cyclic-gmp and 1-nitro-2-phenylethane

The nitroderivative 1-nitro-2-phenylethane (NPE) was recently described as a compound possessing heme-dependent soluble guanylyl cyclase (sGC) stimulating properties in vascular smooth muscle cells. In this study, we tested such pharmacological property of NPE in mice pancreatic acinar cells subjected to the bile salt taurocholate, a type of pathological stimulus that simulates pancreatitis. Here, isolated acinar cells were treated with NPE in order to assess the role of sGC on the detrimental effects induced by taurocholate. NPE reduced taurocholate-elicited Ca(2+) overload, production of reactive oxygen species (ROS), apoptosis, necrosis, and exerted a protective effect against mitochondrial membrane potential (ΔΨm) dissipation. These NPE-induced effects were abolished by pretreatment with ODQ and KT 5823, and after the blockade of nitric oxide (NO) synthase with l-NAME, inhibitors of key components of the sGC pathway. Contrarily to cGMP that alone increased ΔΨm collapse and cell damage, the cytoprotective effect of NPE on ΔΨm and cell necrosis was almost reproduced by 8-nitro-cGMP, a second messenger generated by sGC under oxidative stress conditions. In conclusion, putative sGC stimulation with NPE reveals its cytoprotective profile on pancreatic cells subjected to taurocholate. Moreover, ROS and NO conjunctly appear to drive sGC activity in pancreatic acinar cells to implement an adaptive mechanism in response to oxidative and Ca(2+) stress through 8-nitro-cGMPsynthesis.

Topics: Acinar Cells; Animals; Apoptosis; Benzene Derivatives; Calcium Signaling; Cells, Cultured; Cyclic GMP; Male; Mice; Necrosis; Pancreas; Reactive Oxygen Species; Taurocholic Acid

1-Nitro-2-phenylethane is the first organic NO₂-containing molecule isolated from plants. It possesses interesting hypotensive, bradycardic, and vasodilator properties, but the mode by which it induces vasorelaxation is still unknown. The underlying mechanism involved in the vasodilator effect of 1-nitro-2-phenylethane was investigated in rat aorta. The vasorelaxant effects of 1-nitro-2-phenylethane did not depend on endothelial layer integrity, and the effects were refractory to L-N(G)-nitroarginine methyl ester (L-NAME)-induced nitric oxide synthase inhibition. Vasorelaxation was similarly resistant to treatment with indomethacin, cis-N-(2-phenylcyclopentyl)-azacyclotridec-1-en-2-amine hydrochloride (MDL-12330A), and KT5720, indicating that neither prostaglandin release nor adenylyl cyclase activation is involved. Conversely, methylene blue- and ODQ-induced guanylate cyclase inhibition reduced the vasorelaxation induced by 1-nitro-2-phenylethane. The pharmacological blockade of K(+) channels with tetraethylammonium, glybenclamide, and 4-aminopyridine also blunted vasorelaxation induced by 1-nitro-2-phenylethane. The effects of 1-nitro-2-phenylethane were reversed by 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (ODQ) and comparable to the effects induced by sodium nitroprusside. In silico analysis using an Ns H-NOX subunit of guanylate cyclase revealed a pocket on the macromolecule surface where 1-nitro-2-phenylethane preferentially docked. In vitro, 1-nitro-2-phenylethane increased cyclic guanosine 3',5'-monophosphate (cGMP) levels in rat aortic rings, an effect also reversed by ODQ. In conclusion, 1-nitro-2-phenylethane produces vasodilator effects by stimulating the soluble guanylate cyclase-cGMP pathway.

Topics: Animals; Benzene Derivatives; Cyclic GMP; Guanylate Cyclase; Male; Rats; Rats, Wistar; Receptors, Cytoplasmic and Nuclear; Soluble Guanylyl Cyclase; Vasodilator Agents