Transplantation of Xenopus laevis ears reveals the ability to form afferent and efferent connections with the spinal cord

Karen L Elliott; Bernd Fritzsch

doi:10.1387/ijdb.103061ke

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Transplantation of Xenopus laevis ears reveals the ability to form afferent and efferent connections with the spinal cord

Journal article

Open access

Peer reviewed

Transplantation of Xenopus laevis ears reveals the ability to form afferent and efferent connections with the spinal cord

Karen L Elliott and Bernd Fritzsch

The International journal of developmental biology, Vol.54(10), pp.1443-1451

2010

DOI: 10.1387/ijdb.103061ke

PMID: 21302254

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Abstract

Previous comparative and developmental studies have suggested that the cholinergic inner ear efferent system derives from developmentally redirected facial branchial motor neurons that innervate the vertebrate ear hair cells instead of striated muscle fibers. Transplantation of Xenopus laevis ears into the path of spinal motor neuron axons could show whether spinal motor neurons could reroute to innervate the hair cells as efferent fibers. Such transplantations could also reveal whether ear development could occur in a novel location including afferent and efferent connections with the spinal cord. Ears from stage 24-26 embryos were transplanted from the head to the trunk and allowed to mature to stage 46. Of 109 transplanted ears, 73 developed with otoconia. The presence of hair cells was confirmed by specific markers and by general histology of the ear, including TEM. Injections of dyes ventral to the spinal cord revealed motor innervation of hair cells. This was confirmed by immunohistochemistry and by electron microscopy structural analysis, suggesting that some motor neurons rerouted to innervate the ear. Also, injection of dyes into the spinal cord labeled vestibular ganglion cells in transplanted ears indicating that these ganglion cells connected to the spinal cord. These nerves ran together with spinal nerves innervating the muscles, suggesting that fasciculation with existing fibers is necessary. Furthermore, ear removal had little effect on development of cranial and lateral line nerves. These results indicate that the ear can develop normally, in terms of histology, in a new location, complete with efferent and afferent innervations to and from the spinal cord.

Afferent Pathways - growth & development

Ear, Inner - innervation

Motor Neurons - physiology

Hair Cells, Auditory

Ear - surgery

Spinal Cord - growth & development

Xenopus laevis

Ear - embryology

Efferent Pathways - embryology

Spinal Nerves - growth & development

Microscopy, Electron

Efferent Pathways - growth & development

Spinal Nerves - embryology

Spinal Cord - embryology

Animals

Otolithic Membrane - embryology

Afferent Pathways - embryology

Spinal Cord - physiology

Staining and Labeling

Embryo, Nonmammalian - innervation

Embryo, Nonmammalian - surgery

Ear - innervation

Details

Title: Subtitle: Transplantation of Xenopus laevis ears reveals the ability to form afferent and efferent connections with the spinal cord
Creators: Karen L Elliott - Department of Biology, University of Iowa, Iowa City, IA, USA
Bernd Fritzsch
Resource Type: Journal article
Publication Details: The International journal of developmental biology, Vol.54(10), pp.1443-1451
DOI: 10.1387/ijdb.103061ke
PMID: 21302254
NLM abbreviation: Int J Dev Biol
ISSN: 0214-6282
eISSN: 1696-3547
Publisher: Spain
Grant note: R01 DC055095590 / NIDCD NIH HHS P30 DC010362 / NIDCD NIH HHS
Language: English
Date published: 2010
Academic Unit: Iowa Neuroscience Institute; Biology; Craniofacial Anomalies Research Center
Record Identifier: 9984070894302771

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