Single fiber analysis of muscle sympathetic nerve activity

Abstract

Direct recording of multiunit efferent muscle sympathetic nerve activity (MSNA) by microneurography is the best method for quantifying sympathetic nerve activity in humans. It has been still recognized as a gold standard method for evaluation of sympathetic nerve activity in human. Recently, single-unit MSNA analysis was developed in humans. Single-unit MSNA reveals (1) firing frequency of single-unit MSNA, (2) multiple firing of single-unit MSNA within one cardiac interval, and (3) functionally different neuron activities, which could not be obtained by multiunit MSNA analysis. Single-unit MSNA provides additional information regarding actual sympathetic neuron firing to peripheral. Several studies have already demonstrated that single-unit MSNA analysis shed insight into the mechanism of actual central sympathetic firing to peripheral in several cardiovascular diseases. In this chapter, we describe the differences between analysis of multiunit and single-unit MSNA and discuss the advantages of single-unit MSNA recording.