steroids are use-dependent inhibitors of NMDA receptors. The first aim of this thesis was to determine the neuroprotective effectiveness of the neuroactive steroids chosen. The second aim was to explore the influence of selected neuroactive steroids on motor coordination, reflexes, anxiety and locomotor activity, as well as the effect of their high doses. The third aim was to create a battery of behavioural tests for screening the biological effects of analogues of Pg glu in laboratory rodents. The neuroprotective effects were evaluated in a model of excitotoxic damage of hippocampus in the rat on the basis of its behavioural consequences. The neuroprotective efficacy of androstane glutamate (And glu) and Pg glu was demonstrated. In the case of positively charged molecules, neuroprotective efficacy was not demonstrated....
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The role of aging and stress in autophagy
Čechová, Kateřina ; Vrajová, Monika (advisor) ; Valeš, Karel (referee)
Autophagy is a nonspecific catabolic mechanism, important for maintaining the cellular homeostasis. Stress condition can increase the activity and support the cell survival. It is well known that normal and pathological aging are associated with a reduced autophagic potential and that experimental induction of autophagy leads to higher longevity of certain model organisms. This decreasing may be facilitated by other factors, such as chronic stress. Higher age and chronic stress are two factors contributing to the development of neurodegenerative diseases, in this context the mechanism of autophagy is now actively studied. We wanted to know if and how the combination of these two factors may influence the activity of autophagy. In our study, we investigated the role of aging and chronic stress, induced by social isolation in Wistar rats at the age of 6 (N= 16) and 12 (N= 16) months. The animals in experimental groups were separated in the individual cages for 4 weeks. Control groups animals were housed in the pair. We measured the markers of autophagy expression (Beclin-1, LC3-II, mTOR) in the hippocampus and striatum of socially isolated and control groups animals. We measured the expression of NMDA receptor subunits (NR1, NR2A, NR2B) in the hippocampus of the same animals. Our results showed that older...
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The use of tryptophan depletion in the study of the mechanism of action of psychopharmaceuticals
Jirásková, Markéta ; Valeš, Karel (advisor) ; Telenský, Petr (referee)
Tryptophan depletion is a non-pharmacological and non-invasive method extensively used to investigate the role of serotonin (5-hydroxytryptamine in humans and animals. The method is based on reducing the availability of the essential amino acid tryptophan, the dietary serotonin precursor. As a precursor of serotonin, L-Tryptophan has a key role in the regulation of many physiological processes and, inter alia, in the pathology and pathophysiology of neuropsychiatric disorders and diseases. Despite the fact, that the method of tryptophan depletion has been applied in many experimental studies, the exact mechanism, by which tryptophan depletion inducted neurophysiological effects, remain unclear. Also, the protentional use of this method together with other drug coadministration has not been explored in detail yet. In this thesis, the most possible mechanisms of tryptophan depletion are discussed. Biochemical and behavioural effects of low dose of dizocilpine (0.1 mg/kg and 0.15 mg/kg) in animal model of tryptophan depletion are investigated as well. And finally, effects of administration of allopregnanolone and tacrine in model of tryptophan depletion with coadministration of MK-801 are studied. The results show that acute tryptophan depletion with prior starvation, not chronic depletion, caused...
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Effects of Neurotransmission-Modulating Multipotent Compounds in Pharmacological Animal Models of Cognitive Deficit
Chvojková, Markéta ; Valeš, Karel (advisor) ; Kuchař, Martin (referee) ; Rudá, Jana (referee)
In preclinical research on Alzheimer's disease pharmacotherapy, attention is paid to multipotent compounds, enabling intensification of the effect by targeting multiple pathophysiological mechanisms. The aim of the thesis was to assess the effect of multipotent compounds and combination therapy in models of cognitive deficit in the rat. The mechanism of action of the tested compounds was modulation of neurotransmitter systems. The aim of the first part of the study was to compare the effect of experimental monotherapy and combination therapy with an N-methyl-D-aspartate (NMDA) receptor antagonist and a γ-aminobutyric acid type A (GABAA) receptor positive modulator in the trimethyltin-induced model. Superiority of the combination therapy was proven by histological analysis of hippocampal neurodegeneration; however, it did not reach statistical significance in the cognitive test. The other part of the thesis focused on multipotent tacrine derivatives. We demonstrated a positive effect of 6- chlorotacrine-6-nitrobenzothiazole hybrid, as well as 6-chlorotacrine-L-tryptophan hybrid, acting as acetylcholinesterase inhibitors, in the scopolamine-induced model of cognitive deficit. Besides, we demonstrated a low risk of serious side effects of other tacrine derivatives acting as NMDA receptor antagonists....
