Localization of brain-derived neurotrophic factor, neurotrophin-4, tropomyosin-related kinase b receptor, and p75NTR receptor by high-resolution immunohistochemistry on the adult mouse neuromuscular junction

Neurotrophins and their receptors, the trk receptor tyrosine kinases (trks) and p75NTR, are differentially expressed among the cell types that make up synapses. It is important to determine the precise location of these molecules involved in neurotransmission. Here we use immunostaining and Western blotting to study the localization and expression of neurotrophin brain-derived neurotrophic factor (BDNF) and neurotrophin-4 (NT-4) and the receptors tropomyosin-related kinase b (trkB) and p75NTR at the adult neuromuscular junction. Our confocal immunofluorescence results on the whole mounts of the mouse Levator auris longus muscle and on semithin cross-sections showed that BDNF, NT-4, trkB, and p75NTR were localized on the three cells in the neuromuscular synapse (motor axons, post-synaptic muscle and Schwann cells).