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Ionotropic glutamate receptors and excitotoxicity
Skřenková, Kristýna ; Vyklický, Ladislav (advisor) ; Moravec, Jan (referee)
Glutamate is the major excitatory neurotransmitter in the mammalian central nervous system and its excitatory role is mediated trough activation of glutamatergic ionotropic receptors which are responsible for synaptic transmission and play an important role in learning and memory formation. However, excessive exposure to glutamate can result in excitotoxicity which may lead to cell death. The following text is focused on one group of glutamate receptors - NMDA receptors. The study of the receptors is in the centre of current neurobiology research because there is a series of experimental and clinical evidences that they directly participate in the development of serious diseases such as Alzheimer's disease, Parkinson's disease, Huntington's disease and may cause neuronal damage in trauma, hypoxia and embolia. The aim of this bachelor thesis is to give a brief overview of current knowledge about the structure and function of NMDA receptors and mechanisms of their activation which leads to excitotoxicity and related neuroprotection.
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Preparation, expression and characterization of mouse GCPIII
Bäumlová, Adriana ; Konvalinka, Jan (advisor) ; Šebo, Peter (referee)
English abstract Glutamate carboxypeptidase II (GCPII, EC 3.4.17.21) is a type II transmembrane glycoprotein which has been discovered in nervous system as an enzyme responsible for the hydrolysis of neuropeptide N-acetyl-L-aspartyl-L-glutamate to N-acetyl-L-aspartate and L-glutamate and that has been hypothesized to influence glutamatergic signaling processes. Except for brain, GCPII was mainly found in prostate, kidney, and small intestine. In small intestine, GCPII cleaves terminal glutamates from polyglutamylated folates facilitating thus absorption of dietary folates. In prostate, this enzyme is known as prostate-specific membrane antigen and is used as a cancer marker. Mus musculus is an important model for studing GCPII and its homologs as a therapeutic target. While human GCPII and its paralog GCPIII are relatively well characterized, no biochemical study of their mouse orthologs is available. That is why mouse glutamate carboxypeptidase III (mGCPIII) was cloned, prepared by recombinant expression in insect cells and characterized. We show that pure mouse GCPIII possesses α-glutamate carboxypeptidase activity which is effectively inhibited by specific inhibitor GCPII, 2-PMPA. We also analyzed sensitivity and specifity of monoclonal antibodies against mouse GCPIII. Immunoblots demonstrate that...
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Circadian system in astrocytes
Ľalíková, Kristýna ; Bendová, Zdeňka (advisor) ; Honc, Ondřej (referee)
The circadian system affects almost all cells in the mammalian body. These cells include astrocytes, which together with microglia and oligodendrocytes represent the main types of glial cells found in the brain. The first chapter of this thesis presents a summary of circadian system characteristics and focuses mainly on the molecular mechanism underlying its functioning. The second chapter is devoted to astrocytes, astrocyte calcium signaling, and the process of gliotransmission. The third and last chapter connects both topics and discusses the circadian system in astrocytes. It presents evidence of astrocytic circadian oscillations existence and physiological consequences of its action. Great attention is paid to circadian rhythms in gliotransmission, with a focus on gliotransmitters ATP and glutamate. As the most impressive output of the circadian system of astrocytes is presented the participation in maintaining the rhythmic activity of the main circadian oscillator located in the suprachiasmatic nucleus of the hypothalamus. Key words: circadian system, clock genes, astrocytes, gliotransmission, calcium signaling, glutamate, ATP
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Effects of NMDA receptor modulators on cell death in models of excitotoxicity in vitro.
Strnadová, Lenka ; Smejkalová, Tereza (advisor) ; Skřenková, Kristýna (referee)
NMDA receptors are ionotropic glutamate receptors (iGluR) activated by the amino acid glutamate and mediating signal transmission in the central nervous system. Their proper activity is essential for synaptogenesis, neuronal plasticity and synaptic transmission. However, excessive activation of NMDAR causes strong influx of calcium ions into neurons which triggers several destructive effects, eventually ending with cell death. This so-called excitotoxicity is present not only in many neurodegenerative diseases, such as Alzheimer's disease or Parkinson's disease, but also in acute pathophysiological conditions, such as stroke or traumatic brain injury. General NMDAR inhibitors that could potentially prevent neuronal excitotoxicity have shown severe negative side effects in models in vivo. On the other hand, selective inhibitors of NMDA receptors with the ability to block the unwanted excessive activity while preserving NMDAR physiological function have shown to be therapeutically useful. This work is going to briefly summarize the knowledge of structure, activation and localization of NMDA receptors, then it is going to describe their rule in mediating neuronal toxicity and a few methods we can use to study excitotoxicity in vitro. Finally, this work will compare the effects of several known NMDAR...
