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Bromoenol lactone enhances the permeabilization of rat submandibular acinar cells by P2X 7 agonists
Author(s) -
Chaïb N,
Kabré E,
Alzola E,
Pochet S,
Dehaye J P
Publication year - 2000
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 - 10.1038/sj.bjp.0703124
Subject(s) - ethidium bromide , digitonin , purinergic receptor , agonist , submandibular gland , phospholipase a , chemistry , endocrinology , acinus , medicine , receptor , biochemistry , biology , microbiology and biotechnology , phospholipase a2 , enzyme , pancreas , dna
The permeabilizing effect of P2X 7 agonists was tested in rat submandibular acinar cells using the uptake of ethidium bromide as an index. The uptake of ethidium bromide by acini incubated at 37°C in the presence of 1 m M ATP increased with time and reached after 5 min about 10% of maximal uptake measured in the presence of digitonin. The response to ATP was dose‐dependent (half‐maximal concentration around 40 μ M ) and it was decreased when the temperature was lowered to 25°C. Benzoyl‐ATP reproduced the response to ATP (half‐maximal concentration around 10 μ M ). UTP or 2‐methylthioATP had no effect. The permeabilization in response to ATP was blocked by oxidized ATP and by magnesium and inhibited by Coomassie blue. ATP increased the activity of a calcium‐insensitive phospholipase A 2 (iPLA 2 ). Bromoenol lactone (BEL) inhibited the iPLA 2 stimulated by ATP but potentiated the uptake of ethidium bromide in response to the purinergic agonist. From these results it is concluded that the activation of P2X 7 receptors permeabilizes rat submandibular acinar cells. The pore‐forming activity of the receptor might be negatively regulated by the concomitant activation of the iPLA 2 by the receptor.British Journal of Pharmacology (2000) 129 , 703–708; doi: 10.1038/sj.bjp.0703124