PRESYNAPTIC LOCALIZATION OF OMEGA-CONOTOXIN-SENSITIVE CALCIUM CHANNELS AT THE FROG NEUROMUSCULAR-JUNCTION

By the use of anti-omega-CTx antibodies in indirect immunofluorescence we demonstrated the presence of omega-CTx binding sites in the presynaptic compartment of frog nerve-muscle preparations. The images we obtained indicate that omega-CTx-sensitive channels are clustered at discrete sites corresponding in distribution to active zones.