Serotonin controls axon and neuronal regeneration in the nervous system: lessons from regenerating animal models

摘要

Traumatic brain injury (TBI) is a mechanical injury to brain tissue that leads to an impairment of function and a broad spectrum of symptoms and disabilities; often, it is followed by diffuse axonal injury, which causes denaturation of the white matter and axon retraction, leaving patients with severe brain damage or even in a persistent vegetative state. Spinal cord injury (SCI) is defined as a lesion within the spinal cord that results in the disruption of nerve fibre bundles that convey ascending sensory and descending motor information. In mammals, including humans, SCI can lead to per-manent disability and an irreversible loss of function below the site of injury due to the disruption of motor, sensory and autonomic systems. The inability of axons to regrow within the injured central nervous system (CNS) of adult mammals is a fundamental feature that explains the poor regenerative capacity observed after TBI or SCI. In addition, TBI and SCI cause a loss of cells (neurons and glia) due to the primary physical injury. Also, after the primary injury, a cascade of secondary injury events expands the zona of neural tissue injury causing further cell death.