AQP2 and Tinnitus: Increases in pAVP caused by stress and subsequent activation of the V2R-AQP2 intracellular signaling cascade and endosomal trapping of AQP2 in the endolymphatic sac might underlie the pathogenesis of the inner ear hydrops that results in the intermittent vertigo, hearing loss and tinnitus characteristic of Meniere's disease [9].