Chapter 24 Spinal cord motoneuron maintenance, injury and repair

Abstract

The motoneuron is dependent on interactions with its environment for its well-being and survival. In the studies discussed in the chapter, special attention has been given to the relationship with the myelinating cells in the peripheral nervous system (PNS), i.e., the Schwann cells, and the target muscle fibers in the skeletal muscles. By the search for molecules in Schwann cell types, a number of putative substances of relevance for motoneuron survival and regeneration have been identified. This chapter deals with the effect of such molecules in these test systems in mammals and considers cases of traumatic lesions to motoneurons, where it seems possible to find beneficial effects by providing lesioned cells with neurotrophic factors or substances counteracting molecules with a negative influence on the survival of neurons. Additionally, the chapter presents a technique to repair intraspinal and intramedullary motoneuron lesion. In patients that had sustained several spinal root avulsions, spinal cord implantation of the avulsed roots or nerve grafts were performed. Most patients having spinal cord implantation, showed signs of recovery. Electrophysiology indicated regeneration through the reimplanted roots or nerve grafts by means of muscle reinnervation potentials about 9 to 15 months after surgery.