RECENT IMMUNOCYTOCHEMICAL RESULTS OF LOCALIZATION OF VASOACTIVE-INTESTINAL-PEPTIDE IN HUMAN NASAL-MUCOSA

Besides classic neurotransmitters, neuropeptides seem to participate in the control of human nasal physiology. In this region vasoactive intestinal peptide (VIP) is found in higher concentrations than other neuropeptides. The aim of this study was to localize VIP in neuronal and non-neuronal structures of human nasal mucosa using immunocytochemical techniques. Paraffin and frozen serial sections of the inferior turbinate were incubated with antibodies against neuronspecific enolase (NSE) to demonstrate neuronal structures or against VIP. The immunecomplexes were visualized by the Avidin-Biotin-Complex (ABC)-method, VIP-positive nerve fibers were found around the acinus cells and the ducts of seromucous glands. These results emphasize the influence of VIP on nasal gland secretion. Few immunoreactions to the VIP antibody were demonstrated in nerves of the adventitia of veins and arteries. Additionally, by comparing NSE and VIP localization, strong extranerval immunoreactions in the tunica medica of arterioles were demonstrated, as were lesser but still visible immunoreactions in the muscular layer of thick veins. These morphological findings in vessels and the well known vasodilatory effect of VIP underline the functions of this neuropeptide on nasal mucosa in man. Thus, by increasing the blood flow and volume, VIP, in conjunction with other control factors, seems to participate in the physiological processes of the swelling mechanism of nasal turbinates and influence nasal congestion.