Faculty Collaboration Database

The distribution of vestibular efferent neurons receiving innervation of secondary vestibular afferent nerves in rats. Laryngoscope 2013 May;123(5):1266-71

Date

03/14/2013

Pubmed ID

23483514

DOI

10.1002/lary.23847

Scopus ID

2-s2.0-84879306998 (requires institutional sign-in at Scopus site)   13 Citations

Abstract

OBJECTIVES/HYPOTHESIS: To explore the innervation areas of the medial vestibular nucleus (MVN) afferent neurons onto vestibular efferent neurons in the brain stem of rats.

STUDY DESIGN: A morphology study in the central vestibular system.

METHODS: Two neuronal tracers were used. Lectin PHA-L Conjugates (PHA-L, Invitrogen L - 11270,) was injected into the MVN as an anterograde tracer, and 5% FluoSpheres carboxylate-modified microspheres (MFS, Molecular Probe F-8793) was injected into the contralateral peripheral vestibule using as a retrograde tracer. All animals were allowed to recover for 12 days to facilitate sufficient transportation of the tracers. Then brain stems were sliced coronally on a freezing microtome and observed under a fluorescence microscope and laser confocal microscopy.

RESULTS: Neurons in the MVN labeled with PHA-L exhibited green fluorescence, and their axons were distributed near the genu of the facial nerve (g7) and in the reticulation structure, as well as in the cerebellum or oculomotor-related nuclei. Neurons labeled with red fluorescence of MFS were mainly located dorsomedial and dorsolateral to g7 and in the caudal pontine reticular nucleus (PnC) bilaterally and presented different morphologies at different locations. The synaptic junctions would display color overlap (fluoresced yellow). Under three-dimensional reconstruction of the confocal laser microscopy, the synaptic junctions were visualized dorsomedial and dorsolateral to g7 bilaterally, predominantly ipsilateral to the MVN injection site.

CONCLUSIONS: Morphologic evidence of the distribution of vestibular efferent neurons synapsed by afferent nerves from MVN was demonstrated. These efferent neurons constitute short closed-loop circuits with neurons in the MVN.

Author List

Wang J, Chi FL, Xin Y, Regner MF

Author

Michael Regner MD Associate Professor in the Radiology department at Medical College of Wisconsin

MESH terms used to index this publication - Major topics in bold

Animals
Male
Microscopy, Confocal
Microscopy, Fluorescence
Neurons, Afferent
Neurons, Efferent
Rats
Rats, Wistar
Vestibular Nerve
Vestibular Nuclei
Vestibule, Labyrinth