The effects of V2 antagonist (OPC-31260) on endolymphatic hydrops

Takeda, Taizo; Sawada, Shoichi; Takeda, Setsuko; Kitano, Hiroya; Suzuki, Mikio; Kakigi, Akinobu; Takeuchi, Shunji

doi:10.1016/s0378-5955(03)00135-7

Cited by 71 publications

(58 citation statements)

References 30 publications

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“…These results indicate that lithium inhibits the VP-AQP2 system in the inner ear as well as in the kidney. Since OPC-31260, an inhibitor of the VP-AQP system, acted as a dehydrating agent of the endolymphatic space in our previous study [22] , it is likely that lithium may cause a reduction in endolymphatic volume. Indeed, the present morphological study indicated that lithium intake produced a dose-dependent reduction in the endolymphatic volume of the hydropic ear.…”

Section: Discussionmentioning

confidence: 80%

“…All animals underwent electrocauterization of the endolymphatic sac in the left ear via an epidural occipital approach. Details of surgical procedures were described in a previous report [22] .…”

Section: Experiments 2: Morphological Studymentioning

confidence: 99%

“…For the quantitative assessment of changes in endolymphatic space, the following four parameters ( fi g. 1 ) were measured in the basal, second, third and apical turns in the same way as previously described [22] : (1) the length of the extended Reissner's membrane (L), (2) the original length of Reissner's membrane (L*), (3) the cross-sectional area of the scala media (S), enclosed by the distended Reissner's membrane, and (4) the cross-sectional area of the original scala media (S*), enclosed by a straight line segment. The measuring system included a video camera, a computer, and a digitizer (Video Micro Meter VM-30, Olympus Co., Tokyo).…”

Section: Measurement Proceduresmentioning

confidence: 99%

“…It is also likely that the down-regulation of AQP protein and mRNA expressions reduces experimentally induced endolymphatic hydrops, as observed in the application of a V2-antagonist (OPC-31260) [22] . In the present study, molecular-biological and histochemical studies were performed to investigate the infl uence of lithium on the expressions of AQP2 protein and mRNA in the inner ear.…”

mentioning

confidence: 99%

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Effects of Lithium on Endolymph Homeostasis and Experimentally Induced Endolymphatic Hydrops

Fukushima

Takeda²,

Kakigi³

et al. 2005

ORL

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There is evidence to suggest that water homeostasis in the inner ear is regulated via the vasopressin (VP)-aquaporin 2 (AQP2) system in the same fashion as in the kidney. The VP-AQP2 system in the kidney is well known to be inhibited by lithium, resulting in polyuria due to a decrease in reabsorption of water in the collecting duct of the kidney. Therefore, lithium is also likely to inhibit the VP-AQP2 system in the inner ear, and consequently exert some influence on inner ear fluid homeostasis. In this study, we investigated the effects of lithium on AQP2 expression in the rat inner ear, and on the cochlear fluid volume in hydropic ears of guinea pigs. A quantitative PCR study revealed that lithium reduced AQP2 mRNA expression in the cochlea and endolymphatic sac. Lithium application also decreased the immunoreactivity of AQP2 in the cochlea and endolymphatic sac. In a morphological study, lithium intake significantly reduced endolymphatic hydrops dose-dependently. These results indicate that lithium acts on the VP-AQP2 system in the inner ear, consequently producing a dehydratic effect on the endolymphatic compartment.

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Section: Discussionmentioning

confidence: 80%

Section: Experiments 2: Morphological Studymentioning

confidence: 99%

Section: Measurement Proceduresmentioning

confidence: 99%

mentioning

confidence: 99%

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Effects of Lithium on Endolymph Homeostasis and Experimentally Induced Endolymphatic Hydrops

Fukushima

Takeda²,

Kakigi³

et al. 2005

ORL

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show abstract

“…The effects of vasopressin on inner ear fluid homeostasis is mediated by the vasopressin 2 receptor which, via effects on cAMP/Protein kinase A, lead to translocation of aquaporin 2 to the plasma membrane [Sawada et al, 2002, Takeda et al, 2003. In this study we demonstrate using 9.4 T field strength MRI in combination with intraperitoneally administered Gd contrast agent the development of EH in two mouse strains, C57BL6 and CBA/J mice, induced by chronic administration of vasopressin and comparing the same ear before and after treatment.…”

Section: Discussionmentioning

confidence: 99%

Vasopressin induces endolymphatic hydrops in mouse inner ear, as evaluated with repeated 9.4 T MRI

et al. 2015

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Expression of aquaporins in inner ear disease

Dong

Kim

et al. 2019

The Laryngoscope

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The inner ear is responsible for hearing and balance and consists of a membranous labyrinth within a bony labyrinth. The balance structure is divided into the otolith organ that recognizes linear acceleration and the semicircular canal that is responsible for rotational movement. The cochlea is the hearing organ. The external and middle ear are covered with skin and mucosa, respectively, and the space is filled with air, whereas the inner ear is composed of endolymph and perilymph. The inner ear is a fluid-filled sensory organ composed of hair cells with cilia on the upper part of the cells that convert changes in sound energy and balance into electric energy through the hair cells to transmit signals to the auditory nerve through synapses. Aquaporins (AQPs) are a family of transmembrane proteins present in all species that can be roughly divided into three subfamilies according to structure and function: 1) classical AQP, 2) aquaglyceroporin, and 3) superaquaporin. Currently, the subfamily of mammalian species is known to include 13 AQP members (AQP0-AQP12). AQPs have a variety of functions depending on their structure and are related to inner ear diseases such as Meniere's disease, sensorineural hearing loss, and presbycusis. Additional studies on the relationship between the inner ear and AQPs may be helpful in the diagnosis and treatment of inner ear disease.

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The effects of V2 antagonist (OPC-31260) on endolymphatic hydrops

Cited by 71 publications

References 30 publications

Effects of Lithium on Endolymph Homeostasis and Experimentally Induced Endolymphatic Hydrops

Effects of Lithium on Endolymph Homeostasis and Experimentally Induced Endolymphatic Hydrops

Vasopressin induces endolymphatic hydrops in mouse inner ear, as evaluated with repeated 9.4 T MRI

Expression of aquaporins in inner ear disease

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