2013 Fiscal Year Final Research Report

Study of the function of the endolymphatic sac on the regulation of endolymphatic pressure

Research Project

Project/Area Number	23791902
Research Category	Grant-in-Aid for Young Scientists (B)
Allocation Type	Multi-year Fund
Research Field	Otorhinolaryngology
Research Institution	Kagawa University
Principal Investigator	INAMOTO RYUHEI 香川大学, 医学部附属病院, 助教 (50581047)
Project Period (FY)	2011 – 2013
Keywords	内リンパ静水圧 / 蝸牛 / 前庭 / カテコールアミン / 内リンパ嚢
Research Abstract	The endolymphatic sac (ES) is part of the inner ear and is believed to absorb endolymph. Obliteration of the ES and the endolymphatic duct cause accumulation of endolymph in the cochlea, the vestibule and the semicircular canals. This condition referred to as endolymphatic hydrops.Endolympatic hydrops in the cochlea causes deafness, while endolymphatic hydrops in the vestibule causes vertigo. Therefore, endolymph regulation is essential for normal hearing and the sense of equilibrium. The present study demonstrated that the hydrostatic pressure of ampullar endolymph is similar in magnitude to that of cochler endolymph, and that isoproterenol elevated the hydrostatic pressure of ampullar endolymph likely via its action on the ES to a significant smaller degree than that of cochlear endolmph. The results imply that catecholamines would regulate the hydrostatic pressure of the endolymphatic system in a different manner.