Plasma Norepinephrine Levels in Essential Hypertension

In 31 patients with essential hypertension there was a close relation between resting diastolic blood pressure and basal plasma norepinephrine concentrations (r = 0.741, p < 0.001). After ganglionic blockade there was a highly significant correlation between change in resting blood pressure and change in plasma norepinephrine (r = 0.813, p < 0.001). Moreover, patients with the highest resting blood pressure had the largest falls in blood pressure and plasma norepinephrine. These results suggest that the level of the blood pressure in essential hypertension is at least in part dependent on excess sympathetic activity.