Simultaneous activation of adenylyl cyclase and protein kinase C induces production of nitric oxide by vascular smooth muscle cells.
Rat aortic smooth muscle cells produced large quantities of nitric oxide (NO) after exposure to interleukin-1 beta, and this was depressed in the presence of the protein kinase C inhibitor bisindolylmaleimide. Intracellular cAMP levels were elevated mildly in cytokine-treated smooth muscle cells, and the presence of forskolin enhanced both the cAMP levels and NO production. Inhibition of GTP:cyclohydrolase I by 2,4-diamino-6-hydroxypyrimidine attenuated NO production by interleukin-1 beta-treated cells. GTP:cyclohydrolase is the regulatory enzyme for de novo tetrahydrobiopterin synthesis, and the latter is a required cofactor for NO synthase activity. Treatment of smooth muscle cells with forskolin induced GTP:cyclohydrolase mRNA expression, and simultaneous treatment of cells with forskolin and phorbol esters elicited NO production. Angiotensin II and arginine-vasopressin, acknowledged agonists for protein kinase C, elicited production of NO by forskolin-treated smooth muscle cells. These observations confirm the importance of GTP:cyclohydrolase activity for NO production by cultured smooth muscle cells and implicate both adenylyl cyclase and protein kinase C in this process.
Scott-Burden
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Center for Experimental Therapeutics, Baylor College of Medicine, Houston, Texas 77030.
Elizondo
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Ge
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Boulanger
C M
CM
Vanhoutte
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PM
D000262:Adenylyl Cyclases / Q000378:metabolism*; D000594:Amino Acid Oxidoreductases / Q000096:biosynthesis / Q000378:metabolism; D000818:Animals; D002478:Cells, Cultured; D005576:Colforsin / Q000494:pharmacology; D000242:Cyclic AMP / Q000494:pharmacology; D004789:Enzyme Activation; D006136:GTP Cyclohydrolase / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D015971:Gene Expression Regulation, Enzymologic; D007211:Indoles / Q000494:pharmacology; D007375:Interleukin-1 / Q000494:pharmacology; D008301:Maleimides / Q000494:pharmacology; D009131:Muscle, Smooth, Vascular / Q000166:cytology / Q000201:enzymology / Q000378:metabolism*; D009569:Nitric Oxide / Q000096:biosynthesis*; D019001:Nitric Oxide Synthase; D011493:Protein Kinase C / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D015398:Signal Transduction
D007211:Indoles; D007375:Interleukin-1; D008301:Maleimides; D012333:RNA, Messenger; D005576:Colforsin; D009569:Nitric Oxide; D000242:Cyclic AMP; D019001:Nitric Oxide Synthase; D000594:Amino Acid Oxidoreductases; D011493:Protein Kinase C; D006136:GTP Cyclohydrolase; D000262:Adenylyl Cyclases