The effects of microsurgical transection of neurite bundles in vitro before and after exposure to colchicine.

Chick dorsal root ganglia were cultured in a fluid medium. Outgrowing neurite bundles were transected with a cataract knife. Their cut ends withdrew from the site of transection and the extent of this movement was measured. Some cultures were treated with colchicine prior to transection and comparable measurements were made on them. Both proximal and distal ends of neurite bundles so treated retracted but to a lesser extent than controls. The EM appearances of control and treated groups are contrasted.