Dorsal fibers Dotaz Zobrazit nápovědu
In polarized motile cells, stress fibers display specific three-dimensional organization. Ventral stress fibers, attached to focal adhesions at both ends, are restricted to the basal side of the cell and nonprotruding cell sides. Dorsal fibers, transverse actin arcs, and perinuclear actin fibers emanate from protruding cell front toward the nucleus and toward apical side of the cell. Perinuclear cap fibers further extend above the nucleus, associate with nuclear envelope through LINC (linker of nucleoskeleton and cytoskeleton) complex and terminate in focal adhesions at cell rear. How are perinuclear actin fibers formed is poorly understood. We show that the formation of perinuclear actin fibers requires dorsal stress fibers that polymerize from focal adhesions at leading edge, and transverse actin arcs that are interconnected with dorsal fibers in spots rich in α-actinin-1. During cell polarization, the interconnected dorsal fibers and transverse arcs move from leading edge toward dorsal side of the cell. As they move, transverse arcs associate with one end of stress fibers present at nonprotruding cell sides, move them above the nucleus thus forming perinuclear actin fibers. Furthermore, the formation of perinuclear actin fibers induces temporal rotational movement of the nucleus resulting in nuclear reorientation to the direction of migration. These results suggest that the network of dorsal fibers, transverse arcs, and perinuclear fibers transfers mechanical signal between the focal adhesions and nuclear envelope that regulates the nuclear reorientation in polarizing cells.
- MeSH
- aktinin fyziologie MeSH
- aktiny fyziologie MeSH
- buněčné jádro fyziologie MeSH
- buněčné linie MeSH
- buněčný převod mechanických signálů fyziologie MeSH
- fibroblasty fyziologie MeSH
- fokální adheze fyziologie MeSH
- kontraktilní svazky fyziologie MeSH
- krysa rodu rattus MeSH
- lidé MeSH
- pohyb buněk fyziologie MeSH
- pohyb fyziologie MeSH
- polarita buněk fyziologie MeSH
- zvířata MeSH
- Check Tag
- krysa rodu rattus MeSH
- lidé MeSH
- zvířata MeSH
- Publikační typ
- úvodníky MeSH
Anesthetic and surgical procedures and an electrophysiological method were developed for recording nerve conduction velocity (NCV) of CNS fibers in the murine spinal cord. Under intravenous anesthesia and artificial ventilation the lumbar spinal cord segments L1 to L4 and dorsal roots L3 to L5 on the left side were exposed by laminectomy. After stimulation of the dorsal root L4, a compound action potential (CAP) was recorded at the ipsilateral left fasciculus gracilis at the spinal cord level L1. The latency from stimulation to the CAP together with the measured distance between the electrodes was used for the determination of the NCV. NCV of the fastest fibers in the fasciculus gracilis was observed to be approximately 28 m/s. Reversible decrease of the NCV was measured, in vivo, under general hypothermia. The technique described serves for in vivo electrophysiological investigations of spinal central fibers in wildtype and mutant mice.
