Effect of Nitric Oxide on Arachidonic Acid Release from Human Amnion-like WISH Cells

Abstract In order to clarify the possible interactions between nitric oxide (NO) and arachidonic acid (AA) pathways, human amnion-like WISH cells were perifused to measure the effects of the following substances on [ 3 H]arachidonic acid release: (1) sodium nitroprusside (SNP), a nitric oxide donor; (2) 1,1,1-trifluoromethyl-6,9,12,15-heicosatetraen-2-one, a cytosolic phospholipase A 2 (cPLA 2 ) inhibitor; (3) l -arginine, the substrate of nitric oxide synthase (NOS); (4) 3-(5′-Hydroxymethyl-2′-furyl)-1-benzylindazole and 1H-[1,2,4]oxadiazolo[4,3-α]quinoxalin-1-one, activator and inhibitor of soluble guanylyl cyclase, respectively; (5) a membrane-permeable non-hydrolyzable analogue of guanosine-3′,5′-cyclic monophosphate (cGMP). Furthermore, the effect of SNP on prostaglandin E 2 (PGE 2 ) release was tested. Exogenous and endogenous NO, as well as the guanylyl cyclase activator and cGMP analogue, significantly increased [ 3 H]arachidonic acid release. Both soluble guanylyl cyclase and PLA 2 inhibitors counteracted SNP response. Exogenous NO increased PGE 2 release, although to a much lesser degree compared with arachidonic acid release. Our results indicate that NO stimulates AA release in WISH cells by activating PLA 2 through a cyclic GMP-dependent mechanism.