Calcium signalling in granule neurones studied in cerebellar slices

Sergej Kirischuk, Nana Voitenko, Platon Kostyuk, Alexej Verkhratsky

    Research output: Contribution to journalArticlepeer-review

    Abstract

    The cytoplasmic free calcium concentration ([Ca2+](i)) was studied in Fura-2/AM loaded granule neurones in acutely prepared cerebellar slices isolated from neonatal (6 days old) and adult (30 days old) mice. Bath application of elevated (10-50 mM) KCl-containing extracellular solutions evoked [Ca2+](i) rise which was dependent on extracellular Ca2+. The K+-induced [Ca2+](i) elevation was inhibited to different extends by verapamil, nickel and ω-conotoxin suggesting the coexpression of different subtypes of plasmalemmal voltage-gated Ca2+ channels. Bath application of caffeine (10-40 mM) elevated [Ca2+](i) by release of Ca2+ from intracellular stores. Caffeine-induced [Ca2+](i) elevation was inhibited by 100 μM ryanodine and 500 nM thapsigargin. Depletion of internal Ca2+ stores by caffeine, or blockade of Ca2+ release channels by ryanodine, did not affect depolarization-induced [Ca2+](i) transients, suggesting negligible involvement of Ca2+-induced Ca2+ release in [Ca2+](i) signal generation following cell depolarization. External application of 100 μM glutamate, but not acetylcholine (1-100 μM), carbachol (10-100 μM) or (1S,3R)-ACPD (100-500 μM) evoked [Ca2+](i) elevation. Part of glutamate-triggered [Ca2+](i) transients in neurones from neonatal mice was due to Ca2+ release (presumably via inositol-(1,4,5)-trisphosphate-sensitive mechanisms) from internal Ca2+ stores. In adult animals, glutamate-triggered [Ca2+](i) elevation was exclusively associated with plasmalemmal Ca2+ influx via both voltage-gated and glutamate-gated channels.
    Original languageEnglish
    Pages (from-to)59-71
    Number of pages12
    JournalCell calcium
    Volume19
    Issue number1
    DOIs
    Publication statusPublished - Jan 1996

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