Evidence for a critical role of the sympathetic nervous system in hypertension.

Autonomic cardiovascular control is impaired in hypertension, leading to a reduction in the parasympathetic tone and to an increase in the sympathetic influences to the heart and peripheral vessels. The sympathetic dysfunction depends on a variety of reflex and nonreflex mechanisms and participates at development and progression of the essential hypertensive state. This has been shown to be the case for borderline hypertension, for moderate and severe high blood pressure, and for resistant hypertension as well. In addition, the adrenergic overdrive participates at the pathophysiology of the complex cardiometabolic alterations, known as "end-organ damage," detectable in the clinical course of hypertensive disease. In the present article, we will review the main features of the adrenergic abnormalities characterizing essential hypertension, the mechanisms potentially involved in this neural abnormality, and its consequences as well. We will also discuss the most recent information achieved in the field and the areas worthy of future investigations.