Effect of inner ear blood flow changes on the endolymphatic sac

Abstract

Conclusions: That the endolymphatic sac (ES) reacts to changes in inner ear blood flow may be important for homeostasis of the inner ear fluid volume and pressure.

Objectives: To elucidate the effect of changes in inner ear blood flow on the ES and to learn more about the volume and pressure regulatory function of the ES.

Materials and methods: Epinephrine or sodium nitroprusside (SNP) was injected into the middle ear cavity of adult CBA/J mice. The ES were analyzed morphologically by light microscopy.

Results: Epinephrine reduced the luminal size of the ES leading to an accumulation of intraluminal homogeneous substance. Injection of SNP increased the size of the ES lumen, accompanied by a collapse of the lateral intercellular space (LIS) and dense perisaccular tissue. These changes were almost reversed 4 h after injection.