Figure 3

Anterograde tracer injection to the DRG specifically labeled single spinal afferent axons in myenteric ganglia of the (a) corpus and (b) antrum. (a, b) Contour of a representative corpus and antrum, respectively, and the location of a single axon within the corresponding tissue. (a’, b’) Neurolucida tracing of these axons, the innervated ganglia area (bright blue), and the non-innervated ganglia area (light orange). (a’1, a’2) Partial projection photomicrographs of red boxes in tracing (a’) displayed the single axon with “beads-on-a-string” varicosities traveling through the myenteric ganglion (a’1) and the interganglionic connectives (a’2, arrowheads). (a’1’, b’1, b’2) Higher-magnification photomicrographs of (a’1) and red boxes in tracing (b’) showed the axons traveling in close proximity to multiple neurons within the ganglia. (a’1’’, b’1’, b’2’) Single optical sections of (a’1’, b’1, b’2), respectively. The arrows point at the varicose contact of the axons on the neurons. PA = parent axon. Scale bar in (a, b) = 3 mm, in (a’, b’) = 500 μm, in (a’2) = 50 μm (also applies to a’1), in (a’1’’, b’2’) = 20 μm (also applies to a’1’, b’1, b’1', b’2).