Neural Regulation of Cardiac Rhythm

The autonomic nervous system (ANS) regulates cardiac function, including chronotropy, inotropy, lusitropy, and dromotropy. The cardiac nervous system includes afferent, efferent, and interconnecting neurons, which span the intrinsic cardiac nervous system (ICNS: within the pericardium), extracardiac ganglia, and central nervous system (CNS: spinal cord and brain). This chapter focuses primarily on efferent sympathetic and parasympathetic neurotransmission and resulting end-organ (i.e., heart) electrophysiological responses. The signaling mechanisms of primary neurotransmitters are discussed, as well as the contribution of co-transmitters. Finally, several in vitro experimental models for the study of neural control of cardiac rhythm are highlighted, including key physiological findings revealed by these experimental models.