Cutaneous Merkel cells of the rat contain both dynorphin A and vesicular monoamine transporter type 1 (VMAT1) immunoreactivity

Autor: E, Weihe, W, Hartschuh, M K, Schäfer, H, Romeo, L E, Eiden
Rok vydání: 1998
Předmět:
Zdroj: Canadian Journal of Physiology and Pharmacology. 76:334-339
ISSN: 1205-7541
0008-4212
DOI: 10.1139/y98-032
Popis: To delineate fully opioid peptide function in cutaneous inflammatory and nociceptive responses, it is necessary to know first which opioid peptides are present in the skin and which cellular elements in the skin store and secrete them. Merkel cells are cutaneous neuroendocrine cells, which may derive from the neural crest or from undifferentiated keratinocytes with stem cell character. The neuroendocrine character of Merkel cells is supported by their immunoreactivity for chromogranin A (CGA) and a variety of neuropeptides, among them the opioid peptide [Met]enkephalin as shown in guinea-pig and mouse. This study investigates in the rat whether the preprodynorphin derived opioid peptide dynorphin A is expressed in cutaneous Merkel cells and possibly related to an aminergic phenotype. Light microscopic immunohistochemistry revealed dynorphin A immunoreactivity in Merkel cells to be codistributed with immunoreactivity for calcitonin gene-related peptide (CGRP) and CGA, two well-established marker peptides of mammalian Merkel cells. Vibrissal Merkel cells stained for the neuroendocrine vesicular monoamine transporter isoform 1 (VMAT1) but not for the predominantly neuronal isoform 2 (VMAT2). Merkel cell staining for dynorphin A, VMAT1, CGA, and CGRP was unaffected by experimental denervation. Dynorphin A and a still unidentified monoamine, possibly serotonin, may cofunction as autocrine or paracrine mediators in the mechanosensory Merkel cell - axon complex and are potentially involved in peripheral analgesia.Key words: skin, opioid, neuropeptide, neuroendocrine, pain.
Databáze: OpenAIRE