Vol.101 No.5 contentsPRACTICA OTO-RHINO-LARYNGOLOGICA
Vol. 101 No. 5 May 2008
The Inner Ear and Water Metabolism
Tadashi Kitahara and Takeshi Kubo
(Osaka University Graduate School of Medicine)
Some diseases are well known to be provoked by inadequate adaptation to physical and/or psychogenic stress in daily life. Attacks of Meniere's disease characterized by vertigo, fluctuating hearing loss and tinnitus due to inner ear pathology represent a common example. Furthermore, this disease has been proposed to be more prevalent among technologically advanced societies where people live a stressful lifestyle, i.e. "Menierization is civilization". However, it is very difficult to prove a significant relationship between stress and inner ear pathology, since the definition of stress is too obscure for scientific analysis of these aspects.
Since the oto-pathology in Meniere's disease was first identified as being inner ear endolymphatic hydrops through temporal bone studies in 1938, it has gradually become understood that inner ear endo-organ tissues, including the endolymphatic sac, prepare the fluid homeostatic system via water metabolism-related molecules such as vasopressin and aquaporin. Subsequently, it was proposed that the pathogenesis in Meniere's disease could be inner ear endolymphatic hydrops due to a disorder of water metabolism-related molecules.
In the present paper, we would like to discuss the neuroscientific relationship between stress and inner ear pathology by reviewing plasma vasopressin (an anti-diuretic stress hormone) and its receptor, V2 receptor, in the endolymphatic sac (an inner ear endo-organ for endolymph absorption) in patients with Meniere's disease.
Key words :stress, Meniere's disease, vasopressin, V2 receptor, endolymphatic sac.