Počet záznamů: 1

Sodium-calcium exchanger and R-type Ca2+ channels mediate spontaneous [Ca2+](i) oscillations in magnocellular neurones of the rat supraoptic nucleus

  1. 1.
    0460343 - FGU-C 2017 RIV DE eng J - Článek v odborném periodiku
    Kortus, Štěpán - Srinivasan, Ch. - Forostyak, O. - Zápotocký, Martin - Ueta, Y. - Syková, E. - Chvátal, A. - Verkhratsky, A. - Dayanithi, G.
    Sodium-calcium exchanger and R-type Ca2+ channels mediate spontaneous [Ca2+](i) oscillations in magnocellular neurones of the rat supraoptic nucleus.
    Cell Calcium. Roč. 59, č. 6 (2016), s. 289-298 ISSN 0143-4160
    Grant CEP: GA ČR(CZ) GBP304/12/G069
    Institucionální podpora: RVO:67985823
    Klíčová slova: magnocellular neurosecretory cells * voltage-gated Ca2+ channels * intracellular Ca2+ stores * Ca2+ imaging * Ca2+ oscillations
    Kód oboru RIV: FH - Neurologie, neurochirurgie, neurovědy
    Impakt faktor: 3.707, rok: 2016

    Isolated supraoptic neurones generate spontaneous [Ca(2+)]i oscillations in isolated conditions. Here we report in depth analysis of the contribution of plasmalemmal ion channels (Ca(2+), Na(+)), Na(+)/Ca(2+) exchanger (NCX), intracellular Ca(2+) release channels (InsP3Rs and RyRs), Ca(2+) storage organelles, plasma membrane Ca(2+) pump and intracellular signal transduction cascades into spontaneous Ca(2+) activity. While removal of extracellular Ca(2+) or incubation with non-specific voltage-gated Ca(2+) channel (VGCC) blocker Cd(2+) suppressed the oscillations, neither Ni(2+) nor TTA-P2, the T-type VGCC blockers, had an effect. Inhibitors of VGCC nicardipine, omega-conotoxin GVIA, omega-conotoxin MVIIC, omega-agatoxin IVA (for L-, N-, P and P/Q-type channels, respectively) did not affect [Ca(2+)]i oscillations. In contrast, a specific R-type VGCC blocker SNX-482 attenuated [Ca(2+)]i oscillations. Incubation with TTX had no effect, whereas removal of the extracellular Na(+) or application of an inhibitor of the reverse operation mode of Na(+)/Ca(2+) exchanger KB-R7943 blocked the oscillations. The mitochondrial uncoupler CCCP irreversibly blocked spontaneous [Ca(2+)]i activity. Exposure of neurones to Ca(2+) mobilisers (thapsigargin, cyclopiazonic acid, caffeine and ryanodine); 4-aminopyridine (A-type K(+) current blocker); phospholipase C and adenylyl cyclase pathways blockers U-73122, Rp-cAMP, SQ-22536 and H-89 had no effect. Oscillations were blocked by GABA, but not by glutamate, apamin or dynorphin. In conclusion, spontaneous oscillations in magnocellular neurones are mediated by a concerted action of R-type Ca(2+) channels and the NCX fluctuating between forward and reverse modes.
    Trvalý link: http://hdl.handle.net/11104/0260447