title: Phorbol ester-induced phosphoinositide hydrolysis in rat aorta: role of cyclooxygenase products.
abstract: This study investigates whether phorbol esters increase phosphoinositide hydrolysis in intact vascular smooth muscle, and the mechanism underlying the hydrolysis. Phorbol myristate acetate induced time- and concentration-dependent increases in phosphoinositide hydrolysis, as demonstrated by elevated inositol monophosphate levels, in deendothelialized rat aorta. The phorbol ester-elevated inositol monophosphate levels were abolished by indomethacin, a cyclooxygenase inhibitor, but were only partially decreased by SQ29548, a thromboxane A2/prostaglandin H2 receptor antagonist. SQ29548 also only partially decreased elevated inositol monophosphate levels due to prostaglandin E2, prostaglandin F2alpha, prostaglandin I2 and carbacyclin, a stable prostaglandin I2 analog. SQ29548 abolished elevated inositol monophosphate levels due to U46619, a stable thromboxane A2/prostaglandin H2 receptor agonist. These studies demonstrate that phorbol esters increase phosphoinositide hydrolysis in intact vascular smooth muscle, and that the increase is due, at lease in part, to endogenously released prostaglandins other than prostaglandin H2.
authors.affiliation: Department of Pharmacology and Cell Biophysics, University of Cincinnati College of Medicine, OH 45267-0575, USA. robert.rapoport@uc.edu
authors.forename: R M
authors.initials: RM
authors.lastname: Rapoport
authors.forename: S P
authors.initials: SP
authors.lastname: Williams
authors.forename: A K
authors.initials: AK
authors.lastname: Campbell
mesh_terms: D019796:15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid / Q000494:pharmacology; D000818:Animals; D001013:Aorta, Thoracic / Q000187:drug effects* / Q000201:enzymology; D019086:Bridged Bicyclo Compounds, Heterocyclic; D011464:Epoprostenol / Q000031:analogs & derivatives* / Q000494:pharmacology; D005231:Fatty Acids, Unsaturated; D006834:Hydrazines / Q000494:pharmacology; D006868:Hydrolysis; D007213:Indomethacin / Q000494:pharmacology; D007295:Inositol Phosphates / Q000378:metabolism; D009131:Muscle, Smooth, Vascular / Q000187:drug effects* / Q000201:enzymology; D010716:Phosphatidylinositols / Q000378:metabolism*; D011451:Prostaglandin-Endoperoxide Synthases / Q000378:metabolism*; D011453:Prostaglandins / Q000378:metabolism* / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D015398:Signal Transduction / Q000187:drug effects; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology*
chemical_list: D019086:Bridged Bicyclo Compounds, Heterocyclic; D005231:Fatty Acids, Unsaturated; D006834:Hydrazines; D007295:Inositol Phosphates; D010716:Phosphatidylinositols; D011453:Prostaglandins; C026678:carboprostacyclin; D019796:15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid; C045749:SQ 29548; D011464:Epoprostenol; D011451:Prostaglandin-Endoperoxide Synthases; D013755:Tetradecanoylphorbol Acetate; D007213:Indomethacin