CALCITONIN-GENE-RELATED PEPTIDE (CGRP)-LIKE IMMUNOREACTIVITY IN MOTONEURONS OF THE HUMAN SPINAL-CORD FOLLOWING INJURY

Changes that occur in the localization of calcitonin gene-related pept ide-like-immunoreactivity (CGRP-LI) in motoneurons, following injury t o the human spinal cord, were examined. CGRP-LI above and below the le vel of injury was compared to normal human spinal cord. Vibratome sect ions were cut and processed for immunostaining using the avidin-biotin immunoperoxidase method. Whereas motoneurons above the lesion contain ed CGRP-LI, below the lesion the CGRP-LI was reduced. In 3 spinal cord s from patients who had survived between 1 and 8 years after injury, C GRP-LI in motoneurons of lumbar spinal cord was absent or considerably diminished. In the spinal cord from one patient who had died several years after injury, there was a unilateral augmentation of CGRP immuno staining. The results suggest that CGRP levels in motoneurons are affe cted by spinal cord injury in humans and that CGRP levels in motoneuro ns may be regulated either by supraspinal afferent inputs or by muscle activity.