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Influence of basal nitric oxide secretion on cardiac function in man
P B Clarkson1, P O Lim, T M MacDonald
1University Department of Clinical Pharmacology, Ninewells Hospital & Medical School, Dundee, Scotland, UK.
British Journal of Clinical Pharmacology
|October 1, 1995
Summary
Basal nitric oxide synthesis in humans helps maintain vasodilation and influences cardiac diastolic function. Blocking nitric oxide with L-NMMA impacted cardiac output and diastolic filling parameters.
Area of Science:
- Cardiovascular Physiology
- Nitric Oxide Biology
Background:
- Nitric oxide (NO) is a key mediator in cardiovascular homeostasis.
- Understanding basal NO synthesis effects on cardiac function is crucial.
Purpose of the Study:
- To investigate the impact of basal nitric oxide synthesis on human cardiac function.
- To block NO synthesis using NG-monomethyl-L-arginine (L-NMMA) and assess cardiovascular responses.
Main Methods:
- Eight healthy volunteers participated in a placebo-controlled study.
- Incremental infusion of L-NMMA or placebo was administered.
- Cardiac function was assessed using heart rate, blood pressure, and echocardiography.
Main Results:
- L-NMMA infusion increased systolic blood pressure and systemic vascular resistance.
- Significant reductions in stroke distance and cardiac index were observed.
- Isovolumic relaxation time increased, indicating impaired diastolic function.
Conclusions:
- Basal nitric oxide generation in humans promotes vasodilation.
- NO significantly influences left ventricular diastolic filling parameters.
- Inhibition of NO synthesis affects cardiac output and vascular tone.
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