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The importance of NMDA antagonists in animal models of ischemic injury and major depressive disease
Kletečková, Lenka ; Valeš, Karel (advisor) ; Zach, Petr (referee) ; Ježek, Karel (referee)
Glutamatergic system is the main excitatory system and glutamatergic receptors are the most abundantly expressed in whole central nervous system. The most widespread type of glutamatergic receptors are N-methyl-D-aspartate (NMDA) receptors which are essential for physiological development of nervous tissue, synaptic plasticity and cognitive processes. On the other hand, over-activation of these receptors leads to excitotoxic damage of nervous tissue and serious neurological consequences for future quality of life. Disruption of glutamatergic system is common feature for hypoxic-ischemic damage, traumatic brain injury, neurodegenerative and neuropsychiatric diseases. Therefore glutamatergic system and specifically NMDA receptors are an attractive target for neuropharmacological research. Presented thesis explores the effect of several molecules with modulating inhibiting effect on NMDA receptor. Work is preferentially focused on application research; the main aim is evaluated therapeutic potential of studied compounds. First group of compounds is represented by neuroactive steroids pregnanolone glutamate and pregnanolone hemipimelate, which are allosteric inhibitors of NMDA receptor. Here, their neuroprotective effect is demonstrated in hypoxic-ischemic and excitotoxic damage of nervous tissue....
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Influence of intestinal microbiota on development of neurodegenerative diseases
Hakenová, Kristina ; Valeš, Karel (advisor) ; Vodička, Martin (referee)
Aging is associated with natural biological changes, which result in a decrease in the functional capacity of the body, which is also accompanied by an increased incidence of inflammatory processes that contribute to the development of neurodegeneration. The intestinal microbiota and its interaction with the intestine and the central nervous system play a key role in maintaining the function of biological homeostatic systems at an older age. This opens the possibility of influencing or modifying human microbiota for the development of therapeutic strategies. Based on the analysis of stool samples by HPLC MS / MS, the study confirmed the effect of selected probiotics on the modification of metabolic pathways and the proper functioning of the microbiota per se. The greatest effects were observed on tyrosine metabolism, tryptophan metabolism, arachidonic acid metabolism and bile acid biosynthesis metabolism. A positive effect of selected probiotic bacteria was found in the memory component of cognitive functions. Significant improvements were observed in verbal learning and verbal memory. In subjects with mild cognitive impairment, the progression of cognitive deficit has been slowed. Significant improvement was also observed for executive functions. These findings were not followed by a subjective...
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Optical Signals of Brain
Konopková, Renata ; Otáhal, Jakub (advisor) ; Kittnar, Otomar (referee) ; Valeš, Karel (referee)
Intrinsic optical signals are the signals reflecting changes in transmittance or reflectance of the light illumitating the tissue. Registration of such changes can be applied for the detection of physiological condition in the slices of biological tissues (in vitro) or in the whole animal (in vivo). The aim of this project is to introduce this topic and show different possibilities for the detection of changing optical properties of nervous tissue both in vitro and in vivo. The detection system of both light source and attachment of the optical fibre to the skull of the animal for in vivo experimets have been designed. The proper experimental part of the study have been done in hippocampal tissue slices and shows the correlation of the tissue activity and the optical signal at level of ion channels, glutamatergic synaptic activity, glial component of the signal and mitochondrial signal. We are dealing with the source of the noice that we record while detecting rather subtle changes of optical properties. We are indroducing the software VisionBrain for synchronous detection of both electrical and optical changes. Keywords: Intrinsic optical signals, hippocampus, imaging, biomechanics
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