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Effects of purinoceptor agonists on cytosolic Ca 2+ concentration in swine tracheal smooth muscle cells in culture
Author(s) -
Sawai Hiroko,
Wang Ruixia,
Yamashita Toshikazu,
Kokubun Shinichiro
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.tb15705.x
Subject(s) - extracellular , suramin , adenosine triphosphate , adenosine , purinergic receptor , intracellular , inositol , biochemistry , biology , chemistry , receptor
1 The effects of various purinoceptor agonists on intracellular Ca 2+ concentration ([Ca 2+ ] i ) in swine tracheal smooth muscle cells in primary culture were examined to investigate the subtype of purinoceptors in these cells. 2 ATP (1 μ m to 1 mM) concentration‐dependently increased [Ca 2+ ] i which was measured by monitoring the fluorescence signal of fura2. 3 α, β‐Me ATP at concentrations higher than 10 μ m increased [Ca 2+ ] i in the presence of extracellular Ca 2+ . Responses to the drug were 12 ± 5 and 61 ± 4% of responses to ATP (100 μ m ) at 100 μ m and 1 mM, respectively ( n = 7). The response to 100 μ m ATP was inhibited by 62% in the presence of 1 mM α, β‐Me ATP ( n = 8), though the drug at concentrations lower than that did not affect the response to ATP. 4 ATP increased [Ca 2+ ] i in the absence of extracellular Ca 2+ . The response to ATP in this condition was 40% of that in the presence of extracellular Ca 2+ ( n = 8). 5 Neither cibacron blue 3GA (10 μ m ) ( n = 8) nor suramin (10 and 100 μ m ) ( n = 10) affected the response to ATP (1 μ m to 100 μ m ). 6 The rank order of potency in the absence of extracellular Ca 2+ was UTP> ATP> adenosine 5′‐o‐(3‐thiotriphosphate)>> ADP = α, β‐methylene adenosine 5′‐triphosphate > 2‐(methylthio)‐adenosine 5′‐(tetrahydrogen triphosphate). 7 UTP (1 μ m to 100 μ m ) concentration‐dependently increased inositol 1,4,5‐triphosphate (IP 3 ) production. 8 These results suggest that the increase in [Ca 2+ ] i induced by purinoceptor agonists is mediated mainly via a nucleotide receptor in swine tracheal smooth muscle cells in primary culture.