[Sympathy and heartache: new information on the sympathetic nervous system]

The sympathetic nervous system is an important regulator of the circulation. Interactions with other regulating systems, e.g. the renin angiotensin system, play important roles. By means of microneurography, sympathetic activity in humans can be assessed directly in the nerve. Insights into the dynamic regulation of the circulation under physiological and pathophysiological conditions are possible. Activation of the sympathetic nervous system in cardiovascular diseases affects course, prognosis, and therapy. Prognosis in heart failure depends on sympathetic activation, which can be decreased by inhibition of angiotensin II synthesis by ACE-inhibitors. In contrast to nitrates, these drugs do not increase sympathetic activity. The sympathetic nervous system is also heavily involved in the pathogenesis of hypertension. Borderline hypertensives and offspring of hypertensive parents show increased sympathetic nerve activities. Investigation of the sympathetic nervous system under physiological and pathophysiological conditions may serve as a basis for new therapeutic strategies.