TRANSFORMING GROWTH-FACTOR-BETA-2 (TGF-ETA-2) IS ASSOCIATED WITH MATURE RAT NEUROMUSCULAR-JUNCTIONS

The localisation of transforming growth factor-beta-2 (TGF-beta 2) in skeletal muscles was investigated with immunohistochemistry. In neonat es, TGF-beta 2 was distributed throughout the muscle fibres but as the fibres matured TGF-beta 2 became restricted to the circumference of a small subpopulation of nuclei. These nuclei were judged to be the sub synaptic nuclei as they lay beneath the plasmalemma and were associate d with alpha-bungarotoxin-labelled neuromuscular junctions. These obse rvations point to TGF-beta 2 being either a trophic factor for mature motoneurones or an autocrine regulator of synaptic protein production.