NERVE-FIBERS IMMUNOREACTIVE FOR SUBSTANCE-P AND CALCITONIN-GENE-RELATED PEPTIDE IN THE CERVICAL SPINAL VENTRAL ROOTS OF THE MOUSE

We demonstrate the existence of nerve fibers possessing substance P (S P) and calcitonin gene-related peptide (CGRP) immunoreactivity in the mouse cervical ventral roots. The distribution of the SP and CGRP fibe rs was similar, but CGRP fibers were generally more numerous. Both typ es entered the ventral pia mater or formed hairpin loops, but they did not enter the spinal cord directly through these roots. SP and CGRP f ibers in the ventral roots were thin and had many varicosities. We sug gest that these SP and CGRP fibers are involved not only in a sensory mechanism, but also in other functions, via the release of SP and CGRP from varicosities in the ventral roots.