Immunohistochemical characteristics of cutaneous Herbst corpuscles from beak and rictus in domestic pigeon.
Herbst corpuscles are the avian equivalent to the mammalian Pacinian corpuscles. In this study we used indirect peroxidase-anti peroxidase (PAP) immunohistochemistry to analyze the distribution in the pigeon cutaneous Herbst corpuscles, of several markers which are known to specifically label the axon, the Schwann-related and perineurial-related cells in Pacinian corpuscles. The distribution of the assessed antigens on Herbst corpuscles was as follows: i) the central axon displayed positive immunoreactivity for neurofilament proteins and neuron specific enolase; ii) the lamellar cells forming the inner-core were positive for S-100 protein and vimentin, whereas fibroblast surrounding them were vimentin and epithelial membrane antigen positive; iii) the capsule was focally immunolabelled for vimentin, and regularly for epithelial membrane antigen. No immunoreactivity was found neither for cytokeratins nor for glial fibrillary acidic protein. These observations demonstrate that the immunohistochemical profile of cutaneous (beak skin and rictus) Herbst corpuscles in pigeon is similar to that of the mammalian Pacinian corpuscles.