["The biochemical mechanism of bile canalicular contraction is similar to that of smooth muscle contraction. Contraction follows inositol-1,4,5-trisphosphate (InsP3)-dependent Ca2+ release, which activates actin-myosin interactions. Nitric oxide is a myorelaxant through the actions of 5'-cyclic guanosine monophosphate (cGMP) and is produced in hepatocytes exposed to endotoxin and cytokines. The aim of this study was to investigate the effect of nitric oxide on canalicular contraction and to determine the mechanism by which cGMP interferes with the contractile signal.", 'The canalicular motility in rat hepatocyte doublets was measured by microscopic image analysis, and intracellular Ca2+ was measured by fluorescence microscopy. cGMP and InsP3 were determined by radio-immunoassay and high-pressure liquid chromatography. Ca2+ release from liver homogenate was measured by filtration and superfusion assays.', 'Compounds that release nitric oxide stimulated hepatocellular production of cGMP and prevented agonist-induced contraction by inhibiting the increase in intracellular Ca2+. The cGMP analogue bromo-cGMP prevented contraction and the increase in Ca2+. Bromo-cGMP marginally decreased InsP3 production. cGMP blocked InsP3-dependent Ca2+ release from internal stores.'] Does nitric oxide block bile canalicular contraction by inhibiting inositol trisphosphate-dependent calcium mobilization?