Distribution of Endothelin-1 like Activity in the Endolymphatic Sac of Normal Guinea Pigs

Abstract

Endothelin-1 (ET-1), originally characterized as a 21-residue vasoconstrictor peptide from endothelial cells, has been reported to act as a local hormonal regulator of pressure, fluid, ions as well as neuropeptides. The present study investigated the distribution of ET-1 in the endolymphatic sac and duct of normal guinea pigs, by immunohistochemistry. ET-I like activity was identified in the epithelial cells and subepithelial connective tissue of the endolymphatic sac and duct. No significant difference was seen in intensity of ET-1 like activity throughout the endolymphatic sac, but the epithelial cells lacked a uniform pattern in the intermediate and proximal portions. These findings suggest that ET-1 may play an important role in the regulation of inner ear pressure, fluid volume, and ion balance.

Key Words:

• endothelin-1
• endolymphatic sac
• guinea pig