Involvement of phosphatidylcholine hydrolysis by phospholipase D in extracellular ATP-induced arachidonic acid release in aortic smooth muscle cells.
We investigated the effect of extracellular ATP on phosphatidylcholine-hydrolyzing phospholipase D activity and the role of phospholipase D activation in extracellular ATP-induced arachidonic acid release in cultured rat aortic smooth muscle cells. ATP significantly stimulated the formation of choline in a dose-dependent manner in the range between 0.01 and 0.5 mmol/L. However, ATP had no effect on the formation of phosphocholine. Staurosporine, an inhibitor of protein kinases, did not affect the ATP-induced formation of choline. ATP significantly stimulated arachidonic acid release in a dose-dependent manner in the range between 0.01 and 0.5 mmol/L. DL-Propranolol hydrochloride (propranolol), an inhibitor of phosphatidic acid phosphohydrolase, significantly inhibited the ATP-induced release of arachidonic acid. 1,6-Bis(cyclohexyloximinocarbonylamino)-hexane (RHC-80267), a potent and selective inhibitor of diacylglycerol lipase, reduced ATP-induced arachidonic acid release. Quinacrine, a phospholipase A2 inhibitor, suppressed ATP-induced arachidonic acid release. Both propranolol and RHC-80267 markedly inhibited the ATP-induced synthesis of 6-ketoprostaglandin F1 alpha, a stable metabolite of prostacyclin. These results strongly suggest that extracellular ATP activates phosphatidylcholine-hydrolyzing phospholipase D independently of protein kinase C in aortic smooth muscle cells and that the arachidonic acid release induced by extracellular ATP is mediated, at least in part, through phosphatidylcholine hydrolysis by phospholipase D activation.
Shinoda
J
J
First Department of Internal Medicine, Nagoya University School of Medicine, Japan.
Suzuki
A
A
Oiso
Y
Y
Kozawa
O
O
D000255:Adenosine Triphosphate / Q000378:metabolism*; D000818:Animals; D001011:Aorta / Q000166:cytology / Q000378:metabolism*; D016718:Arachidonic Acid / Q000378:metabolism*; D002478:Cells, Cultured; D002794:Choline / Q000096:biosynthesis; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005110:Extracellular Space / Q000378:metabolism*; D006868:Hydrolysis; D008297:Male; D009131:Muscle, Smooth, Vascular / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D010713:Phosphatidylcholines / Q000378:metabolism*; D010739:Phospholipase D / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D019311:Staurosporine / Q000494:pharmacology
D004791:Enzyme Inhibitors; D010713:Phosphatidylcholines; D016718:Arachidonic Acid; D000255:Adenosine Triphosphate; D010739:Phospholipase D; D019311:Staurosporine; D002794:Choline