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Role of glutamate in obsessive-compulsive disorder: clinical and experimental findings
Mainerová, Karolína ; Stuchlík, Aleš (advisor) ; Fajnerová, Iveta (referee)
Obsessive - compulsive disorder is a common and chronic illness that decreases quality of life and leads to serious limitations. Its treatment is currently only successful in some patients and many of them remain with their problems without proper help and medication. The exact cause of the disease is not yet known, but the role of the glutamatergic system in the pathophysiology of obsessive-compulsive disorder is apparently very important and its modulation can potentially lead to increase in treatment success. Animal models of genetic, behavioural, pharmacological and optogenetic origins are very useful in gaining new insights into the principles and underlying causes of the disease. Clinical studies indicate the efficacy of glutamatergic modulators for disease manifestations and could serve as new avenues for the development of new drugs. Key words: obsessive-compulsive disorder (OCD); glutamate, animal model, clinical findings
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The interaction of kainate subtypes of glutamate receptors with steroid compounds.
Fraňková, Denisa ; Krůšek, Jan (advisor) ; Adámek, Pavel (referee)
Kainate receptors belong to the family of glutamate receptors, which include NMDA, AMPA and δ receptors. Glutamate receptors are widely found in the brain and therefore they are very dynamically investigated, especially from view of pharmacology, because there is great potential for finding new and more specific modulators which could be used in the treatment of neurodegenerative diseases. The aim of this work was to extend the knowledge about the influence of neurosteroids on homomeric kainate receptors (GluK1, GluK2, GluK3) in which is the study of modulation by neurosteroids still at the beginning. We have investigated interactions of homomeric kainate receptors with selected neurosteroids (pregnenolone sulfate, pregnanolone sulfate, dehydroepiandrosterone, dehydroepiandrosterone sulfate) by using patch clamp method in the configuration of whole-cell recording and also by using microfluorometry. We have found out that the biggest modulating effect on homomeric kainate receptors is caused by pregnenolone sulfate, which inhibits glutamate responses of these receptors. Keywords kainate receptor, glutamate, neurosteroids, steroids, patch-clamp technique
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Neurobiology of hypoxic-ischemic insult in immature brain
Kuchtiak, Viktor ; Valeš, Karel (advisor) ; Hejnová, Lucie (referee)
Pathology of the hypoxic-ischemic insult is very well described in the adult age, whereas the state of knowledge is largely neglected during the perinatal age. Serious insult in the early postnatal age leads often to the permanent neurological consequences or death. Ischemic insult causes over release of the glutamate in a brain tissue. This process is followed by excitotoxic damage of the tissue. Glutamatergic NMDA receptors play a key role in the excitotoxicity. Over-activated NMDA receptors are one of the possible therapeutic approaches against ischemic damage of the brain. Speaking of contemporary projects focusing on perinatal stroke, it is necessary to take into account developmental differences in the brain tissue and the requirements to minimal toxicity of possible drugs. Pharmacotherapies for hypoxic-ischemic damage implemented in the current perinatology are insufficients.
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Neurobiology of hypoxic-ischemic insult in immature brain
Kuchtiak, Viktor ; Valeš, Karel (advisor) ; Hahnová, Klára (referee)
Pathology of the hypoxic-ischemic insult is very well described in the adult age, whereas the state of knowledge is largely neglected during the perinatal age. Serious insult in the early postnatal age leads often to the permanent neurological consequences or death. Ischemic insult causes over release of the glutamate in a brain tissue. This process is followed by excitotoxic damage of the tissue. Glutamatergic NMDA receptors play a key role in the excitotoxicity. Over-activated NMDA receptors are one of the possible therapeutic approaches against ischemic damage of the brain. Speaking of contemporary projects focusing on perinatal stroke, it is necessary to take into account developmental differences in the brain tissue and the requirements to minimal toxicity of possible drugs. Pharmacotherapies for hypoxic-ischemic damage implemented in the current perinatology are insufficients.
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