The sympathetic nervous system and long-term regulation of arterial pressure: What are the critical questions?

The role of the sympathetic nervous system in long-term control of arterial pressure remains unclear despite decades of intense research. Previous studies have shown that denervation of arterial baroreceptors does not chronically increase arterial pressure. As baroreceptors are thought to provide the primary 'error signal' to the autonomic nervous system, this has been interpreted as evidence against neural control of arterial pressure over long periods of time. The possibility that other 'error signals' are important in the long-term control of sympathetic activity (and arterial pressure) is introduced. The following 'Critical Questions' are presented for subsequent discussion: (i) is the sympathetic nervous system a 'major player' in the long-term control of arterial pressure; (ii) why doesn't arterial pressure remain at hypertensive levels after arterial baroreceptor denervation; and (iii) which 'error signals' are most important in the long-term control of sympathetic outflow?.