Effects of amiloride on the endolymphatic sac

The effect of amiloride on the murine endolymphatic sac was investigated. The amiloride caused collapse of the lateral intercellular spaces in the endolymphatic sac epithelium and a subsequent mild endolymphatic hydrops. These changes indicated a decreased absorption of endolymph in the endolymphatic sac. Amiloride is known to inhibit the transcellular fluid transport without inducing any changes in the paracellular fluid transport. It is therefore suggested that amiloride specially inhibits the fluid and ion exchange in the apical portion of the epithelial cells resulting a decrease in transcellular fluid transport across the endolymphatic sac epithelium. The transcellular fluid transport seems to be one of the main mechanisms in the endolymphatic sac fluid exchange system.