Towards a clearer view of sympathetic innervation of cardiac and skeletal muscles.

It is well appreciated that autonomic neurons have a central role in the homeostatic regulation of organs and systems and participate to the pathogenesis of several disease conditions. As such, the function and signalling pathways activated by sympathetic neurons (SNs) in different cell types and organs have become a matter of intense investigation throughout the years of modern biomedical research. This review is focused on the methods used to address sympathetic innervation of cardiac and skeletal muscles which, quite surprisingly, has remained incompletely understood, mainly due to the technical limitations of the traditional methodologies. The current review provides a summary of the existing literature and, putting together the results obtained with different methodological approaches, provides a comprehensive view of the complexity of the SN network in striated muscles.