Effect of cerebral neurite-stimulating protein on morphogenesis of organotypical culture of spinal ganglia.

We have extracted a cationic protein with a molecular weight of 15,000 kdalton from the hemispheres of rat and bovine brain. Addition of the protein to the nutrient medium of the organotypical culture of chick embryo spinal ganglia results in a considerable (2-2.5 fold) increase in the growth zone of the explants. The neurite-stimulating effect of the protein is observed at a concentration of 10 ng/ml. We observed an intensive longitudinal growth of neurites, an increase in their amount per unit area, a considerable intensification of ramification, and formation of strong anastomoses, numerous dense plexuses, and arcades. Fasciculi of neurites covered with glia are formed. The cerebral neurite-stimulating protein is evidently one of the neuron-growth factors regulating development of the nervous system in the body.