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Full sensitivity of P 2times2 purinoceptor to ATP revealed by changing extracellular pH
Author(s) -
King Brian F.,
Ziganshina Lilia E.,
Pintor Jesus,
Burnstock Geoffrey
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.tb15293.x
Subject(s) - purinergic receptor , extracellular , adenosine triphosphate , p2y receptor , agonist , biophysics , ppads , chemistry , receptor , biochemistry , neurotransmission , nucleotide , xenopus , biology , gene
A full pharmacological characterization was carried out on a recombinant ATP‐gated ion channel (P 2times2 purinoceptor) expressed in Xenopus oocytes. This slowly‐desensitizing neuronal P 2times2 purinoceptor, activated by ATP (EC 50 = 4.6 ± 1 μ m at pH 7.4; n 4), showed the agonist potency order: ATP ≥ 2‐ MeSATP = ATPγS ≥ ATPαS < < Bz‐ATP. The receptor affinity for ATP was enhanced 5–10 fold by acidifying the bathing solution (to pH 6.5) but was diminished 4–5 fold in an alkaline solution (pH 8.0). The maximum activity of P 2times2 purinoceptors and the activity order of a series of nucleotides were unaltered by changing extracellular pH. Interestingly, ATP sensitivity at a recombinant P 2Y1 , purinoceptor remained unaltered with changing extracellular pH. These results indicate that acidotic conditions in the synaptic cleft could strengthen purinergic transmission at neuronal P 2times2 purinoceptors.