Control of tone in vascular smooth muscle.

• Total peripheral resistance and regional blood flow are determined by the contractile activity of vascular smooth muscle cells. The control systems that determine the activity of arterial smooth muscle are described. The interactions among control systems that underlie the remarkable diversity In the responses of blood vessels are emphasized to illustrate how various classes of drugs mediate clinically important effects. ( Arch Intern Med 1983;143:1001-1006)