NORADRENALINE SENSITIVITY IN HYPERTENSION MEASURED WITH A RADIOACTIVE SODIUM TECHNIQUE

Abstract
Radioactive Na24 was injected into the quadriceps muscle and the needle left in situ; 0.2 ml of norepinephrine was then injected through the same needle in 10 patients with normal pressure and in 20 hypertensive subjects. The mean clearance rates of Na24 in these groups did not differ significantly before norepinephrine nor was there any difference in the mean clearances of both groups after norepinephrine injection. However, the mean change in time to half value after the injection of norepinephrine was significantly greater in the hypertensive subjects. This indicates that the blood vessels of hypertensive patients have an increased sensitivity to intramuscular norepinephrine.