Plasma Vasopressin and V2 Receptor in the Endolymphatic Sac in Patients With Delayed Endolymphatic Hydrops

Abstract

Civilized people are frequently exposed to stress in their daily life, and pAVP can easily become elevated at any time. Therefore, a negative feedback system between pAVP and V2R in the endolymphatic sac may function for inner ear fluid homeostasis against stress-induced increases in pAVP. For the pathogenesis of endolymphatic hydrops resulting in vertigo attacks in patients with DEH as well as MD, pAVP may represent a matter of consequence, but V2R overexpression in the endolymphatic sac could be much more essential as a basis for these diseases.

Endolymphatic Hydrops: Pathophysiology and Experimental Models

“…One study has suggested that the endolymphatic sacs of patients with Meniere's disease have significantly higher vasopressin receptor levels, suggesting that the ears of these patients may be more sensitive to vasopressin (60). Other studies have reported elevated systemic vasopressin levels in Meniere's patients (61, 62, 63). One recent study showed that increasing the water intake of Meniere's patients, presumed to reduce the systemic vasopressin level, reduced the severity of their symptoms (64).…”

Endolymphatic sac tumor with overexpression of V2 receptor mRNA and inner ear hydrops

“…These findings suggest that MD-like symptoms could be due to inner ear hydrops [13,14] induced by ELSTs. Furthermore, the molecular biological examination also revealed that V2R mRNA expression in the endolymphatic sac of both cases of ELST was up-regulated, as seen in MD, compared with controls of VS [5,7]. Based on our recent molecular biological studies in the endolymphatic sac of MD [5,6] and delayed endolymphatic hydrops [7], there was a strong relationship between the pathogenesis of inner ear hydrops and the intracellular signal cascade of V2R in the endolymphatic sac.…”

“…Furthermore, the molecular biological examination also revealed that V2R mRNA expression in the endolymphatic sac of both cases of ELST was up-regulated, as seen in MD, compared with controls of VS [5,7]. Based on our recent molecular biological studies in the endolymphatic sac of MD [5,6] and delayed endolymphatic hydrops [7], there was a strong relationship between the pathogenesis of inner ear hydrops and the intracellular signal cascade of V2R in the endolymphatic sac. All these findings suggest that the inflammation in the endolymphatic sac in case 1 and the tumor pressure in the endolymphatic sac of case 2 might have an effect on the endolymphatic environment, probably through the overexpression of V2R mRNA in the endolymphatic sac.…”

“…Based on our recent molecular biological studies of the endolymphatic sac in MD [5,6] and delayed endolymphatic hydrops [7], strong relationships were revealed between the pathogenesis of inner ear hydrops and the intracellular signal cascade of antidiuretic stress hormone vasopressin type-2 receptor (V2R) in the endolymphatic sac. Therefore, in the present ELST study, we focused on V2R expression in the endolymphatic sac.…”

Ion homeostasis in the ear: mechanisms, maladies, and management

“…It has been challenging to develop the causative relationship between elevated serum vasopressin and Meniere's disease since the symptoms are usually unilateral. Recently it was determined that mRNA of the vasopressin receptor is expressed at much higher levels in the endolymphatic sac of Meniere's patients [86–87]. This lead to the conclusion that it is the unilateral cochlear elevation of receptor expression, coupled with slightly higher serum levels, that causes unilateral Meniere's.…”