The effect of tetanus toxin on in vitro synaptogenesis.

Cultures of spinal cord neurons and cocultures of rat embryo neurons and muscle cells have been studied in the presence of tetanus toxin (TT) at a concentration of 40 micrograms/ml of medium. TT strongly stimulated neurite outgrowth, notably branching from the cell bodies. In addition it induced a marked, overall increase in acetylcholine receptor (AChR), but inhibited focalisation of AChR and acetylcholinesterase (AChE) at the synaptic sites. TT seems to act on neurite emergence, on the neuronal factor(s) controlling AChE and AChR concentrations, and on the factor(s) modulating degradation and/or synthesis of AChR.