Distribution of calcitonin gene‐related peptide at the neuromuscular junction of mdx mice

Abstract

In normal skeletal muscle, the protein dystrophin is associated with plasma membrane glycoproteins and may be involved in the stabilization of the sarcolemma. Mutant mdx mice are markedly deficient in dystrophin and show muscle fiber necrosis followed by regeneration. Changes in the distribution of acetylcholine receptors (AChRs) have been reported at the neuromuscular junction of mdx mice possibly as a result of alterations in the release or response to neural trophic factors. One such factor is calcitonin gene-related peptide (CGRP), which has been implicated in AChR synthesis and function. In this study, we used rhodamine-␣-bungarotoxin and anti-CGRP IgG FITC to study AChR and CGRP distribution at the neuromuscular junction of mdx mice. Using laser scanning fluorescence confocal microscopy, it was possible to see that CGRP-like immunoreactivity had a presynaptic distribution, covering the AChRs. Thirty-four percent of dystrophic junctions were found to be labeled with CGRP compared to 80% of control endplates. Since CGRP-positive and -negative fibers showed similar changes in AChR distribution, it is suggested that CGRP is probably not directly involved in the altered pattern of AChR seen in dystrophin-deficient muscle fibers of mdx mice.

Pre- and postsynaptic changes in the neuromuscular junction in dystrophic mice

“…The NMJ can display alterations in synaptic organization due to inactivity, denervation, aging, or crush injury to the nerve/muscle (Wilson and Deschenes, 2005 ; Jang and Van Remmen, 2011 ; Kawabuchi et al, 2011 ; Sieck et al, 2012 ). Similarly, the absence of associated proteins can cause changes in structure, and without exception, the motor endplate is noticeably disrupted in patients with DMD and mdx mice (Kong and Anderson, 1999 ; Adams et al, 2000 ; Marques et al, 2004 ; Banks et al, 2009 ; Chipman et al, 2010 ; Kulakowski et al, 2011 ).…”

A “churrascaria” of Brazilian science and biomedicine: The Anatomical Record offers a sampling from the hearty table of South America's giant in a Special Issue

“…Marques is a “frequent flyer” in The Anatomical Record , regularly publishing her most well‐respected experimental studies in muscle and neuro‐biology, particularly as it relates to neuromuscular junctions in diseased animals, including having a contribution in this Special Issue (Maciel Junior, de Carvalho, Saenz Suarez, Neto, & Marques, 2021, this issue). Studies by Marques and her team include studies on: receptors and nerve terminal distribution at neuromuscular junction of diabetic mice (Marques & Neto, 2002); calcitonin gene‐related peptides at the neuromuscular junction of MDX Mice (Marques, Guimaraes, & Neto, 2004); acetylcholine receptor organization at dystrophic neuromuscular junction of MDX mice (Marques, Taniguti, Minatel, & Neto, 2007); dystrophic extraocular neuromuscular junctions (Marques, Pertille, Carvalho, & Neto, 2007); and on fiber type composition in sternomastoid and diaphragm muscles of dystrophin‐deficient mice (Marques, Minatel, Guido, Campos, & Neto, 2010); among others. We have greatly appreciated her laboratory's frequent publications.…”

Influência da nifedipina e da coenzima Q10 no processo de degeneração/regeneração muscular em camundongos mdx

“…Fazem parte deste complexo as distroglicanas, as sintrofinas, as sarcoglicanas e as distrobevinas (para revisão ver RANDO, 2001;BIGGAR et al, 2002;LAPIDOS;KAKKAR;MCNALLY, 2004;MARQUES et al, 2004).…”