Ouabain enhances nitric oxide synthesis in rat vascular smooth muscle cells induced by interleukin-1 beta

Incubation of cultured rat vascular smooth muscle cells with interleukin-1 beta caused a significant increase in the production of nitrite, a stable metabolite of nitric oxide (NO), in time- and dose-dependent manners. Addition of ouabain to the culture further enhanced interleukin-1 beta-induced nitrite production. Similarly, interleukin-1 beta produced a significant increase in the cellular level of guanosine 3',5'-cyclic monophosphate, and the increase was significantly enhanced by coincubation with ouabain. The calcium ionophore ionomycin also significantly enhanced interleukin-1 beta-induced nitrite generation. These findings indicate that ouabain enhances NO synthesis in vascular smooth muscle cells induced by interleukin-1 beta, presumably through an increase in intracellular calcium ion concentrations.