Transplantation of dissociated foetal serotonin neurons into the transected spinal cord of adult rats.

Twenty adult rats underwent a complete section of the spinal cord at the lower thoracic level. One week later, 15 of them received a cell suspension obtained from raphe nuclei of 14-day-old foetuses into the distal fragment of the spinal cord. They were sacrificed after survival periods of 10-60 days, and vibratome sections of the spinal cord were processed for immunocytochemical detection of serotonin (5-HT). The control, non-transplanted animals showed a total absence of 5-HT immunoreactivity below the section, whereas the transplanted rats showed many immunoreactive 5-HT perikarya in the graft region, some at a distance of up to 10 mm, and a progressive innervation of the whole grey matter extending at least over 20 mm from the graft site.