- MeSH
- elektronová mikroskopie MeSH
- krysa rodu rattus MeSH
- mechanoreceptory transplantace MeSH
- nervová vlákna fyziologie ultrastruktura MeSH
- nervová zakončení metabolismus ultrastruktura MeSH
- nervový systém - fyziologické jevy MeSH
- nervový systém MeSH
- regenerace nervu MeSH
- spinální ganglia fyziologie ultrastruktura MeSH
- zvířata MeSH
- Check Tag
- krysa rodu rattus MeSH
- zvířata MeSH
Mnohé práce dokázali, že blokátory L-typu, N-typu and P-typu Ca2+ kanálov môžu zabrániť vzniku hyperalgézie, alodynie alebo zápalových procesov pri modeloch chronickej bolesti, ktoré sú často sprevádzané výraznou precitlivenosťou a plasticitou. Vzhľadom k našim predchádzajúcim výsledkom, ktoré poukazujú na zvýšenú expresiu N-typu Ca2+ kanála v mieche po lézii periférneho nervu, v súčasnej práci sledujeme distribúciu α1B podjednotky N-typu Ca2+ kanála v príslušných spinálnych gangliách (DRGs) v rovnakom modeli neuropatickej bolesti počas 28 dňového prežívania. Imunocytochemické analýzy α1B podjednotky v kontralaterálnych, nepoškodených lumbálnych (L4–L6) DRGs ukázali rovnomerné difúzne sfarbenie tiel všetkých gangliových buniek. Počiatočné zvýšenie α1B podjednotky bolo pozorované výhradne na ipsilaterálnej strane príslušných DRGs, a to len v malých bunkách počas 4dňového prežívania. Avšak výrazný nárast α1B podjednotky bol zaznamenaný počas 7–10dňového prežívania v malých, stredných, veľkých bunkách ale aj v nervových vláknách DRGs. Toto zvýšenie pretrvalo pri dlhodobom prežívaní – 28 dní len v malých bunkách, avšak v stredných a veľkých bunkách došlo k poklesu imunoreaktivity na kontrolné hladiny. Výrazné zmeny boli pozorované výhradne v ipsilaterálnych DRGs L5–L6. Dané výsledky predpokladajú, že zvýšenie α1B podjednotky v príslušných DRGs a jeho následná dlhodobá selektívna expresia v malých neurónoch pravdepodobne zohráva dôležitú úlohu nielen pri počiatočnej iniciácii, ale aj pri pretrvávaní stavu neuropatickej bolesti.
Many studies have shown that L-type, N-type and P-type Ca2+channel blockers may prevent development of hyperalgesia, allodynia or inflammation in persistent pain models where sensitisation and plasticity are present. Therefore, in addition to our previous data indicating increased N-type Ca2+channel expression in the spinal cord after peripheral nerve lesion, here we have characterized α1B subunit in the corresponding dorsal root ganglion neurons (DRGs) following same injury model during 28 days survival. Immunocytochemical analysis of the α1B subunit in the contralateral-non ligated lumbar (L4–6) DRGs showed smooth diffuse staining pattern over the soma of all ganglion neurons. Initial α1B subunit elevation was seen ipsilaterally in small diameter DRGs at 4 days, however majority of ganglion cells (small, medium, large) as well as nerve fibers revealed increased α1B subunit immunoreactivity (IR) after 7–10 days post lesion. Moreower, this Ca2+channel upregulation persisted only in small diameter DRGs up to 28 days, whereas the positivity in medium and large-sized DRGs completelly disappeared. Distinct changes were typically seen in the DRGs L5–L6, while the L4 ganglia showed only light increase of the N-type Ca2+ channel IR in the neuronal bodies. This findings suggest, that upregulation of α1B subunit in corresponding DRGs and its persistance, especially in small diameter neurons probably play an important role not only in the initiation, but also in the maintenance of neuropathic pain state.
- MeSH
- blokátory kalciových kanálů MeSH
- bolest etiologie MeSH
- finanční podpora výzkumu jako téma MeSH
- imunochemie metody MeSH
- krysa rodu rattus MeSH
- modely u zvířat MeSH
- spinální ganglia anatomie a histologie cytologie MeSH
- vápníkové kanály - typ L analýza MeSH
- vápníkové kanály - typ N analýza MeSH
- zvířata MeSH
- Check Tag
- krysa rodu rattus MeSH
- zvířata MeSH
BACKGROUND: Allodynia and hyperalgesia present after surgical interventions are often a major complain of surgical patients. It is thought that both peripheral and central mechanisms contribute to these symptoms. In this study, the role of peripheral nerve fibres that express transient receptor potential vanilloid 1 (TRPV1) receptors in the activation of spinothalamic tract (STT) and postsynaptic dorsal column (PSDC) neurons was assessed in a model of surgical pain. METHODS: Spinothalamic tract and PSDC neurons retrogradely labelled from the thalamus and nucleus gracilis were used. Activation of these projection neurons was evaluated after plantar incision as expression of the early gene product, c-Fos protein, in the nuclei of these neurons. RESULTS: There was a robust increase in c-Fos immunopositivity in the STT and PSDC neurons, in the control animals after a plantar incision. This increase in c-Fos expression was significantly attenuated in animals in which a single high-concentration capsaicin injection was made intradermally at the incision site 24 h before the surgery. CONCLUSIONS: Our results suggest that activation of both STT and PSDC neurons is involved in development of pain states present after surgical incision and that TRPV1-containing peripheral nerve fibres are needed for c-Fos expression in these dorsal horn neurons after plantar incision.
