Does sympathetic activity, as measured by plasma norepinephrine levels and response to ganglionic blockade, correlate with blood pressure in patients with essential hypertension?
Blood pressure levels in essential hypertension strongly correlate with plasma norepinephrine both at rest and after ganglionic blockade, suggesting that excess sympathetic activity contributes to the condition.
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.
Louis et al. (1973) studied this question.