Is dystrophin present in the nerve terminal nat the neuromuscular junction? An immunoshistochemical study of the heterozygote dystrophic (mdx) mouse
✍ Scribed by Johnny Huard; Louis-Philippe Fortier; Claude Labrecque; Guy Dansereau; Jacques P. Tremblay
- Publisher
- John Wiley and Sons
- Year
- 1991
- Tongue
- English
- Weight
- 813 KB
- Volume
- 7
- Category
- Article
- ISSN
- 0887-4476
No coin nor oath required. For personal study only.
✦ Synopsis
Neuromuscular junctions (NMJs) were identified by revealing the presence of cholinergic receptors (AChR) with a-bungarotoxin coupled to the fluorescent dye cascade blue in 9-and 60-day-old normal and heterozygote mdx mice. Dystrophin was detected by an immunoperoxidase technique. All the muscle fibers of the normal animals observed in cross sections were immunoreactive for dystrophin and an accumulation of dystrophin was observed at all NMJs identified by a-bungarotoxin. In the 9-day-old mdx heterozygote animals, dystrophin positive, negative, and partially positive muscle cross sections were observed. Four different observations were made in these heterozygote animals on the coexistence of AChR and dystrophin. First, a-bungarotoxin sites (i.e., NMJs) were observed on dystrophin positive muscle fiber cross sections with an accumulation of dystrophin at these sites. Second, a-bungarotoxin sites were observed on dystrophin positive fibers without a dystrophin accumulation at NMJs. Third, there was a coexistence of a-bungarotoxin and dystrophin labelling at NMJs of muscle fibers with perimeters labelling negative for dystrophin. Fourth, NMJs, identified by a-bungarotoxin, were observed on muscle fibers negative for dystrophin even at the NMJ. These observations suggest that dystrophin is present not only in the muscle membrane but also in the presynaptic nerve terminals.