NEUROPEPTIDE PARTICIPATION IN CANINE LARYNGEAL SENSORY INNERVATION - IMMUNOHISTOCHEMISTRY AND RETROGRADE LABELING

We investigated the quantitative participation of calcitonin gene-rela ted peptide (CGRP), substance P (SP), and leu-enkephalin (ENK) in cani ne laryngeal sensory innervation by immunohistochemistry in combinatio n with retrograde labeling using the recently introduced retrograde tr acer cholera toxin subunit B-conjugated gold (CTBG). In the nodose gan glion, neurons labeled from the internal branch of the superior laryng eal nerve with CTBG were investigated immunohistochemically by means o f antisera against CORP, SP, and ENK. The percentages of neurons immun oreactive to each neuropeptide were as follows: CGRP 81.5%, SP 24.5%, and ENK 7.0%. These results suggest that CGRP is the main sensory neur otransmitter in canine laryngeal sensory innervation.