[Ultrastructural characteristics of synaptogenesis in monolayer cultures of spinal cord].

The stages of different contact formation in monolayer cultivated cells of dissociated spinal cord and spinal ganglia from 12-14-day fetal mice were examined electronmicroscopically. The study confirmed the participation of the growth cones in the formation of different contacts. The chemical and gap junction contacts are described. It is shown that the appearance of synaptic vesicles in the growing axon precedes the membrane specialization in the area of initial contact of the axon with a target cell. The ultrastructural features of the axo-dendritic, axo-somatic and axo-axonic contacts formed de novo are presented. Desmosome participation in the formation of chemical and gap junction contacts is supposed.