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The role of AQP4 and TRPV4 channels in the ischemic brain edema: focusing on glial cells
Kročianová, Daniela ; Anděrová, Miroslava (advisor) ; Máčiková, Lucie (referee)
Cerebral ischemia, also known as stroke, is one of the most common causes of death. It is accompanied by the formation of edema, which can be characterized as an influx of water and osmolytes into the brain, causing volume alterations. We recognize two types of cerebral edema - vasogenic, characterized by the disruption of the blood-brain barrier (BBB) and increase of the extracellular volume, and cytotoxic, caused by the increase of the volume of cells, mainly glia. The major contributors to the formation of cytotoxic edema are the astrocytes, which, in physiological conditions, are responsible for the maintenance of the BBB and keeping the homeostasis of the brain and spinal cord or central nervous system. The mechanism responsible for the process of volume and osmotic changes are the transmembrane channels, mainly aquaporin 4 (AQP4) and transient receptor potential vanilloid 4 (TRPV4). AQP4 is the main pathway for water influx as well as efflux when the edema subsides. TRPV4 is likely responsible for the maintenance of the osmotic balance of the organism, although its precise role in the formation of the edema has not yet been fully elucidated. The main aim of this thesis was to categorize the types of cerebral ischemia and edema, and to describe the process of cerebral edema formation and the...
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The role of AQP4 and TRVP4 channels in the ischemic brain edema: focusing on glial cells.
Kročianová, Daniela ; Anděrová, Miroslava (advisor) ; Máčiková, Lucie (referee)
Cerebral ischemia, also known as stroke, is one of the most common causes of death. It is accompanied by the formation of edema, which can be characterized as an influx of water and osmolytes into the brain, causing volume alterations. We recognize two types of cerebral edema - vasogenic, characterized by the disruption of the blood-brain barrier (BBB) and increase of the extracellular volume, and cytotoxic, caused by the increase of the volume of cells, mainly glia. The major contributors to the formation of cytotoxic edema are the astrocytes, which, in physiological conditions, are responsible for the maintenance of the BBB and keeping the homeostasis of the brain and spinal cord or central nervous system. The mechanism responsible for the process of volume and osmotic changes are the transmembrane channels, mainly aquaporin 4 (AQP4) and transient receptor potential vanilloid 4 (TRPV4). AQP4 is the main pathway for water influx as well as efflux when the edema subsides. TRPV4 is likely responsible for the maintenance of the osmotic balance of the organism, although its precise role in the formation of the edema has not yet been fully elucidated. The main aim of this thesis was to categorize the types of cerebral ischemia and edema, and to describe the process of cerebral edema formation and the...
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Electrophysiological characterization of Kir2.1 membrane channel
Měsíčková, Klára ; Chmelíková, Larisa (referee) ; Svoboda, Ondřej (advisor)
The topic of this thesis is electrophysiological characterization of Kir2.1 membrane channel. Inward rectifier potassium channel Kir2.1 is located in muscular, heart and nerve cells and its dysfunction causes various diseases. Practical part of this stage is focused on cultivation of the HEK293T cell line that is used to transfection of the plasmid Kir2.1 and subsequent measurement of the ionic current through the electrophysiological method patch-clamp in whole-cell mode.
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The role of astrocytes in the formation of brain edema
Heřmanová, Zuzana ; Anděrová, Miroslava (advisor) ; Pačesová, Dominika (referee)
Brain edema is a cause of mortality accompanying number of pathologies such as ischemia, traumatic brain injury, tumors or liver and kidney failure. It is described as a process of osmotic and water flux alterations, which lead to cell volume changes and to an increase in intracranial pressure. Brain edema is usually classified into two types: vasogenic and cytotoxic. Development of vasogenic edema is connected to the blood brain barrier disruption. Water accumulates in the extracellular space and exerts pressure on the cellular compartments of the tissue. The cytotoxic type of edema is characterized by water accumulation within the cells. The process of cellular volume enlargement is termed cellular swelling. Cytotoxic swelling is usually connected to glial cells, namely astrocytes, as these cells represent a part of the blood brain barrier and thus they influence homeostasis inside the brain. Water flows across cytoplasmic membrane through a system of specialized channels - aquaporins. For the brain edema formation, aquaporin 4 is the most important. It is localized on astrocytic membranes and using aquaporin-null mice, it has been shown, that it participates in water clearance in physiological and pathological conditions. Since the water fluxes are passive, the driving force for edema formation...
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The influence of stochastic behaviour of ion channels on the signal and information transfer at excitable neuronal membranes
Šejnová, Gabriela ; Kuriščák, Eduard (advisor) ; Maršálek, Petr (referee)
The stochastic behavior of voltage-gated ion channels causes fluctuations of conductances and voltages across neuronal membranes, contributing to the neuronal noise which is ubiquitous in the nervous system. While this phenomenon can be observed also on other parts of the neuron, here we concentrated on the axon and the way the channel noise influences axonal input-output characteristics. This was analysed by working with our newly created computational compartmental model, programmed in Matlab environment, built up using the Hodgkin-Huxley mathematical formalism and channel noise implemented via extended Markov Chain Monte Carlo method. The model was thoroughly verified to simulate plausibly a mammalian axon of CA3 neuron. Based on our simulations, we confirmed quantitatively the findings that the channel noise is the most prominent on membranes with smaller number of Na+ and K+ channels and that it majorly increases the variability of travel times of action potentials (APs) along axons, decreasing thereby the temporal precision of APs. The simulations analysing the effect of axonal demyelination and axonal diameter correlated well with other finding referred in Literature. We further focused on spike pattern and how is its propagation influenced by inter-spike intervals (ISI). We found, that APs fired...
