Nitric oxide stimulates prostaglandin synthesis in cultured rabbit gastric cells

Both prostaglandins (PGs) and nitric oxide (NO) have cytoprotective and hyperemic effects in the stomach. However, the effect of NO on PG synthesis in gastric mucosal cells is unclear. We examined whether sodium nitroprusside (SNP), a releaser of NO, stimulates PG synthesis in cultured rabbit gastric mucus-producing cells. These cells did not release NO themselves. Co-incubation with SNP (2 x 10(-4), 5 x 10(-4), 10(-3) M) increased PGE(2) synthesis, and SNP (10(-3) M) increased PGI(2) synthesis in these cells. Hemoglobin, a scavenger of NO, (10(-5) M) eliminated the increase in PGE(2) synthesis by SNP, but methylene blue, an inhibitor of soluble guanylate cyclase, (5 x 10(-5) M) did not affect the increase in PGE(2) synthesis by SNP. 8-bromo guanosine 3':5'-cyclic monophosphate (8-bromo cGMP), a cGMP analogue, (10(-6), 10(-5), 10(-4), 10(-3) M) did not affect PGE(2) synthesis. These findings suggest that MO increased PGE(2) and PGI(2) synthesis via a cGMP-independent pathway in cultured rabbit gastric cells. (C) 1997 by Elsevier Science Inc.