Because neuromuscular junctions tend to be localized on the central third or so of the length of a muscle (at least in mice and the muscles I use), perhaps you can induce injury to the distal thirds of the muscle without damaging the alpha-motoneurons. Because it may be hard to control the site of injury when using chemical agents, you might consider using a freeze injury like we use. To get a feel for the location of the neuromuscular junctions on a muscle, you can use fluorescently-labeled alpha-bungarotoxin. It even works well on an intact muscle, though you can only see the peripheral neuromuscular junctions. You can see them using a 4X or 5X objective on a epifluorescence microscope.

Good

Gordon L Warren Thank you a lot for your answer, it is very useful for me. What would you recommend, to try the freeze injury in tibialis or gastrocnemius muscle?

Erica Hurtado I, myself, would go with the tibialis anterior. For one, we use it all the time and we never use the gastrocnemius. Second, the attached article by Burkholder et al argues for it. Fibers are longer in the TA (see Table 1) and thus it should be easier to get away from the neuromuscular junctions when you want to induce injury. Also, the TA architecture is more fusiform in nature than is the gastrocnemius (again see Table 1). With a simpler geometry, I think that it helps make it easier to stay away from the muscle fiber regions with most of the neuromuscular junctions.