The role of endogenous nitric oxide synthesis in contractility of term or preterm human myometrium

Objective To assess in vitro the role of endogenous myometrial nitric oxide synthesis on human myometrial contraction. Design Strips of myometrium were mounted in a standard organ bath for assessment of isometric contraction and the response to modulators of nitric oxide synthesis determined. Setting A teaching hospital research laboratory. Sample Women undergoing elective nonlabour caesarean section under regional anaesthesia: 54 at term and seven preterm. Results Neither addition of L-arginine, the substrate for nitric oxide synthase, nor of an inhibitor of nitric oxide synthase led to any specific change in spontaneous myometrial contraction. Conclusion Endogenous nitric oxide production does not play an important role in the control of human term or preterm nonlabouring uterine smooth muscle contractility.