Mechanisms of Ca2+ mobilization by purinoceptorstimulation and its receptor subtype in cultured rat myenteric neurones

We characterized purinoceptor-mediated changes in intracellular Ca2+ concentration ([Ca2+]i) and membrane currents in cultured rat myenteric neurons using fura-2 ratiometric Ca2+ imaging and whole-cell patch-clamp technique, respectively. ATP (0. 1-300μM) increased [Ca2+]i dose-dependently, which wa...

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Bibliographic Details
Published in:Journal of Pharmacological Sciences 2004, Vol.94 (suppl.2), p.192-192
Main Authors: Toshio Ohta, Akane Kubota, Shigeo Ito
Format: Article
Language:Japanese
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Summary:We characterized purinoceptor-mediated changes in intracellular Ca2+ concentration ([Ca2+]i) and membrane currents in cultured rat myenteric neurons using fura-2 ratiometric Ca2+ imaging and whole-cell patch-clamp technique, respectively. ATP (0. 1-300μM) increased [Ca2+]i dose-dependently, which was greatly decreased by the removal of [Ca2+]o. At a holding potential of -60 mV, ATP evoked an inward current. The current-voltage relation for ATP was characterized by inward rectification and the reversal potential of 0 mV. The potency orders of [Ca2+]i increase and inward current were ATP> ATPγS > CTP> 2MeSATP > BzATP. [Ca2+]i and current responses to ATP were inhibited by P2 antagonists. suramin and PPADS. Zn2+, Cu2+ and low pH increased ATP-induced inward currents. RT-PCR and the immunocytochemical staining revealed the expression P2X2 subtype in rat myenteric neurons. These results suggest that ATP mainly activates ionotropic P2X2 receptors and this results in [Ca2+]i, increase dependent on [Ca2+]o in rat myenteric neurons.
ISSN:1347-8613