The behaviour of the flow-mediated brachial artery vasodilatation during orthostatic stress in normal man

• Published in: Acta physiologica Scandinavica 2004-12, Vol.182 (4), p.353-360
• Main Authors: Guazzi, M., Lenatti, L., Tumminello, G., Puppa, S., Fiorentini, C., Guazzi, M. D.
• Format: Article
• Language: English
• Subjects: Adult; autonomic nervous system; Biological and medical sciences; Blood vessels and receptors; Brachial Artery - diagnostic imaging; Brachial Artery - physiology; endothelium; Endothelium, Vascular - physiology; Forearm - blood supply; Fundamental and applied biological sciences. Psychology; head-up tilting; Humans; Male; Nitroglycerin - pharmacology; Posture - physiology; Regional Blood Flow; Supine Position - physiology; Tourniquets; Ultrasonography, Doppler, Pulsed; vasodilatation; Vasodilation - drug effects; Vasodilation - physiology; Vasodilator Agents - pharmacology; Vertebrates: cardiovascular system
• ISSN: 0001-6772; 1365-201X
• DOI: 10.1111/j.1365-201X.2004.01365.x

Aims:  Flow‐mediated brachial artery vasodilatation is an index of endothelial function. Published literature describes only supine data and no study has been performed during vertical displacement. This subject deserves investigation for two main reasons: humans spend the larger part of their life in the upright position; this position has significant effects on neural vascular regulation. Methods:  In 21 healthy men (25 ± 2 years) the flow‐dependent brachial artery vasodilating response to distal circulatory arrest was assessed by Doppler ultrasound imaging, while supine and during 20° and 60° head‐up tilting (HUT). In 11 of these subjects the vasodilating response to nitroglycerine was also explored. Results:  Absolute and percentage increments in brachial calibre during hyperaemia after deflation of the occluding cuff became increasingly greater at 20° (+0.44 mm) and 60° (+0.92 mm) HUT (P