The effects of pentolinium on sympathetic activity in hypertensives and normotensive controls

The effects of pentolinium tartrate 2.5 mg i.v. on blood pressure, heart rate and plasma noradrenaline and adrenaline concentrations were studied in 21 hypertensives and in 20 normal controls. Mean basal catecholamine concentrations and the extent of their suppression by pentolinium were similar in both groups. The reductions in both plasma catecholamine levels correlated with the prepentolinium values. Supine systolic blood pressure was significantly reduced and there was a small increase in heart rate. These data support the use of plasma noradrenaline as an index of sympathetic activity but are inconsistent with the hypothesis that essential hypertension is associated with hyperactivity of the sympathetic nervous system.