Immunohistochemical analysis of chromogranin A and multiple peptides in the mammalian Merkel cell: further evidence for its paraneuronal function?

By the use of light microscopic immunohistochemistry, epidermal Merkel cells have been examined for the coexistence of some neuropeptides and chromogranin A (CGA). Peptide and CGA-immunophenotypes were similar in adult Merkel cells but variable in fetal skin, where CGA preceded the expression of peptides which were partly expressed only in a subpopulation of Merkel cells from hair follicles. Thus, only Substance P (SP) and calcitonin gene-related peptide (CGRP) were expressed in a subpopulation of Merkel cells from hair follicles. There were similar Merkel cell densities visualized on consecutive paraffin sections by the use of antisera against peptides, CGA and cytokeratin offering useful tools for a future systematical complementary mapping of Merkel cell populations in various species, locations and developmental stages. Electron microscopic immunohistochemistry has shown that CGA-immunoreaction is localized in the secretory granules which, again, supports the view that the Merkel cell is a paraneuron, i.e., neurosecretory in function.

Pubmed ID: 2510797 RIS Download