Bradykinin stimulated PGE2 production is independent of changes in intracellular calcium in MDCK cells.
In order to assess whether changes in intracellular Ca2+ are necessary for bradykinin stimulated activation of phospholipase A2 and PGE2 production, MDCK cells were treated with phorbol myristate acetate (PMA) and Lanthanum (La3+). 100 nM PMA reduced peak BK (1 uM) stimulated Ca2+ to 44.0 +/- 11.4% of control, while 1 mM LaC13 reduced peak Ca2+ to 43.5 +/- 12.2% of control. Addition of both PMA and LaC13 reduced the BK stimulated change in intracellular Ca2+ to 8.3 +/- 1.0% of control. In contrast, La3+ did not reduce PGE2 production in response to 10(-7) M to 10(-5) M BK. PMA stimulated PGE2 production, as shown previously. Addition of both PMA and La3+ at doses capable of reducing Ca2+ changes to less than 10% of normal, failed to block BK induced PGE2 production. Therefore, BK stimulated PLA2 activation and PGE2 production can be dissociated from changes in intracellular Ca2+ and suggest that BK activates PLA2 through a mechanism other than by increases in intracellular Ca2+.
Coyne
D W
DW
Department of Medicine, Washington University School of Medicine, St. Louis, Missouri 63110.
Mordhorst
M
M
Bertrand
W
W
Morrison
A R
AR
D000818:Animals; D001920:Bradykinin / Q000494:pharmacology*; D002118:Calcium / Q000378:metabolism*; D002460:Cell Line; D015232:Dinoprostone / Q000096:biosynthesis*; D007700:Kinetics; D007811:Lanthanum / Q000494:pharmacology; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology
C028521:lanthanum chloride; D007811:Lanthanum; D015232:Dinoprostone; D013755:Tetradecanoylphorbol Acetate; D001920:Bradykinin; D002118:Calcium