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The role of SGK1 in heart
Havlíková, Nikola ; Horníková, Daniela (advisor) ; Mančíková, Andrea (referee)
Serum and glucocorticoid-regulated kinase 1 (SGK1) is an enzyme which is encoded by the sgk1 gene. This is a dimer. Generally, SGK1 belongs into the protein kinases, but its structure is somehow different from the other protein kinases, especially in the reaction center, which is related to its activity. SGK1 belongs to the subfamily of serine/threonine kinases. This kinase is activated by insulin or growth factors via phosphatidylinositol-3-kinase (PI3K) and mammalian rapamycin mTORC2. SGK1 plays an important role in inflammatory processes, the proliferation and apoptosis. In heart it helps to increase the abundance of proteins, which has affect on the morphology of ion channels and Na+ /K+ -ATPase. The sgk1 gene plays an important role in cellular stress response. This kinase activates potassium, sodium, chloride and calcium channels, which suggests about the involvement in the regulation of processes such as the cell survival, neuronal excitability and renal sodium excretion. Currently, the most discussed roles of SGK1 are in the heart, kidneys, brain, lungs and gastrointestinal tract. In recent years, it was found that SGK1 has different expression and regulation during the developmental stages and pathological conditions such as hypertension, diabetic neuropathy, ischemic trauma and...
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Calcium signalling in astrocytes under physiological and pathological conditions
Svatoňová, Petra ; Anděrová, Miroslava (advisor) ; Kolář, David (referee)
Calcium signalling in astrocytes represents an important component, which enables proper neuronal functioning under physiological conditions. Alterations in Ca2+ signalling, accompanied by an increase in intracellular calcium levels is a hallmark for numerous pathological states of central nervous system, such as traumatic and ischemic brain/spinal cord injuries, epilepsy as well as neurodegenerative diseases, such as Alzheimer's disease and psychiatric disorders, such as schizophrenia. The research analyzing the molecular components of astrocytic Ca2+ signalling can help us understand the control mechanisms used in calcium signalling and thus be greatly beneficial for further therapeutic research. Powered by TCPDF (www.tcpdf.org)
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Membrane properties of NG2 glia in CNS
Knotek, Tomáš ; Anděrová, Miroslava (advisor) ; Hrčka Krausová, Barbora (referee)
NG2 glia represent a new type of glial cells in central nervous system, which does not belong to astrocytes, oligodendrocyte or microglia. and their most frequent marker is chondroitine sulphate proteoglycan NG2. These cells keep their proliferation ability in adult brain and it is generally accepted that they can differentiate into oligodendrocytes. This thesis summarize the current knowledge about membrane properties of NG2 glia, namely expression of numerous types of ion channels and ionotropic and metabotropic receptor on their membrane. NG2 glia express outwardly and inwardly rectifying K+ channels, Ca2+ activated K+ channels and two-pore domain K+ channels. Interestingly, they also express voltage gated Na+ channels, L, T, P/Q and N type Ca2+ channels and voltage gated Cl- channels. Furthermore, nonspecific cationic channels, such as HCN and TRP, were identified in NG2 glia and they express Na+ /Ca2+ exchanger at high level. There are also ionotropic and metabotropic glutamate and GABA receptors on NG2 glia membrane, together with nicotinic and muscarinic receptors, adrenergic and glycine receptors, metabotropic and ionotropic purinergic receptors, receptors for serotonine, dopamine and histamine. Ion channels and receptors in NG2 glia play an important role in their proliferation,...
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Cannabinoid signalling and its physiological significance
Pavluch, Vojtěch ; Novotný, Jiří (advisor) ; Moravcová, Simona (referee)
Lidská společnost je ve styku s kanabinoidními látkami již od starověku. Ať už lidé využívali rostlinnou biomasu nebo bylinné léčitelství, bylo konopí vždy předmětem diskuzí. Poznatky objasňující molekulární principy účinku látek obsažených přírodně jen v konopí jsou však známy jen několik málo desítek let. Cílem této práce je charakterizovat subtypy receptorů, na které se kanabinoidy vážou, molekulární mechanismy jejich působení, následné konsekvence ve fyziologii a také poukázat na potenciální uplatnění jak rostlinných, tak syntetických kanabinoidů v lékařství. Kanabinoidní receptory jsou hojně se vyskytující podskupinou integrálních membránových receptorů, spadající do velké rodiny receptorů spřažených s G-proteiny. Vzhledem k ubikviternímu výskytu v organismu tyto receptory po aktivaci příslušnými lipofilními ligandy ovlivňují celou škálu fyziologických pochodů. Vazba kanabinoidních látek na daný subtyp těchto receptorů spouští specifickou signální kaskádu v buňce a ovlivňuje tak určitým způsobem buněčný metabolismus. Studium kanabinoidních receptorů a jejich ligandů přispívá k porozumění procesům zahrnujícím tvorbu paměti a učení, ale také mechanismům zapojeným v analgézii, imunomodulaci a buněčné proliferaci. Tyto receptory však ovlivňují také fyziologii kardiovaskulárního systému nebo...
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