OCCURRENCE, DISTRIBUTION AND POSSIBLE ROLE OF THE REGULATORY PEPTIDE ENDOTHELIN IN THE NASAL-MUCOSA

Nasal blood flow is finely regulated by local release of neurotransmit ters, neuropeptides and other bioactive molecules acting via paracrine mechanisms. We have investigated the occurrence and distribution in h uman nasal mucosa of endothelin, a potent vasoconstrictor peptide, by immunocytochemistry and the effect of systemic administration of endot helin-1 on vascular perfusion of rabbit nasal mucosa by laser Doppler flowmetry. Endothelin-like immunoreactivity was demonstrated within va scular endothelial cells in both developing and mature human mucosa. N asal epithelial cells and some connective tissue cells, presumed to be macrophages, also displayed specific immunostaining. In rabbits injec ted with endothelin-1, a potent and prolonged nasal vasoconstriction w as observed. It is suggested that endothelin released locally may part icipate in the regulation of nasal blood flow via paracrine mechanisms . Since endothelin has growth-promoting actions on several cell types, it is also tentatively proposed that this regulatory peptide may play a role during development of the nose.