Immunolocalization of CGRP, NPY and PGP 9.5 in guinea pig skin.

By means of immunoperoxidase and immune-alkaline phosphatase methods the immunoreactivities to neuropeptides: neuropeptide Y (NPY), calcitonin gene related peptide (CGRP) and a pan-neuronal marker, the protein gene product 9.5 (PGP 9.5), were evaluated in guinea pig deep dorsal skin specimens. CGRP immunoreactive (CGRP-IR) and NPY-immunoreactive (NPY-IR) nerve fibres were dispersed in the papillary dermis and sometimes inside the hair roots and among the sebaceous gland cells. Such localized nerve fibres have not so far been described. In the subcutaneous layer nerve trunks were found composed of CGRP-IR and NPY-IR nerve fibres. Some of these indicated vestigial or negative immunoreactivity to PGP 9.5.