Similar distribution of mast cells and substance P- and calcitonin gene-related peptide-immunoreactive nerve fibers in the adult human larynx.

The mechanisms causing supraglottic and subglottic edema in the human larynx are not fully understood. Substance P (SP)- and calcitonin gene-related peptide (CGRP)-containing nerve fibers and mast cells have been suggested to induce inflammation and edema in other parts of the body. In this study of the adult human larynx the distribution of mast cells was studied in relation to SP- and CGRP-containing nerve fibers. Substance P- and CGRP-immunoreactive nerve fibers and numerous mast cells were found in the epiglottis and in the subglottic region of the larynx. Only occasional mast cells and no nerve fibers showing SP- or CGRP-like immunoreactivity were found in the vocal cords. In conclusion, the present study has shown that the distribution of nerve fibers showing SP- and CGRP-like immunoreactivity and mast cells has a similar regional variability. As the highest density of SP- and CGRP-containing nerve fibers and mast cells was present in the regions of the larynx where edema occurs, SP, CGRP, and/or mast cells might be involved in the pathogenesis of edema.