Plasma detection of NO by a catheter.

Nitric oxide (NO) released by endothelial cells in response to hemodynamic shear stress is a key controller molecule of the vascular functions and antiatherogenic mechanisms. Endothelial dysfunction is associated with increased cardiovascular events. Therefore, several indirect techniques have been employed to evaluate endothelial function or NO bioavailability. However, a growing body of evidences suggests limitations of the indirect methods for evaluation of NO bioavailability. In years, it has been considered that NO is immediately oxidized or inactivated in blood stream. However, recent studies suggest that NO remain active in blood stream, causing remote biological response. Therefore, measuring plasma NO concentration directly in the circulation will contribute to clarify the kinetics and physiological roles of NO and to evaluate endothelial function. In this article, the measurement of plasma NO concentration using a newly developed catheter-type NO sensor will be described.