ACCUMULATION OF NO SYNTHASE (TYPE-1) AT THE NEUROMUSCULAR-JUNCTIONS IN ADULT MICE

RECENT data have shown that NOS-I is localized almost exclusively to t he sarcolemma of fast-twitch fibres, where it probably interacts with the dystrophin-glycoprotein complex. The concentration of dystrophin-r elated protein at the neuromuscular junctions and the possible involve ment of NO in synaptic suppression led us to investigate the presence of NOS-I at the adult motor endplates. Our data clearly show that NOS- I protein, detected by immunohistochemistry accumulates at the adult e ndplates. Furthermore, the absence of NOS-I protein at the denervated neuromuscular junctions suggest a neural origin of this enzyme. The pu tative roles of NO at the endplate are discussed.