DISTRIBUTION OF NEUROPEPTIDES IN THE INFERIOR NASAL TURBINATE MUCOSA OF PATIENTS WITH ALLERGIC RHINITIS KAZUHIRO YAMAMOTO. M.D. Department of Otolaryngology, School of Medicine, Kitasato University, Sagamihara An immunohistochemical study was made on the distribution of neuropeptides in 36 surgical specimens of the inferior nasal turbinate mucosa obtained from 32 patients with allergic rhinitis. Eleven patients (15 specimens) of the 32 underwent chemosurgery in which trichloracetic acid (TCA) was used before excision. In these patients a watery nasal discharge remained even after TCA application, although the nasal obstruction decreased. As a control, 6 specimens obtained from 6 patients with non-allergic rhinitis were also studied. In the present study, the distribution of Substance P (SP) was examined as an index of the sensory nerve, whereas that of Vasoactive Intestinal Polypeptide (VIP) was examined as an index of the parasympathetic nervous system. The distribution of nerve fibers showing a positive reaction specific to each of the two types of neuropeptides was examined in the frontal sections of the specimens at distances of 5 and 15mm from the anterior tip of the inferior turbinate. In particular, the modes of the distribution in the superficial and deep layers of the mucosa were compared. It was found that, in the patients with allergic rhinitis who had not undergone TCA treatment, both SP-positive and VIP positive fibers were abundant in the anterior portion of the turbinate immediately beneath the basement membrane. In those patients who underwent chemosurgery prior to excision, SP-positive fibers were very scarce in both superficial and deep layers, whereas VIP-positive fibers appeared to exist only in the deep layer around the remaining nasal glands. In the specimens obtained from patients with non-allergic rhinits, there was no appreciable difference in the pattern of distribution of SP-and VIP -positive fibers among different sites of the specimens. The present study would indicate that chemosurgery using TCA inhibited the appearance of neuropeptides and resulted in improvement in clinical symptoms. However, in those patients having a continuous watery discharge even after TCA treatment, the function of the remaining nasal glands might be responsible for the symptom, although the contribution of VIP to the increase in vasopermeability should also be taken into consideration. Further studies are needed to determine the distribution of neuropeptides around the vessel walls. Key words: vasoactive intestinal polypeptide (VIP)

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