CGRP-IR axons and terminals in the atria.
All-in-focus projections at the regions indicated by A, B, and C in the right atrium and A1, B1, and C1 in the left atrium in Figure 1A and 1B, respectively. Detailed structure of CGRP-IR axons in different atrial regions showed similar patterns. Multiple single axon fibers formed terminal end-nets with free endings in the epicardium and myocardium. Arrows: branching points; arrow heads: free endings. Scale bar: 50μm.