angiotensin: any of several vasoconstrictor substances (trade name Hypertensin) that cause narrowing of blood vessels
vasoconstrictor: any agent that causes a narrowing of an opening of a blood vessel: cold or stress or nicotine or epinephrine or norepinephrine or angiotensin or vasopressin or certain drugs; maintains or increases blood pressure
crash barrier: a strong protective barrier that is erected around a racetrack or in the middle of a dual-lane highway in order to reduce the likelihood of severe accidents