Pigeon as a model to study peripheral projections from the horizontal semicircular canal vestibular apparatus to a brainstem target immunoreactive for AMPA.

João Roberto Rocha,Ana Lúcia Beirão Cabral,Claudio Antônio Barbosa De Toledo,Marcia Koike,Julianne Dos Santos Maldonado-Menetti,Maria De Fátima Passetto

doi:10.1590/acb361206

João Roberto Rocha, Ana Lúcia Beirão Cabral + Show 4 more

Open Access

https://doi.org/10.1590/acb361206

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Abstract

ABSTRACTPurpose:To evaluate whether the pigeon (Columba livia) is a good model for evaluating the vestibular system involved with postural maintenance during movement.Methods:This study maps the brainstem targets of the horizontal ampullary inputs from the vestibular periphery of the pigeon. We used biotin dextran amine (BDA) injection in horizontal semicircular canal (HSCC), immunohistochemistry for GluR2/3 and GluR4 AMPA and computerized histomorphology reconstruction.Results:Our results show the same distribution pattern with ipsilateral projections to vestibular nuclear complex (VNC) from the HSCC, with the majority of labeled fibers being, long, thin, with few varicosities and many ramifications. Horizontal semicircular canal projections achieve neurons belonging to all nuclei of the VNC with exception of dorsal portion of lateral vestibular nucleus and this area express GluR2/3 and GluR4 AMPA receptors reinforcing the idea of glutamate participation in these connections.Conclusions:Pigeon is an appropriated experimental model to study of projections of HSCC and reinforcing the information that the vestibular system has strong relation with the fast responses necessary for postural control. Moreover, its phylogenetic organization apparently conservation, also seems to be a fundamental characteristic for vertebrates.

Highlights

Maintaining the equilibrium and to provide postural adjustment in face with the gravity force is a fundamental requirement of all vertebrate species
Our results show the same distribution pattern with ipsilateral projections to vestibular nuclear complex (VNC) from the horizontal semicircular canal (HSCC), with the majority of labeled fibers being, long, thin, with few varicosities and many ramifications
Horizontal semicircular canal projections achieve neurons belonging to all nuclei of the VNC with exception of dorsal portion of lateral vestibular nucleus and this area express GluR2/3 and GluR4 AMPA receptors reinforcing the idea of glutamate participation in these connections

Summary

Introduction

Maintaining the equilibrium and to provide postural adjustment in face with the gravity force is a fundamental requirement of all vertebrate species. The vestibular inputs of vertebrates come from the ampullae’s and macula’s hair cells present in the cupula of the semicircular canals (ampullary crista) and in the interior of the sacculus and the utricle (saccular macula and utricular macula), respectively[4,9,10]. Those hair cells are innervated by glutamic acid vestibular bipolar neurons in which perikarya are in the vestibular nerve ganglion (formally the Scarpa’s ganglion). While many pharmacological properties are familiar[12,13,18,19,20] the morphological details of its circuitry remain unknown

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