VARIATIONS OF VASCULAR REACTIVITY IN NORMAL AND HYPERTENSIVE DOGS

Abstract

The response of the vessels to chemical stimuli as measured by arterial blood pressure change was studied in 722 dogs. It was found to change during the same expt. and on different days. There was no direct relationship between the response to one drug compared with another, though often they paralleled one another. Nor was it a function of the height of the blood pressure, wt., temperament, length of kennel residence, depth of anesthesia, temp., voluntary muscle relaxation, or intra-arterially admn. salt solution. Neither early nor late after eliciting renal hypertension does the vascular reactivity to epinephrine, nicotine, histamine, barium chloride, angiotonin, renin or tetraethyl ammonium chloride change in a characteristic fashion as to suggest the dominance of either the nervous system or a humor mechanism in the production or maintenance of hypertension.