Volume 60, Issue 6 pp. 790-800
Basic Science Research Article

Evaluation of the neuromuscular junction in a middle-aged mouse model of congenital myasthenic syndrome

Luana Pereira Leite Schetino MS, PhD

Luana Pereira Leite Schetino MS, PhD

Faculdade de Medicina, Universidade Federal dos Vales do Jequitinhonha e Mucuri, Diamantina, Minas Gerais, Brazil

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Matheus de Castro Fonseca MS, PhD

Matheus de Castro Fonseca MS, PhD

Laboratório Nacional de Biociências, Centro Nacional de Pesquisa em Energia e Materiais, Campinas, São Paulo, Brazil

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Matheus Proença Simão Magalhães Gomes MS, PhD

Matheus Proença Simão Magalhães Gomes MS, PhD

Departamento de Morfologia, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil

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Priscila Aparecida Costa Valadão MS, PhD

Priscila Aparecida Costa Valadão MS, PhD

Departamento de Morfologia, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil

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Wallace Lucio de Camargo MS

Wallace Lucio de Camargo MS

Departamento de Fisiologia e Biofísica, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil

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Hermann Alecsandro Rodrigues MS, PhD

Hermann Alecsandro Rodrigues MS, PhD

Departamento de Ciências Básicas da Vida, Instituto de Ciências da Vida, Universidade Federal de Juiz de Fora, Campus Governador Valadares, Minas Gerais, Brazil

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Jéssica Neves Andrade MS

Jéssica Neves Andrade MS

Departamento de Morfologia, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil

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Fernanda Magalhães Arantes-Costa MS, PhD

Fernanda Magalhães Arantes-Costa MS, PhD

Departamento de Medicina, Escola de Medicina, Universidade de São Paulo, São Paulo, São Paulo, Brazil

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Lígia Araujo Naves MS, PhD

Lígia Araujo Naves MS, PhD

Departamento de Fisiologia e Biofísica, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil

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Carla Máximo Prado PhD

Carla Máximo Prado PhD

Departmento de Biociências, Universidade Federal de São Paulo, Campus Baixada Santista, São Paulo, Brazil

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Vânia Ferreira Prado PhD

Vânia Ferreira Prado PhD

Robarts Research Institute and Department of Physiology and Pharmacology and Anatomy & Cell Biology, University of Western Ontario, London, Ontario, Canada

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Marco Antônio Máximo Prado MS, PhD

Marco Antônio Máximo Prado MS, PhD

Robarts Research Institute and Department of Physiology and Pharmacology and Anatomy & Cell Biology, University of Western Ontario, London, Ontario, Canada

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Cristina Guatimosim PhD

Corresponding Author

Cristina Guatimosim PhD

Departamento de Morfologia, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil

Correspondence

Cristina Guatimosim, Universidade Federal de Minas Gerais, Av Pres Antônio Carlos, Belo Horizonte, 6627 MG, 31270-901, Brazil.

Email: [email protected]

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First published: 18 September 2019
Citations: 4
L.P.L.S. and M.d.C.F. contributed equally to this work.

Funding information: Conselho Nacional de Desenvolvimento Científico e Tecnológico; Coordenação de Aperfeiçoamento de Pessoal de Nível Superior; Fundação de Amparo à Pesquisa do Estado de Minas Gerais; Fundação de Amparo à Pesquisa do Estado de São Paulo, Grant/Award Number: 2018/20014-0

Abstract

Introduction

Reduced expression of the vesicular acetylcholine transporter (VAChT) leads to changes in the distribution and shape of synaptic vesicles (SVs) at neuromuscular junctions (NMJs), suggesting vesicular acetylcholine (ACh) as a key component of synaptic structure and function. It is poorly understood how long-term changes in cholinergic transmission contribute to age- and disease-related degeneration in the motor system.

Methods

In this study we performed confocal imaging, electrophysiology, electron microscopy, and analyses of respiratory mechanics of the diaphragm NMJ components in 12-month-old wild-type (WT) and VAChTKDHOM mice.

Results

Diaphragms of NMJs of the VAChTKDHOM mice were similar to those in WT mice in number, colocalization, and fragmentation of pre−/postsynaptic components. However, they had increased spontaneous SV exocytosis, miniature endplate potential frequency, and diminished MEPP amplitude. No impairment in respiratory mechanics at rest was observed, probably due to the large neurotransmission safety factor of the diaphragm.

Discussion

The present findings help us to understand the consequences of reduced ACh release at the NMJs during aging.

CONFLICT OF INTEREST

The authors declare no potential conflicts of interest.

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