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Merkel cells, a new localization of prepro‐orexin and orexin receptors
Author(s) -
BeirasFernández Andrés,
Gallego Rosalía,
Blanco Montserrat,
GarcíaCaballero Tomás,
Diéguez Carlos,
Beiras Andrés
Publication year - 2004
Publication title -
journal of anatomy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.932
H-Index - 118
eISSN - 1469-7580
pISSN - 0021-8782
DOI - 10.1111/j.1469-7580.2004.00266.x
Subject(s) - orexin , merkel cell , biology , receptor , orexin receptor , enteroendocrine cell , orexin a , epidermis (zoology) , lateral hypothalamus , medicine , microbiology and biotechnology , endocrinology , neuropeptide , hypothalamus , merkel cell carcinoma , anatomy , endocrine system , biochemistry , genetics , carcinoma , hormone
Orexins (OXA and OXB) are peptides derived from a common precursor called prepro‐orexin. They act through G‐protein receptors named orexin 1 receptor (OX 1 R) and orexin 2 receptor (OX 2 R). Orexins were first demonstrated in neurons of the lateral hypothalamus and found to be related to the control of food intake. However, it has been shown that they are widely distributed in both the nervous system and peripheral tissues, including endocrine organs such as the pituitary and adrenal glands. Merkel cells are neuroendocrine cells situated in the epidermis, tactile hairs and oral mucosa, and act as mechanoreceptors. Up to the present, various neuropeptides have been detected in these cells. The aim of the present study was to detect the presence of prepro‐orexin and orexin receptors (OX 1 R and OX 2 R) in porcine Merkel cells using immunohistochemistry. Prepro‐orexin was expressed in the cytoplasm of Merkel cells in the skin of the pig snout. Immunoreactivity for prepro‐orexin was more intense in the mature side of the cell, where the dense‐cored granules are accumulated. Epidermal nerve terminals associated with Merkel cells and dermal nerve fibres showed no immunostaining. Both orexin receptors (OX 1 R and OX 2 R) were also demonstrated in the cytoplasm of Merkel cells of pig snout skin. The finding of orexins and their receptors in Merkel cells suggests that they have an autocrine function. Further studies are needed to ascertain the significance of this function.