National Repository of Grey Literature 45 records found  beginprevious13 - 22nextend  jump to record: Search took 0.00 seconds. 
Modulation of synaptic transmission, studies on spinal cord slices in vitro
Mrózková, Petra ; Paleček, Jiří (advisor) ; Krůšek, Jan (referee)
Modulation of a synaptic transmission in the spinal cord dorsal horn plays a key role in nociceptive signalling, especially in states of pathological pain. The goal of this study was to develop a method for calcium imaging in spinal cord slices in vitro. This method allowed us to record changes of intracellular free calcium ions concentration (iCa2+ ), that are a major mediator of neuronal plasticity. In this work, we have focused on application of this method in a conventional fluorescence microscope and on the role of different neuromodulators of synaptic activity. Changes of iCa2+ induced by dorsal root electrical stimulation were recorded altogether in 744 dorsal horn (lamina I and II) neurons. In the first series of experiments, stimulation protocols activating preferentially A and A + C dorsal root fibers were used and long-term stability of the calcium responses was verified. The dorsal root stimulation induced in the neurons fast and delayed type of calcium response. Application of AMPA and NMDA receptors antagonists, CNQX (50μM) and MK801 (45μM), reduced the calcium response amplitude and confirmed the importance of glutamate receptors in synaptic activation. In several experiments the effect of capsaicin a TRPV1 receptors agonist, application was tested. Application of even low...
Molecular mechanisms of activation and modulation of TRPV3 receptor
Chvojka, Štěpán ; Vlachová, Viktorie (advisor) ; Novotný, Jiří (referee)
Transient receptor potential vanilloid 3 receptor channel (TRPV3) is a thermosensitive ion channel expressed in skin keratinocytes. There, in a molecular complex with the epidermal growth factor receptor (EGFR) contributes to proliferation and terminal differentiation of keratinocytes, temperature detection, pain and pruritus. TRPV3 is activated by a number of exogenous compounds, such as carvacrol from oregano, thymol from thyme and eugenol from clove. Its unique feature is sensitization, TRPV3 channel activity successively increases upon repeated stimulation. The molecular basis of this process is not yet understood. One of the considered possibility is a direct phosphorylation of TRPV3 protein through signaling pathways involving EGFR and mitogen-activated protein kinase MAPK1 / MAPK3 (also called ERK2 / ERK1). In this thesis we investigated whether sensitization of TRPV3 which is expressed in a human cell line immortalized keratinocytes could be influenced by mutations on the predicted consensual phosphorylation sites for MAPK1 / MAPK3. We used electrophysiological patch-clamp technique and tested eight mutants, in which was threonine or serine replaced with aspartic acid mimicking phosphorylation. We identified six residues where the mutations influenced at least one of the functional...
Structural basis for interspecies differences in the TRPA1 receptor activation
Synytsya, Viktor ; Šulc, Miroslav (advisor) ; Hudeček, Jiří (referee)
Ankyrin transient receptor potential channel TRPA1 is an excitatory ion channel that transduces nociceptive information on primary aferent sensory nerves of mammals and other organisms. Structure function studies on TRPA1 are valuable for understanding the mechanisms of channel activation and for specific drug discovery efforts, however, significant interspecies differences hamper direct transfer of findings in animals to human. On the other hand, the interspecies differences may prompt identification of many important functional domains. The aim of this bachelor thesis is to give an overview of recent evidence regarding the functional and structural properties of human TRPA1 ion channels from the point of view of the comparison of the most important interspecies differences among TRPA1 orthologs. The experimental part is focused on the comparison of activation properties of human TRPA1 channel with a chimera in which the fifth transmembrane region was replaced by that from Drosophila melanogaster. The presented results obtained by electrophysiological technique patch-clamp demonstrate that outward membrane currents induced by depolarizing voltage are significantly reduced in chimera, which indicates an important role of the fifth transmembrane domain in TRPA1 channel gating (In Czech). Key words:...
