NOS Uncoupling Evokes Oxidative Stress and the Cardiohemodynamic Disorders in Hypertension

Abstract

We compared cardiohemodynamic parameters and indicators of oxidative and nitrosative stress in the heart and the aorta of normotensive Wistar rats (WKR) and spontaneously hypertensive rats (SHR). Based on the experimental data, cNOS uncoupling index and biochemical index of cardiac and vascular function (BIF) were calculated. In the heart, and especially in the aorta of the SHR, a combined oxidative and nitrosative stress develops that leads to cNOS uncoupling, a decrease in BIF that correlates with reduced systolic and diastolic functions, as well as an inhibition of Frank-Starling mechanism, reduction of oxygen consumption of the heart and increased arterial stiffness. We suggest that there is the vicious circle of mutual reinforcement of oxidative stress and cNOS uncoupling due to excessive superoxide generation in the organs of the cardiovascular system in hypertension, which may by the reason for worsening of cardiohemodynamics.