Figure 4.

Bi- and three-dimensional topology of cardiac sympathetic innervation. (A) Confocal immunofluorescence of the SAN of a normal adult mouse, co-stained with antibodies to tyrosine hydroxylase (TH) and HCN4, to identify SN processes and pacemaker cells, respectively. (B) Confocal immunofluorescence imaging of ventricular myocardial section from normal adult mice, stained with antibodies to TH and cardiac troponin I (cTnI). Nuclei are counterstained with DAPI. The image is a detail from the LV subepicardial region. (C) 3-D reconstruction, at the multi-photon microscope of the sympathetic network within a portion of the LV subepicardium in an adult, Langendorff-perfused DBH-GFP heart. A segment of 230 μm by 28 μm by 50 μm was imaged. (A–C) Modified with permission from Prando et al. (2018) (A), Zaglia and Mongillo (2017) (B), and Freeman et al. (2014) (C).