Forearm reactive hyperaemia is not mediated by nitric oxide in healthy volunteers.
OBJECTIVE
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.
Nugent
A G
AG
Department of Therapeutics and Pharmacology, The Queen's University of Belfast, Northern Ireland.
McGurk
C
C
McAuley
D
D
Maguire
S
S
Silke
B
B
Johnston
G D
GD
D000328:Adult; D000704:Analysis of Variance; D004791:Enzyme Inhibitors / Q000009:adverse effects; D005260:Female; D005542:Forearm; D006801:Humans; D006940:Hyperemia / Q000139:chemically induced / Q000209:etiology* / Q000503:physiopathology; D008297:Male; D009569:Nitric Oxide / Q000502:physiology*; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors; D012039:Regional Blood Flow / Q000187:drug effects; D019323:omega-N-Methylarginine / Q000009:adverse effects
D004791:Enzyme Inhibitors; D019323:omega-N-Methylarginine; D009569:Nitric Oxide; D019001:Nitric Oxide Synthase