CGRP-IR and SP-IR axons and terminals in the small intestine of a FVB mouse.
A, B. Single confocal optic sectioned images show CGRP-IR (Green; panel A) and SP-IR (Red; panel B) fibers and terminals in the small intestine. C. Only a few varicosities showed colocalized CGRP-IR and SP-IR in MG as yellow (arrowhead) in the composite image, whereas the majority did not. D, E. All-in-focus projection confocal images showed CGRP-IR axon terminals were mostly in MG and only a few free terminals were in the muscle layer (arrows). On the other hand, SP-IR axon networks were found richly in CM and SP-IR axon terminals were found in MG. myenteric ganglia: MG; circular muscle: CM. Scale bar in A: 50μm for A-C, in D: 50μm for D-E.