Immunohistochemical characterisation of dorsal root ganglia neurons supplying the porcine mammary gland

The present study investigated the chemical coding of mammary gland-projecting dorsal root ganglia (DRG) neurons using double-labelling immunohistochemistry. Earlier investigations revealed the presence of Fast blue - positive (FB+) neurons in Th9-Th12 DRG after injection of the tracer into the second, right thoracic mamma. Neurons projecting to the last right abdominal mamma were found in L1-L3 DRG. In the present study, the cryostat sections from these ganglia were stained for calcitonin gene-related peptide (CGRP), substance P (SP), nitric oxide synthase (NOS), galanin (GAL) and pituitary adenylate cyclase activating polypeptide (PACAP). Immunohistochemistry revealed that the vast majority of FB+ mammary gland-projecting neurons contained immunoreactivity to CGRP (68.87±0.7%), SP (63.4±0.9%), NOS (32.47±0.9%), GAL (16.28±0.8%) and less numerous nerve cells stained for PACAP (5.87±0.5%). The present results largely correspond with findings dealing with immunohistochemical characterization of nerve fibres supplying porcine mammary gland structures described earlier.