1H-[1, 2, 4]Oxadiazolo[4, 3-a]quinoxalin-1-one(ODQ)Inhibits Cyclic GMP-PKG Pathway-Independent Nonadrenergic, Noncholinergic Relaxation in Longitudinal Muscle of the Rectum of Wistar-ST Rats

抄録

Participation of the nitric oxide-cyclic GMP pathway in nonadrenergic, noncholinergic(NANC)relaxation induced by electrical field stimulation of longitudinal muscle of the rectum of Wistar-ST rats was studied by using a selective inhibitor of soluble guanylyl cyclase, 1H-[1, 2, 4]oxadiazolo[4, 3-a]quinoxalin-1-one(ODQ).ODQ concentration dependently inhibited the relaxation and at 10μM, maximally inhibited it by 83%.However, results obtained with N^G-nitro-L-arginine, L-arginine and exogenously added nitric oxide excluded the participation of nitric oxide in the relaxation.An inhibitor of cyclic GMP-dependent protein kinase(PKG)partially(39%)inhibited the relaxation.ODQ also significantly inhibited the relaxation, which persisted after the PKG inhibitor-treatment, by 85%.The results strongly suggest that ODQ inhibits the NANC relaxation in a cyclic GMP-PKG pathway-independent manner.