- MeSH
- buňky zadních rohů míšních metabolismus MeSH
- kapsaicin aplikace a dávkování farmakologie MeSH
- kationtové kanály TRPV metabolismus MeSH
- krysa rodu rattus MeSH
- látky ovlivňující senzorický systém aplikace a dávkování farmakologie MeSH
- medulla oblongata metabolismus MeSH
- modely nemocí na zvířatech MeSH
- nervová vlákna * účinky léků metabolismus MeSH
- pooperační bolest * farmakoterapie etiologie metabolismus MeSH
- potkani Wistar MeSH
- protoonkogenní proteiny c-fos účinky léků metabolismus MeSH
- tractus spinothalamicus účinky léků metabolismus MeSH
- zvířata MeSH
- Check Tag
- krysa rodu rattus MeSH
- mužské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Basal extracellular concentrations of 9 amino acids (AAs: aspartate, Asp; glutamate, Glu; asparagine, Asn; serine, Ser; glycine, Gly; threonine, Thr; alanine, Ala; taurine, Tau; and glutamine, Gln) were determined in the spinal cord dorsal horn of anesthetized rats using microdialysis and HPLC techniques. The concentrations of all measured AAs but Gln increased significantly (P < 0.05) during sciatic nerve stimulation at C-fiber strength. The concentration of Tau remained elevated following stimulation, while the other AAs returned to prestimulation values. Addition of the specific non-NMDA antagonist, CNQX, to the perfusing solution prevented the nerve stimulation-evoked AA release. Since the measured increases in extracellular AA concentrations are probably mainly due to activation of interneurons, these results suggest that blockade of non-NMDA receptors prevented activation of interneurons in the dorsal horn and support a major role of non-NMDA receptors at the first synapse of primary afferent fibers in the dorsal horn. Complete block of AA release and decreased basal levels of Glu after infusion of TTX into the dorsal horn also implies increased neuronal activity as the main source of higher AA levels during nerve stimulation.
- MeSH
- 6-kyano-7-nitrochinoxalin-2,3-dion MeSH
- aminokyseliny * metabolismus MeSH
- chinoxaliny * farmakologie MeSH
- elektrická stimulace MeSH
- krysa rodu rattus MeSH
- mícha fyziologie metabolismus účinky léků MeSH
- nervová vlákna fyziologie MeSH
- nervus ischiadicus * fyziologie MeSH
- potkani Sprague-Dawley MeSH
- receptory N-methyl-D-aspartátu fyziologie MeSH
- receptory neurotransmiterů * antagonisté a inhibitory fyziologie MeSH
- tetrodotoxin farmakologie MeSH
- zvířata MeSH
- Check Tag
- krysa rodu rattus MeSH
- mužské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- práce podpořená grantem MeSH
- Research Support, U.S. Gov't, P.H.S. MeSH
- MeSH
- krysa rodu rattus MeSH
- mechanoreceptory MeSH
- mícha MeSH
- nervová vlákna MeSH
- zvířata MeSH
- Check Tag
- krysa rodu rattus MeSH
- zvířata MeSH
