Antihistamines and vascular reactivity

Abstract

The purpose of the present set of experiments was to determine the contribution of the dilator principle, histamine, to peripheral vascular homeostasis. This was done by means of direct microscopic observation of the mesocecal microcirculation through the use of antihistamines. These drugs were found not only to produce a contraction of the microvessels but also to increase the responsiveness to topically applied cate-cholamines and antihistamines as well. The evidence does not preclude the possibility that histamine is a naturally occurring regulator of local tissue blood flow; but on the other hand, one cannot with any confidence accept this possibility.