CGRP-IMMUNOREACTIVE NERVE-FIBERS PROJECTING TO LUMBAR FACET JOINTS THROUGH THE PARAVERTEBRAL SYMPATHETIC TRUNK IN RATS

We previously reported that the L5-6 facet joint is innervated from DR Gs from L1 to L5 and the paravertebral sympathetic ganglia from T12 to L6 in rats. In the present study, to determine the sensory pathway fr om the L5-6 facet joint, we placed the fluorescent carbocyanine dye, D iI, in the L5-6 facet joint, and examined the paravertebral sympatheti c trunks and ganglia bilaterally. We found some DiI-labeled nerve fibe rs exhibiting calcitonin gene-related peptide (CGRP)-immunoreactivity, and some DiI-labeled neurons surrounded by CGRP-immunoreactive varico se fibers in the ganglia. The results suggest that a sensory pathway f rom the L5-6 facet joint to L1 and/or L2 DRGs is present in the parave rtebral sympathetic trunk, and that sensory nerve fibers may connect w ith sympathetic postganglionic neurons projecting to lumbar facet join ts. (C) 1996 Elsevier Science Ireland Ltd.