Nitric oxide (NO) is known to influence muscular conduit artery pulse wave velocity (PWV). Whether these changes are mediated exclusively by NO or may be a general consequence of a change in arterial tone is unknown. The aim of this study was to examine changes in local PWV over a range of arterial tone modulated by vasoconstrictor/dilator drugs. Healthy normotensive men (n=7) aged 19–53 years were studied. The right brachial artery was cannulated using a 27 gauge needle. Nitroglycerin (NTG 0.03, 0.1, 0.3, 1 μg/min), phentolamine (PHT 10, 30,100 μg/min) and (NE 0.01, 0.02, 0.04 μg/min) alone and with PHT (100 μg/min) were infused intra-arterially on separate occasions. Radial artery diameter (RAD) was measured by high resolution ultrasound; PWV was measured over the brachial to radial path by simultaneous recording from brachial and radial blood pressure cuffs inflated to 60 mmHg. The path distance was taken from the proximal edge of the upper arm cuff to that of the wrist cuff. NE (0.04 μg/min) reduced RAD by 11.4±4.1% but when co-infused with PHT (100 μg/min) increased RAD by 5.8±3.5%. NTG (1 μg/min) increased RAD by (32.1±5.4%). Over this range of arterial tone, changes in PWV were closely related to those in RAD (figure, R= −0.89; P<0.05). This suggests that, under physiological conditions, PWV in muscular arteries is determined by smooth muscle tone rather than being influenced by a specific signalling pathway.