TY - JOUR T1 - Simultaneous activation of adenylyl cyclase and protein kinase C induces production of nitric oxide by vascular smooth muscle cells. JF - Molecular Pharmacology JO - Mol Pharmacol SP - 274 LP - 282 VL - 46 IS - 2 AU - T Scott-Burden AU - E Elizondo AU - T Ge AU - C M Boulanger AU - P M Vanhoutte Y1 - 1994/08/01 UR - http://molpharm.aspetjournals.org/content/46/2/274.abstract N2 - 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. ER -