Response Characteristics of Perfused Microvessels To Pressure and Vasoactive Stimuli

Abstract

The vascular responses to vasoactive drugs was determined in isolated tissues using a method for combined perfusion and microscopic studies. A gradient of reactivity of the smaller components of the vascular bed was observed when epinephrine was delivered topically or intra-arterially, The frequency as threshold receptors in the type of muscular micro-vessels studied, precapillary, metarteriole, and arteriole, was 67%, 22%, and 11% respectively. When the distending influence of internal pressure is reduced, the microvessels regularly showed constriction or complete closure. This closure is independent of the sensitivity gradient.