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Characterization of Na + influx mediated by ATP 4— ‐activated P 2 purinoceptors in PC12 cells
Author(s) -
Choi SeYoung,
Kim KyongTai
Publication year - 1996
Publication title -
british journal of pharmacology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.432
H-Index - 211
eISSN - 1476-5381
pISSN - 0007-1188
DOI - 10.1111/j.1476-5381.1996.tb15489.x
Subject(s) - extracellular , adenosine triphosphate , thapsigargin , cytosol , purinergic receptor , biophysics , intracellular , chemistry , adenosine , biochemistry , biology , enzyme
1 Micromolar levels of extracellular ATP increased cytosolic Na + concentration ([Na + ] i ) as well as cytosolic Ca 2+ concentration ([Ca 2+ ] i ) in PC12 cells. 2 Pretreatment of cells with tetrodotoxin, benzamil or thapsigargin did not alter the ATP‐induced Na + influx. 3 Increased extracellular Mg 2+ concentration decreased the ATP effect. Furthermore, when the extracellular ATP pool was treated to contain corresponding calculated concentrations of ATP 4‐ , the increase in [Na + ] i stayed linked to the ATP 4‐ concentration rather than to the total ATP concentrations in the stimulants. 4 Extracellular ATP does not create nonselective pores as shown by the fact that ethidium bromide does not enter the cells upon ATP stimulation. 5 Among the tested nucleotides, only adenosine 5′‐O‐(3‐thiotriphosphate), 2‐methylthio ATP and 2‐chloro ATP also caused Na + influx. 6 Reactive Blue 2 specifically decreased the ATP effect in a concentration‐dependent manner. 7 The results suggest that extracellular ATP triggers Na + influx through a P 2 purinoceptor which is activated by ATP 4‐ in PC12 cells.