title: Ultrastructural evaluation of calcitonin gene-related peptide immunoreactivity in the human cochlea and vestibular endorgans.
abstract: Calcitonin gene-related peptide (CGRP) is a neuropeptide widely distributed in the peripheral and central nervous system. Demonstrated in the efferent systems of the mammalian cochlea and vestibule, immunoreactive patterns of CGRP may vary by species. There is, however, no information in the literature investigating CGRP localization in the human cochlea. In the present study, the ultrastructural localization of CGRP immunoreactivity was evaluated in the human inner ear with immunoelectron microscopy. It was found that, in human cochlea, CGRP immunoreactivity was located in unmyelinated nerve fibres of the spiral lamina, inner spiral fibres beneath inner hair cells, tunnel spiral fibres, tunnel crossing fibres and outer radial fibres. In endorgans of human vestibule, CGRP immunoreactivity was located in vesiculated nerve fibres and bouton-type nerve terminals which were seen to contact afferent nerve chalices surrounding type I sensory cells and afferent nerve fibres, or to form an en passant contact with afferent dendrites. CGRP immunoreactivity appeared to be confined to efferent systems in all cases. This study presents evidence that CGRP could serve a role in neurotransmission or neuroregulation in both cochlear and vestibular efferent systems of human.
authors.affiliation: Department of Otolaryngology, University of Innsbruck, Anichstrasse 35, 6020-Innsbruck, Austria.
authors.forename: Wie-Jia
authors.initials: WJ
authors.lastname: Kong
authors.forename: Arne W
authors.initials: AW
authors.lastname: Scholtz
authors.forename: Keren
authors.initials: K
authors.lastname: Kammen-Jolly
authors.forename: Rudolf
authors.initials: R
authors.lastname: Glückert
authors.forename: Burkhard
authors.initials: B
authors.lastname: Hussl
authors.forename: Paul B
authors.initials: PB
authors.lastname: von Cauvenberg
authors.forename: Anneliese
authors.initials: A
authors.lastname: Schrott-Fischer
mesh_terms: D015740:Calcitonin Gene-Related Peptide / Q000378:metabolism*; D003051:Cochlea / Q000378:metabolism* / Q000648:ultrastructure; D006199:Hair Cells, Auditory, Inner / Q000378:metabolism / Q000648:ultrastructure; D018069:Hair Cells, Vestibular / Q000378:metabolism / Q000648:ultrastructure; D006801:Humans; D007150:Immunohistochemistry; D008854:Microscopy, Electron; D009412:Nerve Fibers / Q000378:metabolism / Q000648:ultrastructure; D009475:Neurons, Afferent / Q000378:metabolism* / Q000648:ultrastructure; D017729:Presynaptic Terminals / Q000378:metabolism* / Q000648:ultrastructure; D009435:Synaptic Transmission / Q000502:physiology*; D013572:Synaptic Vesicles / Q000378:metabolism / Q000648:ultrastructure; D014722:Vestibule, Labyrinth / Q000378:metabolism* / Q000648:ultrastructure
chemical_list: D015740:Calcitonin Gene-Related Peptide