The sympathetic nervous system in the pathogenesis of hypertension

There are now numerous studies demonstrating that essential hypertension is accompanied by sympathetic activation, Using drugs which block cardiac sym pathetic effects, it could be shown that a noticeable fraction of subjects with borderline hypertension had an increased sympathetic drive, A meta-ana lysis of studies on plasma noradrenaline levels as an indirect marker of sy mpathetic tone reported that noradrenaline concentrations were significantl y elevated in patients with essential hypertension as compared with normote nsive control subjects. In addition, it could be shown that the rate of nor adrenaline spillover from sympathetic nerve terminals was sometimes increas ed in essential hypertension, particularly in young hypertensive subjects. Additional data have emerged by direct measurement of sympathetic nerve tra ffic to skeletal muscle circulation using a microelectrode technique. Most studies using this method have demonstrated increased sympathetic nerve act ivity in patients with essential hypertension, In contrast, patients with s econdary hypertension did not differ from normotensive subjects. Taken toge ther, the data available at present show that sympathetic activation is a s pecific feature of essential hypertension and that it may play a pathogenet ic role in this disease. J Hypertens 1999, 17 (suppl 3):S11-S14 (C) 1999 Li ppincott Williams & Wilkins.