Sympathetic microneurography and clinical applications

The development of microneurography, in which nerve activity can be recorded directly from intraneural microelectrodes inserted into a peripheral nerve in awake human subjects, has provided a wealth of information on the control of sympathetic outflow to muscle and skin. Although not intended to be diagnostic, recordings of muscle sympathetic nerve activity (MSNA) and skin sympathetic nerve activity (SSNA) in different disease states have increased our understanding of the operation of the human sympathetic nervous system. And while quantification of sympathetic nerve activity is still largely limited to measures of burst frequency (bursts/minute) and burst incidence (bursts/100 heart beats), the development of approaches to capture the firing of single sympathetic neurones within bursts of MSNA and SSNA has provided detailed information on how the sympathetic nervous system grades its output. This chapter reviews the development of sympathetic microneurography and its application in health and disease.