The Degree of Specificity of Synaptic Contacts during Neurotransplantation

Abstract

Transplantation of immature nerve tissue is a promising biotechnological approach to repair damaged brain tissue. The success of transplantation therapy depends on a genetic program for the differentiation of donor neuronal precursors and the accuracy of neural connections both in the neurotransplants themselves and in the recipient’s brain. The degree of specificity of synaptic contacts during transplantation of the hippocampal formation into the rat neocortex was studied. Using the method of electron microscopy, it was shown that in the transplants themselves mainly specific forms of synapses were differentiated, which were topographically correctly located on the soma-dendritic surface of neurons. The axons of the transplanted neurons growing into the recipient’s brain formed synaptic contacts with normally unusual neurons. During the formation of nonspecific axonal connections, they modified the composition and distribution of neurotransmitter vesicles in presynaptic terminals, as well as inducing structural and chemical reorganization in postsynaptic dendrites.