Noradrenergic hyperactivity in primary hypertension; central and peripheral markers of both behavioral pathogenesis and efficacy of sympatholytic and relaxation therapy.

The effects of clonidine or relaxation therapy were determined in two separate groups of patients with primary hypertension. Ten patients were treated with clonidine monotherapy for 3 months. There were concurrent reductions of blood pressure, plasma and CSF norepinephrine, all p less than 0.01. The changes of blood pressure and norepinephrine were correlated, p less than 0.05 and 0.01, respectively. Thirty patients received hygienic instructions, and 17 of them had relaxation training in addition. Relaxation lowered blood pressures, p less than 0.01, the reduction of blood pressure was related to baseline plasma norepinephrine, p less than 0.05, and greater in patients with "raised" plasma norepinephrine, p less than 0.02. Plasma norepinephrine was lowered after hygienic therapy, p less than 0.05, the change was not significant after relaxation training. Arterial pressure elevation appears to be related to raised plasma norepinephrine. This noradrenergic hyperactivity is a marker for blood pressure responsiveness to sympatholytic therapy with clonidine or relaxation techniques.