Immunocytochemical analysis of calcitonin gene-related peptide and vasoactive intestinal polypeptide in Merkel cells and cutaneous free nerve endings of cats.
Calcitonin gene-related peptide (CGRP)- and vasoactive intestinal polypeptide (VIP)-immunoreactivity were observed to coexist in Merkel cells of cats. No differences in peptide content were found between Merkel cells located in epithelia of the hard palate, in hairy and glabrous skin of the upper lip, and in vibrissae follicles. CGRP- and VIP-immunoreactive nerve fibres were also found near CGRP/VIP-immunoreactive Merkel cells. In the vibrissae follicles some CGRP- and VIP-immunoreactive nerve terminals end abutting on the glassy membrane. Other CGRP-immunoreactive nerve fibres penetrate the epithelium of the skin and end within it. Electron microscopy of vibrissae follicles revealed that Merkel cell neurites are not immunostained and that immunostained nerve fibres form unmyelinated bundles before ending freely. Thus, CGRP- and VIP-immunoreactive nerve fibres in cat skin do not end as Merkel cell neurites but as different kinds of free nerve endings.
Alvarez
F J
FJ
Neuroanatomy Department, Cajal Institute, CSIC, Madrid, Spain.
Cervantes
C
C
Villalba
R
R
Blasco
I
I
Martínez-Murillo
R
R
Polak
J M
JM
Rodrigo
J
J
D000818:Animals; D015740:Calcitonin Gene-Related Peptide; D002415:Cats; D007150:Immunohistochemistry; D009411:Nerve Endings / Q000032:analysis* / Q000276:immunology; D009412:Nerve Fibers / Q000032:analysis / Q000276:immunology; D009479:Neuropeptides / Q000032:analysis* / Q000276:immunology; D012867:Skin / Q000032:analysis* / Q000166:cytology / Q000294:innervation; D014660:Vasoactive Intestinal Peptide / Q000032:analysis* / Q000276:immunology
D009479:Neuropeptides; D014660:Vasoactive Intestinal Peptide; D015740:Calcitonin Gene-Related Peptide