Growth cone formation in cultures of sensory neurons.

Abstract

Three experimental situations were found in which cultured sensory neurons from embryonic chicken formed growth cones from positions along the length of the neurite. If the neurons were dissected with a remaining short axonal stump and plated into serum-free medium, they formed a morphologically normal growth cone from the stump within 15 min, even in the presence of cycloheximide or puromycin. When neurites growing in culture media with low levels of serum were cut at any point with microneedles, growth cones were produced quickly from the amputated stump, usually within 20 min. Treatment of growing neurons with low concentrations of colchicine, Colcemid or podophyllotoxin resulted in the progressive appearance of lateral filopodia and regions of flattened cytoplasm that closely resembled growth cones except for their preterminal positions. Apparently, the potential to form growth cones is distributed throughout the neuron and this is normally repressed in some way by the neuronal microtubules.