Divergent effects of ACE-inhibition and calcium channel blockade on NO-activity in systemic and renal circulation in essential hypertension

Abstract

These results indicate that, in essential hypertensives, antihypertensive therapy with enalapril or nifedipine increases nitric oxide dependency of systemic vascular tone, which may play a role in the blood pressure lowering effect of these drugs. However, this phenomenon cannot be observed in the renal circulation, suggesting a different regulation of endothelium-dependent vasomotion in the hypertensive kidney.

An 18oxygen inhalation method for determination of total body formation of nitric oxide in humans

“…The administration of L ‐NMMA did, however, as mentioned above, cause an increase in blood pressure, indicating that NO formation was in fact inhibited. A similar increase in blood pressure has been reported previously ( Dijkhorst‐Oei et al ., 1998 ). The administration of L ‐NMMA was also followed by a decrease in NO formation, to less than half of that observed in the absence of drug.…”

The Effects of Losartan and Enalapril Therapies on the Levels of Nitric Oxide, Malondialdehyde, and Glutathione in Patients with Essential Hypertension.

“…However, enhanced degradation of NO by increasing ROS along with reducing NO bioviability in the vascular wall have also been demonstraeted. In some studies, it has been shown that plasma NO levels increased with ACE inhibitor [4,28,29] as well as calcium channel blocker therapy [30]. In our study, NO levels in the exhaled air of hypertensive patients rose after treatment, but it is not clear whether or not this increase was due to endogenous NO production.…”

Interaction of Endothelial Nitric Oxide and Angiotensin in the Circulation

“…In patients with essential hypertension, intravenously infused L-NMMA increased mean arterial pressure and systemic vascular resistance, whereas cardiac output was decreased; enalapril decreased blood pressure, whereas the L-NMMA-induced increase in systemic vascular resistance was potentiated by ACE inhibition, indicating that antihypertensive therapy with enalapril increases NO dependence of systemic vascular tone (Dijkhorst-Oei et al, 1998). Antihypertensive therapy with enalapril seems to increase the NO dependence of systemic vascular tone; however, this phenomenon cannot be observed in the renal circulation.…”