PEPTIDE-CONTAINING NERVE-FIBERS IN HUMAN AIRWAYS - DISTRIBUTION AND COEXISTENCE PATTERN

The occurrence, distribution and coexistence pattern of an array of ne uropeptides and tyrosine hydroxylase in the human larynx, trachea, bro nchi and lungs were studied by immunocytochemistry. A rich supply of n erve fibers containing vasoactive intestinal peptide (VIP) was seen cl ose to blood vessels, glands and nonvascular smooth muscle. Pituitary adenylate cyclase-activating peptide (PACAP)-containing fibers were nu merous among bundles of smooth muscle. Moderate numbers of helospectin -containing nerve fibers were seen in the nonvascular smooth muscle. T he majority of neuropeptide Y (NPY)-containing fibers were located in the nonvascular smooth muscle; some fibers also occurred around blood vessels and glands. Substance P (SP) and calcitonin gene-related pepti de (CGRP) -containing fibers were generally few and distributed beneat h the epithelium, among bundles of smooth muscle, around blood vessels and glands. A conspicuous finding was the lack of SP- and CGRP-contai ning fibers within the respiratory epithelium. Galanin-containing nerv e fibers were moderate in number among bundles of smooth muscle. Tyros ine hydroxylase-containing fibers were numerous around blood vessels a nd glands. The majority of the VIP-containing nerve fibers present in nonvascular smooth muscle also stored PACAP and helospectin. A subpopu lation of VIP-containing fibers in both vascular and nonvascular smoot h muscle and around glands stored NPY. Additionally, galanin was found to occur in many VIP-containing fibers located among bundles of smoot h muscle.