Differentiation of Cholinergic Neurons in Rat Spinal Cord under Conditions of Allotransplantation into a Peripheral Nerve and In Situ Development

The method of ectopic transplantation of embryonic anlages of CNS allows studying histoblastic potencies of progenitor cells developing under conditions of changed microenvironment. Some progenitor cells in the transplants of rat embryonic spinal cord retained their ability to express choline acetyltransferase after transplantation into the sciatic nerve of adult animals. Comparative analysis of cholinergic neurons in the neurotransplants and neurons formed in rat spinal cord during normal ontogeny showed that choline acetyltransferase-positive cells after transplantation into the nerve reached morphological differentiation of motor neurons at later terms than cells developing in situ. They were scattered one by one and did not form nuclear nerve centers. We did not find structures similar to presynaptic cholinergic buds typical of intact spinal cord near these cells throughout the observation period. Solitary cholinergic neurons survived in the transplants for 19 months.