Functional expression of P2Y purinoceptor in Xenopus oocyte injected with brain mRNA.
Xenopus oocytes injected with embryonic guinea-pig brain mRNA expressed functional P2Y purinoceptors. Extracellular ATP stimulated in a dose-dependent manner a delayed Ca(2+)-dependent Cl- current component. Analysis of the interactions of ATP with compounds that affect Ca2+ fluxes through the plasma membrane or Ca2+ release from internal stores indicates that ATP raises [Ca2+]i by a mechanism that involves activation of voltage-dependent Ca2+ channels, which leads to influx of extracellular Ca2+ into the cells, as well as release of Ca2+ from intracellular stores. Since this phenomenon was not found in control oocytes, it is suggested that brain mRNA encoded for a newly synthesized Ca(2+)-release process stimulated by purinoceptor activation. This mechanism could be largely involved in the short-term regulation of intracellular Ca2+ level involved in ATP neuromodulation functions.
Honoré
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E
Laboratorie de Physiologie Cellulaire UFR de Biologie, Université des Sciences et Techniques de Lille-Flandres-Artois, Villeneuve d'Ascq, France.
Fournier
F
F
Collin
T
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Nargeot
J
J
Guilbault
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P
D000255:Adenosine Triphosphate / Q000494:pharmacology; D000818:Animals; D001921:Brain / Q000378:metabolism*; D002118:Calcium / Q000378:metabolism / Q000502:physiology; D015220:Calcium Channels / Q000502:physiology; D002712:Chlorides / Q000502:physiology; D004594:Electrophysiology; D006168:Guinea Pigs / Q000196:embryology / Q000378:metabolism; D007267:Injections; D009865:Oocytes / Q000378:metabolism* / Q000502:physiology; D012333:RNA, Messenger / Q000378:metabolism / Q000494:pharmacology*; D011983:Receptors, Purinergic / Q000378:metabolism*; D014981:Xenopus
D015220:Calcium Channels; D002712:Chlorides; D012333:RNA, Messenger; D011983:Receptors, Purinergic; D000255:Adenosine Triphosphate; D002118:Calcium