active vasoconstriction

ac·tive va·so·con·stric·tion

reduction of the caliber of a vessel caused by increased tonus of smooth muscle in the vessel wall.
Farlex Partner Medical Dictionary © Farlex 2012
References in periodicals archive ?
In 1971, Mike published his first landmark paper on this topic in The Lancet [1] By employing the innovative 133Xe washout technique, Mike and colleagues clearly demonstrated for the first time that a decrease in creatinine clearance is invariably associated with significant cortical hypoperfusion, likely attributable to active vasoconstriction of the cortical vessels.
Activation of sympathetic nerves leads to active vasoconstriction, and a decrease in sympathetic activity leads to passive vasodilatation.