[Transplantation of fetal neurons into the spinal cord after section]

The transection of spinal cord can be seen as an interruption of the continuity in between the control command and the peripheral reception. The consequence is an anarchic reorganization of the distal spinal cord often responsible of spasticity and painful rigidity. We have, in a first step, sectioned the spinal cord at lower thoracic level in adult rats. Knowing the modulatory role of aminergic neurotransmitters, we have then one week later transplanted foetal 5-HT neurons into the distal segment of the cord, in half of the transsected animals. Functional results suggest the constitution of sphincteral autonomy in the grafted animals whereas the controls showed either an acute urine retention leading to death within two to three weeks after the section, or an absence of sphincteral control. Immunocytochemical study with specific 5-HT antibodies showed adult-looking neurons extending processes towards the intermediolateral nucleus and the anterior horn. Ultrastructural immunocytochemistry disclosed afferent and efferent synapses to the grafted neurons.