RATIONALE: The symptoms of allergic rhinitis are considered to be a result of accumulation and activation of inflammatory cells. Furthermore, some neuropeptides like Calcitonin Gene Related Peptide (CGRP) and Substance P (SP) play an additional role in pathophysiology of allergic rhinitis.METHODS: Tissue samples from 38 human turbinates of patients with perennial rhinitis were taken during nasal surgery and preserved in phosphate-buffered glutaraldehyde. Ultrathin sections were cut and electron microscopy was performed. Additionally, samples were dehydrated and embedded in Araldit. Primary antibodies against CGRP and Substance P were applied and an immunocytochemical staining technique using a gold labeled antibody was carried out. Immunostained structures were photodocumented by using a transmission electron microscope.RESULTS: In the nasal mucosa an extensive edema and inflammatory cells like lymphocytes, plasma cells, eosinophiles and macrophages was found. The capillaries showed an activated endothelium. Immunoreactive nerve fibers were detected perivascular and in the periglandular tissue around the acini and ducts. Neuroglandular synapses with dense core vesicles and positive immunoreactions to CGRP and SP could be observed.CONCLUSIONS: Using electron microscopical techniques nerval structures near the submucosal glands could be demonstrated. Immunoreactions to the vasoactive neuropeptides CGRP and SP were detected in periglandular and perivascular nerves. These findings demonstrate the direct nerval influence on nasal mucosa in allergic rhinitis. CGRP and SP may induce vascular permeability and glandular secretion. These findings further elucidate pathomorphological mechanisms in allergic rhinitis. RATIONALE: The symptoms of allergic rhinitis are considered to be a result of accumulation and activation of inflammatory cells. Furthermore, some neuropeptides like Calcitonin Gene Related Peptide (CGRP) and Substance P (SP) play an additional role in pathophysiology of allergic rhinitis. METHODS: Tissue samples from 38 human turbinates of patients with perennial rhinitis were taken during nasal surgery and preserved in phosphate-buffered glutaraldehyde. Ultrathin sections were cut and electron microscopy was performed. Additionally, samples were dehydrated and embedded in Araldit. Primary antibodies against CGRP and Substance P were applied and an immunocytochemical staining technique using a gold labeled antibody was carried out. Immunostained structures were photodocumented by using a transmission electron microscope. RESULTS: In the nasal mucosa an extensive edema and inflammatory cells like lymphocytes, plasma cells, eosinophiles and macrophages was found. The capillaries showed an activated endothelium. Immunoreactive nerve fibers were detected perivascular and in the periglandular tissue around the acini and ducts. Neuroglandular synapses with dense core vesicles and positive immunoreactions to CGRP and SP could be observed. CONCLUSIONS: Using electron microscopical techniques nerval structures near the submucosal glands could be demonstrated. Immunoreactions to the vasoactive neuropeptides CGRP and SP were detected in periglandular and perivascular nerves. These findings demonstrate the direct nerval influence on nasal mucosa in allergic rhinitis. CGRP and SP may induce vascular permeability and glandular secretion. These findings further elucidate pathomorphological mechanisms in allergic rhinitis.