Incidence and Properties of Thermosensitive TRP Ion Channels in Cellular Models of Sensory Neurones
Loudová, Leona ; Vlachová, Viktorie (advisor) ; Boušová, Kristýna (referee)
Primary afferent sensory neurons enable all living organisms to survive in their environment and react to dangerous stimuli, including noxious and irritant chemicals, temperature, and pressure. These pseudo-unipolar neurons represent a heterologous population that, depending on functional properties, morphology, receptor equipment, degree of myelination, and conduction velocity, determines the intensity at which a stimulus is converted to an electrical signal that is then conducted to the central nervous system to elicit defensive response. The cell bodies of the peripheral sensory neurons are localized in the dorsal root ganglia (DRG) and cell lines derived from these neurons are intensively used not only to study the mechanisms of pain, but also to rationally search for substances with potential analgesic effect. The main goal of this bachelor's thesis is to summarize the current research on molecular mechanisms of nociception using cell lines derived from DRG neurons with a focus on a specific group of temperature-sensitive transient receptor potential (thermoTRP) ion channels. The aim is to present currently available studies focusing on cellular and molecular differences that result from different methodological approaches to the preparation and cultivation of cell cultures, especially in the...
Modulation of spinal nociceptive mechanisms under pathological conditions
Mužík, David ; Špicarová, Diana (advisor) ; Smejkalová, Terézia (referee)
Pain is a crucial component of the body's innate defenses, which helps us to respond to the damage that is threatening or imminent. If the pain persists even after the injury has healed, or arises for no apparent reason, it itself becomes harmful. Nociception begins with the detection of a noxious stimulus that irritates free nerve endings on the peripheral projections of spinal ganglion neurons. If the stimulus induces depolarization of the cell and an action potential forms, information of the stimulus is conducted by thinly myelinated Aδ fibers, or unmyelinated C fibers to the spinal cord dorsal horn. Here, the first synapses of sensory pathways are located, which allow the transmission of nociception to secondary afferent neurons, and these further direct the information to the higher centers of the CNS. Synapses in the dorsal horn are key to modulating nociceptive signaling, in which the endocannabinoid system, including endogenous cannabinoids and their receptors, plays a significant role. However, under pathological conditions such as the development of neuropathic pain or neuroinflammation, changes in the expression and function of agonists and receptors of the endocannabinoid system occur. These changes are of great importance in the onset and persistence of pathological pain. The study of...
Functional and structural study of thermally activated TRP ion channels: The role evolutionarily conserved motifs in the TRPA1 modulation
Kádková, Anna
Ankyrin receptor TRPA1 is an ion channel widely expressed on primary afferent sensory neurons, where it acts as a polymodal sensor of nociceptive stimuli. Apart from pungent chemicals (e. g. isothiocyanates, cinnamaldehyde and its derivatives, acrolein, menthol), it could be activated by cold temperatures, depolarizing voltages or intracellular calcium ions. TRPA1 channel is a homotetramer in which each subunit consists of cytoplasmic N and C termini and a transmembrane region. The transmembrane part is organized into six alpha- helices connected by intra- and extracellular loops. The N terminus comprises a tandem set of 16 to 17 ankyrin repeats (AR), while the C terminus has a substantially shorter, dominantly helical structure. In 2015, a partial cryo-EM structure of TRPA1 was resolved; however, the functional roles of the individual regions of the receptor have not yet been fully understood. This doctoral thesis is concerned to elucidate the role of highly conserved sequence and structural motifs within the cytoplasmic termini and the S4-S5 region of TRPA1 in voltage- and chemical sensitivity of the receptor. The probable binding site for calcium ions that are the most important physiological modulators of TRPA1 was described by using homology modeling, molecular-dynamics simulations,...
The role of nociceptive synaptic transmission modulation at the spinal cord level in different pain states
Adámek, Pavel
Pain is a common symptom of many clinical syndromes and diseases. In particular, the treatment of neuropathic pain represents a serious public health issue because currently available analgesia is ineffective in many cases or it has adverse effects. Treatment of pain-related suffering requires knowledge of how pain signals are initially generated and subsequently transmitted by the nervous system. A nociceptive system plays a key role in this process of encoding and transmission of pain signals. Modulation of the nociceptive synaptic transmission in the spinal cord dorsal horn represents an important mechanism in the development and maintenance of different pathological pain states. This doctoral thesis has aimed to investigate and clarify some of the mechanisms involved in the modulation of the spinal nociceptive processing in different pain states. The main attention was paid to study the following issues: (I.) Which is the role of Transient Receptor Potential Vanilloid type 1 channels (TRPV1), Toll-Like Receptors 4 (TLR4), and phosphatidylinositol 3-kinase (PI3K) in the development of neuropathic pain induced by paclitaxel (PAC) chemotherapy in acute in vitro, and subchronic in vivo murine model of PAC-induced peripheral neuropathy (PIPN)? (II.) How is affected spinal inhibitory synaptic control...
