Sympathetic activation decreases medium-sized arterial compliance in humans

Abstract

This study used a precise noninvasive method in normotensive humans to determine the effects of sympathetic activation on arterial compliance. A recently developed, high-resolution echo-tracking system capable of measuring systolic/diastolic variations of arterial diameter was coupled to a Finapres system and used to calculate instantaneous systolic/diastolic pressure-diameter and compliance-pressure curves for a muscular medium-sized artery, the radial artery. Two standardized tests of sympathetic system activation, a cold pressor test (2 min) and a mental stress test (2 min of mental arithmetic), were performed at an interval of 8 days in random order in nine healthy volunteers [30 +/- 9 (SD) yr]. Radial arterial parameters were recorded every 30 s for 9 min, which included 2 min of cold pressor test or mental stress test. During both tests, radial arterial mean diameter did not change despite t he increase in mean arterial pressure (P < 0.001); stroke change in diameter decreased (P < 0.01), whereas pulse pressure increased (P < 0.01). Arterial compliance, calculated for the instantaneous level of mean arterial pressure, decreased significantly (P < 0.01). Compliance (C) calculated at 100 mmHg (C100) was arbitrarily chosen as a reference point for comparing compliance among the different periods of the test. C100 decreased significant (P < 0.05) during both tests (from 2.93 +/- 1.27 to 2.04 +/- 0.94 and from 3.29 +/- 1.73 to 2.63 +/- 1.55 mm2.mmHg-1.10(-3) during mental stress and the cold pressor test, respectively). These results indicate that sympathetic activation is able to decrease radial arterial compliance in healthy subjects. The reduction in arterial compliance probably resulted from complex interactions between changes in distending blood pressure and changes in radial arterial smooth muscle tone.

Acute effects of cardiac resynchronization therapy on arterial distensibility and serum norepinephrine levels in advanced heart failure

“…Activation of the sympathetic nervous system has been shown to reduce distensibility of small-and medium-size arteries in animals [30,31]. Also, one study demonstrated that increases in sympathetic stimulation are associated with the reduction of radial artery distensibility in humans [33]. The sympathetic nervous system exerts a marked tonic restraint on large arterial distensibility, and this restraint involves large arteries with a predominant elastic structure and arteries with a predominant muscle structure.…”

Interactive Effect of Heart Rate and Muscle Sympathetic Nerve Activity on Blood Pressure

“…Sympathetic activation during the cold-pressor test or mental stress decreases radial arterial compliance and increases SBP and pulse pressure. 26 The sympathetic nervous system may also contribute to blood pressure levels in the long term by mechanisms other than its effect on vasomotor tone, such as by its effects on the kidney. 27 Wallin et al 28 have demonstrated that in healthy human subjects, resting sympathetic nerve traffic is proportional in sympathetic nerves to both muscle blood vessels and the kidney.…”

Exercise training favourably affects autonomic and blood pressure responses during mental and physical stressors in African-American men

“…20,50,51 Arterial compliance Loss of AC during sympathetic stimuli leads to exaggerated increases in an a 2 -adrenergic-mediated vasoconstriction and/or decreases in b 2 -adrenergicmediated vasodilation, both of which contribute to increases in arterial stiffness. Augmented and/or exaggerated sympathetic activity has been shown to further reduce distensibility of small, medium and large arteries, [49][50][51][52][53] and is a common denominator for risk factors related to hypertension. [54][55][56] Our prior study, and that of others, has shown that a strong relationship exists between .…”