Figure 1 Sympathetic and parasympathetic innervations transmit neuromodulations to the heart a: ganglion plexus; b: sympathetic nerve endings release NE to regulate myocardial activity. NTS: nucleus tractus solitarius; NA: nucleus ambiguous; CVLM: caudal ventrolateral medulla; RVLM: rostral ventrolateral medulla; SG: stellate ganglion; DRG: dorsal root ganglion; ICNS: intrinsic cardiac nervous system; GPs: ganglion plexus; NE: norepinephrine; β-AR: β-adrenergic receptor; ATP: adenosine triphosphate; AC: adenylyl cyclase; Camp: cyclic adenosine monophosphate; PKA: protein kinase A system. Adobe Illustrator CC 2021 (Adobe, San Jose, CA, USA) was used for plotting.

Figure 2 Sympathetic nerve remodeling and immunoinflammatory responses after MI A: sympathetic nerve remodeling after myocardial ischemia. a1: anatomically, sympathetic nerve remodeling is characterized by the sprouting of fiber endings in the surrounding tissues of the ischemic myocardium and denervation of the ischemic myocardium in situ. a2: functionally, sympathetic remodeling, known as electrical remodeling, is accompanied by altered electrophysiologic properties. B: immunoinflammatory response after myocardial ischemia. b1: the three overlapping immunoinflammatory response phases during MI repair and changes at the cellular level. b2: NE activates HSPC mobilization and inhibits its release into circulation by β3-AR in the bone marrow. b3: the high expression of β2-AR on splenic immune cells promotes the entry of monocytes stored in the spleen into the circulation and recruitment to the infarcted myocardium. SG: stellate ganglion; NGF: nerve growth factor; HSPCS: hematopoietic stem cell and progenitor cell. Adobe Illustrator CC 2021 (Adobe, San Jose, CA, USA) was used for plotting.

Figure 3 Acupuncture regulates cardiac function and promotes cardiac autor-epair via neuroanatomic pathways mediating somato-cardiac reflexes A: the somatic-autonomic reflex of the heart involves both the spinal and central pathways. After acupuncture at the Neiguan (PC6) acupoint in the same segment as the heart or at the Zusanli (ST36) acupoint in the nonsegmental region, the afferent information (solid black line) can trigger both central (vagus nerves, blue) and spinal (sympathetic nerves, red) reflexes. In animals with intact central nervous systems, spinal reflexes are affected by descending brain regulation (black dashed line). The spinal thoracolumbar segmental reflex is dominated by sympathetic regulation, while central descending regulation results from the sympathetic-parasympathetic balance. B: sympathetic-sensory coupling and the Neiguan (PC6)-cardiac pathway in cardiac pathology. The heart (T1-T6) has the same spinal nerve innervation as the left chest and the medial upper limb, which is due to the convergent and reverse activation of sensory information between the body surface and the viscera, which is also the most common site of cardiogenic referred pain. Stimulation of points such as Neiguan (PC6) in the same segment of the heart can activate the sympathetic nerves through the synaptic connection between the dorsal horn or directly with the sympathetic preganglionic neurons in the lateral horn, resulting in increased heart rate. C: cervical cord; T: thoracic cord; L: lumbar cord; S: sacral cord. Adobe Illustrator CC 2021 (Adobe, San Jose, CA, USA) was used for plotting.