[NPY in human nasal mucosa -- an immunocytochemical and immunoelectron microscopical study]

The functions of the nasal mucosa are regulated by numerous endogenous and exogenous influences. The innervation patterns are important for the control of the physiological nasal functions. In addition to the classic neurotransmitters different neuropeptides might play a regulating and modulating role in the nasal mucosa. Both the significance and the localization of neuropeptide Y (NPY) have not been fully elucidated.

Tissue samples of human inferior turbinates from 42 patients were taken during nasal surgery and preserved in phosphate-buffered paraformaldehyde or glutaraldehyde. Serial sections were incubated with antibodies against NPY and the ABC method was applied. In order to identify immunoelectron microscopic reactions a streptavidin-gold-marker was used. The findings were photodocumented by using a light- and transmission-electron microscope.

NPY-positive terminals were mainly located in the adventitia of arterial vessels. There were also NPY-immunoreactive arterioles near to the glands. Periglandular a lower density of immunoreactions could be observed. NPY-positive fibers could be detected in the subepithelial connective tissue and at the glandular ducts. Immunoelectron microscopy revealed NPY within periglandular axons.

Immunohistochemical and immunoelectron microscopical methods allow a detailed identification of the sympathetic cotransmitter NPY in arterial vessels of nasal mucosa in man. These results indicate that NPY-containing nerve fibers innervate arteries as well as nasal glands. These findings suggest that NPY play a significant role as a neuromodulator in the control of both vasculature and glandular secretion. The localisation of NPY in periglandular and periductal nerves confirms the direct influence of glandular functions. NPY-agonists may be a beneficial additional treatment of rhinopathies to reduce nasal obstruction and mucus secretion.