The effect of adenosine triphosphate (ATP) on the intracellular Ca2+ concentration ([Ca2+]i) of cultured neurohypophysial astrocytes (pituicytes) was studied by fluorescence videomicroscopy. ATP evoked a [Ca2+]i increase, which was dose dependent in the 2.5–50 µM range (EC50=4.3 µM). The ATP-evoked [Ca2+]i rise was not modified during the first minute following the removal of external Ca2+. Application of 500 nM thapsigargin inhibited the ATP-dependent [Ca2+]i increase. Caffeine (10 mM) and ryanodine (1 µM) did not affect the ATP-induced [Ca2+]i rise. The pituicytes responded to various P2 purinoceptor agonists with the following order of potency: ATP=ATP[γ-S]=2-MeSATP≥ADP, where ATP[γ-S] is adenosine 5′-O-(3-thiotriphosphate) and 2-MeSATP is 2-methylthio-adenosine-5′-triphosphate. Adenosine, AMP, α,β-methylene adenosine-5′-triphosphate (α,β-MeATP), β,γ methylene adenosine-5′-triphosphate (β,γ-MeATP) and uridine 5′-triphosphate (UTP) were ineffective. The P2 purinoceptor antagonists blocked the ATP-evoked [Ca2+]i increase with the following selectivity: RB-2>suramin>PPADS, where RB-2 is Reactive Blue 2 and PPADS is pyridoxal-phosphate-6-azophenyl-2′,4′-disulphonic acid. The ATP-evoked [Ca2+]i increase was substantially blocked by pertussis toxin treatment, suggesting that it might be mediated by a pertussis-toxin-sensitive G protein. The phospholipase C (PLC) inhibitor U-73122 (0.5 µM) abolished the ATP-evoked [Ca2+]i rise, whereas its inactive stereoisomer U-73343 (0.5 µM) remained ineffective. Our results indicate that, in rat cultured pituicytes, ATP stimulation induces an increase in [Ca2+]i due to PLC-mediated release from intracellular stores through activation of a pertussis-toxin-sensitive, G-protein-linked P2Y receptor.
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Similar content being viewed by others Explore related subjectsDiscover the latest articles and news from researchers in related subjects, suggested using machine learning. Author information Authors and AffiliationsCNRS-UMR 6548, Université de Nice Sophia-Antipolis, Laboratoire de Physiologie Cellulaire et Moleculaire, F-06108 Nice Cedex 2, France e-mail: thirion@hermes.unice.fr Tel.: +33-492-076861; Fax: +33-492-076850, , , , , , FR
Jean-Denis Troadec, S. Thirion, Daniel Petturiti, Marie Thérèse Bohn & Philippe Poujeol
Received: 24 September 1998 / Received after revision: 10 December 1998 / Accepted: 18 December 1998
About this article Cite this articleTroadec, JD., Thirion, S., Petturiti, D. et al. ATP acting on P2Y receptors triggers calcium mobilization in primary cultures of rat neurohypophysial astrocytes (pituicytes). Pflügers Arch 437, 745–753 (1999). https://doi.org/10.1007/s004240050841
Issue Date: March 1999
DOI: https://doi.org/10.1007/s004240050841
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