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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...
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The role of TRPV1 receptors in nociceptive signalling at spinal cord level
Mrózková, Petra ; Paleček, Jiří (advisor) ; Novotný, Jiří (referee) ; Krůšek, Jan (referee)
Modulation of nociceptive synaptic transmission in the spinal cord dorsal horn plays a key role in the development and maintenance of pathological pain states and chronic pain diseases. Important role in this process play Transient receptor potential Vanilloid 1 receptors (TRPV1), present on presynaptic endings of primary afferents in the superficial spinal cord dorsal horn. Changes in TRPV1 activity have significant impact on nociceptive transmission. There are number of processes that influence the function of spinal TRPV1 receptors. This work is focused on the role of protease-activated receptors type 2 (PAR2), C-C motif chemokine ligand 2 (CCL2) and the effect of chemotherapeutic drug paclitaxel in modulation of synaptic nociceptive transmission and activation of TRPV1 receptors. PAR2 receptors belong to a family of four G-protein-coupled receptors activated by proteases. The role of PAR2 receptors in pain perception is closely related to their presence in a population of dorsal root ganglion neurons, where they are also co-expressed with TRPV1. Activation of PAR2 may lead to peripheral and central sensitization. Chemokine CCL2 and its main receptor CCR2 were suggested to be an important factor in the development of neuropathic pain after peripheral nerve injury. In our study we focused on the...
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