Premium
Differential regulation of inositol 1,4,5‐trisphosphate by co‐existing P 2Y ‐purinoceptors and nucleotide receptors on bovine aortic endothelial cells
Author(s) -
Purkiss John R.,
Wilkinson Graeme F.,
Boarder Michael R.
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.tb14797.x
Subject(s) - inositol , purinergic receptor , nucleotide , receptor , inositol phosphate , microbiology and biotechnology , biology , chemistry , neuroscience , biochemistry , gene
1 We have examined the inositol 1,4,5‐trisphosphate (Ins(1,4,5)P 3 ) responses in bovine aortic endothelial (BAE) cells to purines (ATP, ADP and analogues) and the pyrimidine, uridine triphosphate (UTP). 2 Exchange of medium on BAE cells in the absence of agonist was found to be a stimulus for Ins(1,4,5)P 3 generation. BAE cells stimulated with 100 μ m ATP, 30 μ m 2MeSATP (an agonist at P 2Y ‐purinoceptors but not nucleotide receptors) or 100 μ m UTP (an agonist at nucleotide receptors but not P 2Y ‐purinoceptors) gave Ins(1,4,5)P 3 responses above that caused by exchange of medium. The time course was rapid, with peak response within the first 5 s and levels returning close to basal after 30 s of stimulation. 3 Significant differences in Ins(1,4,5)P 3 responses to 100 μ m UTP and 30 μ m 2MeSATP stimulation were observed. The response to UTP was reproducibly more sustained than that to 2MeSATP. 4 Stimulation of BAE cells with 100 μ m UTP plus 30 μ m 2MeSATP produced a response statistically indistinguishable from that predicted by addition of the responses to the two agonists in isolation. 5 The Ins(1,4,5)P 3 response to UTP was attenuated to 25% of control by pretreatment of BAE cells with pertussis toxin. Responses to 2MeSATP and ADP were essentially unaffected. ATP stimulation was reduced to 65% of control. 6 Activation of protein kinase C with tetradecanoyl phorbol acetate (TPA) profoundly inhibited Ins(1,4,5)P 3 responses to 2MeSATP and ADP but had no effect on UTP stimulation. The protein kinase C inhibitor, Ro 31–8220, enhanced responses to 2MeSATP, ADP and ATP but no effect was observed on UTP stimulation. 7 These observations show that nucleotide and P 2Y ‐receptors mobilise the second messenger Ins (1,4,5)P 3 by separate routes resulting in different patterns of generation and suggest that while ATP activates both receptors, ADP principally influences these cells by interacting with the P 2Y ‐purinoceptors.