Effect of foam rolling on mechano-nociceptive and vibrational sensation.
Novotná, Eliška ; Čech, Zdeněk (advisor) ; Demeková, Júlia (referee)
The thesis deals with the evaluation of the influence of foam rolling on selected parameters of somatosensory perception (pressure-algic threshold, vibrotactile sensation). The theoretical part discusses fascial tissue, summarizes the current knowledge of foam rolling and focuses on the mechanisms of pain and vibrotactile sensation. The research part consists of a randomized blind study on a group of 15 healthy probands (11 women, 4 men), which evaluates the effect of foam rolling. The effect is objectivized by pressure algometry and vibrametry on the m. rectus femoris and m. biceps femoris of both lower limbs (measured before and after therapy). The value of the pressure pain threshold (PPT) increased after foam rolling. Vibrotactile threshold (VT) was lower after foam rolling than before its use, which means that vibrotactile sensitivity was increased. The results show that these changes do not occur only in the interventioned m. rectus femoris, but some changes in parameters can be found in other muscles as well. Keywords fascial tissues, foam rolling, pressure algometry, pressure pain treshold, PPT, vibrametry, somatosensory system, nociception, diffuse noxious inhibitory control, DNIC
Neuroinflammation and mechanisms of neuropathic pain development
Kalynovska, Nataliia ; Paleček, Jiří (advisor) ; Krůšek, Jan (referee) ; Hejnová, Lucie (referee)
Neuropathic pain represents a possible outcome of neural tissue injury; it occurs also as a concomitant symptom of different diseases or as a side effect of several treatments. Up to date, it constitutes a great challenge in clinical practice, as currently available treatments are still unsatisfactory. Mechanism-based treatment approaches are promising strategy in neuropathic pain management. However, there is still a lack of information about the exact mechanisms involved in the development and/or maintenance of neuropathic pain. This Doctoral Thesis is aimed to explore the mechanisms underlying the development of neuropathic pain states in different models. The principal part of this work is focused on the study of anti-inflammatory effect of Angiotensin II receptor type 1 (AT1R) blocker, losartan, in two different models of peripheral neuropathy: paclitaxel-induced peripheral neuropathy (PIPN) and spinal nerve ligation (SNL). The work also aimed to access the involvement of spinal transient receptor potential vanilloid type 1 (TRPV1) channels in the process of neuronal activation induced by paclitaxel (PAC) and chemokine CCL2 treatment. In order to fulfil the abovementioned aims, behavioral, immunohistochemical and molecular methods were used. For every model of peripheral neuropathy, the...
Mechanisms of Activation and Modulation of Ion Channels Specific for Nociceptive Neurones
Touška, Filip ; Vlachová, Viktorie (advisor) ; Paleček, Jiří (referee) ; Tureček, Rostislav (referee)
Human body detects potentially damaging stimuli by specialized sensory nerve endings in the skin, the nociceptors. Their membranes are equipped with ion channels, molecular sensors, coding the outside stimuli into the trains of action potentials and conducting them to the higher brain centers. The most prominent group of transduction ion channels is the transient receptor potential (TRP) channel family followed by ion channels responsible for generation and conduction of action potentials from the periphery to the brain, the voltage-gated sodium channels (VGSCs). Understanding the mechanisms how particular stimulus is encoded and processed is of particular importance to find therapeutics for various types of pain conditions. We characterized the properties of VGSC subtypes NaV1.9 and NaV1.8 at high temperatures. We showed that NaV1.9 undergo large increase in current with increasing temperatures and significantly contribute to the action potential generation in dorsal root ganglion (DRG) neurons. Ciguatoxins (CTXs) are sodium channels activator toxins causing ciguatera fish poisoning, a disease manifested by sensory and neurological disturbances. We elucidated the mechanism of CTX- induced cold allodynia, a pathological phenomenon where normally innocuous cool temperatures are perceived as pain. We...

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