Co-localization of vasoactive intestinal peptide- and substance P-containing nerves in cat bronchi.
The occurrence of vasoactive intestinal peptide (VIP) and substance P in nerve fibers within the lung is well established, and both VIP- and substance P-containing nerve fibers are known to supply pulmonary vascular and bronchial smooth muscle and submucosal glands. In the present study, we have investigated the co-localization of these two peptides in cat lung. The co-localization procedure follows a standard immunocytochemical protocol except that the primary and labeled secondary antisera each contain a combination of two antisera allowing the simultaneous detection of two antigens in a single tissue section. Using fluorescence microscopy, VIP- and substance P-containing nerve fibers were co-localized in bronchial smooth muscle, in the walls of pulmonary and bronchial arteries, and around submucosal glands. VIP and substance P were also co-localized in nerve cell bodies that comprised the intrinsic airway ganglia. Substance P-containing nerve fibers were observed within the bronchial epithelium, but VIP was not present at this location. The co-localization of VIP and substance P in the same nerve fibers suggests that airway and pulmonary vascular function may be partially regulated by the simultaneous or sequential release of VIP and substance P from the same nerve fibers. The results also suggest that, in addition to extrinsic nerve fibers that contain substance P, the airways of cats are supplied by substance P-containing nerve fibers that originate from intrinsic nerve cell bodies.
D000818:Animals; D001980:Bronchi / Q000032:analysis / Q000098:blood supply / Q000294:innervation*; D002415:Cats; D009412:Nerve Fibers / Q000032:analysis*; D013373:Substance P / Q000032:analysis*; D014660:Vasoactive Intestinal Peptide / Q000032:analysis*
D013373:Substance P; D014660:Vasoactive Intestinal Peptide