Presence of vasoactive intestinal peptide receptors in nasal mucosa

In recent years several tachykinins have been identified in the airway sensory nerves. Since the physiological and pathophysiological effects of neuropeptides depend on their functionally relevant concentrations and presence of specific receptors in the target tissue, specimens of enlarged turbinates and nasal polyps were removed in 11 patients and examined for the presence of vasoactive intestinal peptide (VIP) receptors. An intensive color reaction was observed in the cytoplasm of the tubular mucosa cells in polyps and turbinates as well as in the epithelium and submucosal glands. Since both these tissues reacted with VIP receptor antibody, noncross-reacting antibody against dendritic reticular cells (DRC 6-B7), nonspecific binding is possible, however it also must be speculated that the unspecific binding is overlaying specific binding. In addition a large number of cells located diffusely or in close association in the subepithelium and interstitial tissue stained only with VIP-specific antibody, indicating specific receptor binding. The color reaction is limited to the cell membrane and the cytoplasm of these cells was clearly eosinophilic. These cells were located in close proximity of the blood vessels, very indicative for active migration. Since VIP-positive nerves are also located near the blood vessels an activation process of these cells with subsequent release of enzymes and other active proteins is possible, thus influencing the inflammatory response.