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Characterization of the effects of 2‐methylthio‐ATP and 2‐chloro‐ATP on brain capillary endothelial cells: similarities to ADP and differences from ATP
Author(s) -
Vigne Paul,
Feolde Erick,
Breittmayer Jean Philippe,
Frelin Christian
Publication year - 1994
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.1476-5381.1994.tb13146.x
Subject(s) - biology , extracellular , intracellular , phospholipase c , adenosine triphosphate , inositol , inositol trisphosphate , phospholipase , biochemistry , inositol phosphate , microbiology and biotechnology , biophysics , enzyme , receptor
1 Brain capillary endothelial cells responded to 2‐methylthio‐ATP (2MeSATP) by large increases in [Ca 2+ ] i (EC 50 = 27 n m ) that were partially dependent on the presence of extracellular Ca 2+ and that were not associated with a measurable production of inositol phosphates. 2 2‐chloro‐ATP (2ClATP) raised [Ca 2+ ] i in a biphasic manner. At low concentrations, intracellular Ca 2+ mobilization was not associated with a measurable production of inositol phosphates. At concentrations >30 μ m , 2ClATP activated phospholipase C. 3 The actions of 2ClATP, 2MeSATP and ADP on [Ca 2+ ] i were additive to those of ATP and UTP. Non‐additive actions of 2MeSATP and of low concentrations of ADP or of 2ClATP were observed. 4 Cross desensitizations of the actions of ADP, 2MeSATP and 2ClATP were observed. None of them desensitized cells to the action of ATP. 5 It is concluded that 2MeSATP and low concentrations of 2ClATP and ADP induce intracellular Ca 2+ mobilization by acting via an atypical P 2y purinoceptor that is not coupled to phospholipase C. At high concentrations, 2C1ATP also activates phospholipase C and further increases [Ca 2+ ] i probably by acting on P 2u purinoceptors.