Immunocytochemical localization of tetanus toxin to synapses of spinal cord

In this study, tetanus toxin was microinjected into the ventral horn of the spinal cord of rats, producing local tetanus. The toxin was localized by immunocytochemical methods. Reaction product was visualized within synaptic terminals, particularly those on the soma and dendrites of motor neurons. The distribution of staining terminals was similar to that of labeled synapses, visualized by autoradiography, after microinjection of either [125I]tetanus toxin or [3H]glycine, the latter a major inhibitor transmitter in the spinal cord.