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Forearm reactive hyperaemia is not mediated by nitric oxide in healthy volunteers
A G Nugent1, C McGurk, D McAuley
1Department of Therapeutics and Pharmacology, The Queen's University of Belfast, Northern Ireland.
Aims:
To determine the role of nitric oxide (NO) in forearm reactive hyperaemia in healthy human subjects.
Methods:
Ten healthy subjects aged 19-34 years underwent brachial artery cannulation. Forearm circulatory arrest was achieved by means of an upper arm cuff inflated to 200 mmHg for 5 min. The blood flow responses during reactive hyperaemia were measured using venous occlusion plethysmography following a 10 min intra-arterial infusion of 8 micromol min-1 N-monomethyl L-arginine (L-NMMA) and following matching placebo administered in random order. Results were analysed by repeated measures anova and t-tests.
Results:
L-NMMA resulted in a significant reduction of basal forearm blood flow indicating inhibition of basal NO release (P=0.005). There was no significant difference between the blood flow responses during reactive hyperaemia following L-NMMA and placebo (P=0.97).
Conclusions:
Nitric oxide production does not make a significant contribution to the vasodilatation associated with reactive hyperaemia in the human forearm.