Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P01185 (vasopressin)
 23,126 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Meniere's disease is peculiar to humans and is characterised by episodic vertigo, fluctuating hearing loss and tinnitus, and attacks of the affliction occurring under conditions of stress. Its pathology was first revealed to be inner ear hydrops through temporal bone studies in 1938. Although subsequently proposed as a disorder of water metabolism in the inner ear, its pathogenesis remains unsolved. The present study aimed to assess the link between the inner ear pathology in Meniere's disease and vasopressin, an anti-diuretic stress hormone with a potential role in inner ear fluid homeostasis. Blood samples were obtained from Meniere's disease patients in the morning, before any surgical treatment, to examine plasma vasopressin (pAVP) levels, and then from inner ear tissue during surgical treatment, to examine vasopressin type-2 receptor (V2R) in the endolymphatic sac. pAVP and the relative V2R mRNA expression in the endolymphatic sac were examined using a real-time polymerase chain reaction. Relative cAMP activity in the endolymphatic sac was also examined using tissue culture and cAMP assay. Both pAVP (1.6-fold versus controls; P = 0.048) and inner ear V2R mRNA expression (41.5-fold versus controls; P = 0.022) were significantly higher in Meniere's patients. cAMP activity was basally up-regulated (2.1-fold versus controls) and cAMP sensitivity to vasopressin application was largely elevated (4.9-fold versus controls) in Meniere's patients. We conclude that, in the pathogenesis of inner ear hydrops, resulting in Meniere's attacks, elevation of pAVP levels (probably as a result of stress) may present as a matter of consequence, but susceptibility of the V2R-overexpressed and cAMP-hypersensitized inner ear to pAVP elevation might be essential as the basis of this disease. Further experimental and clinical studies are needed to better clarify the relationship between Meniere's disease and stress.
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PMID:Meniere's attacks occur in the inner ear with excessive vasopressin type-2 receptors. 1909 77

Meniere's disease, characterised by episodic vertigo, fluctuating hearing loss and tinnitus, can occur under conditions of stress. Its pathology was first revealed to be inner ear hydrops through temporal bone studies in 1938. Although its pathogenesis has been proposed to be a disorder of water transport in the inner ear, subsequently, it remains unsolved, until now. A recent study revealed that both plasma stress hormone, vasopressin (pAVP) and its receptor, V2 (V2R) expression in the inner ear endolymphatic sac were significantly higher in Meniere's patients. In the present study, to link V2R-related molecules and inner ear hydrops, we examined V2R-linked water channel molecule, aquaporin-2 (AQP2) expression and translocation in human endolymphatic sac. AQP2 mRNA expression in the endolymphatic sac was significantly higher in Meniere's patients by using real-time polymerase chain reaction, as further confirmed by western blotting. AQP2-like immunoreactivity (-LIR) was translocated from luminal to basolateral side with endosomal trapping in the endolymphatic sac at the time of AVP exposure in human endolymphatic sac tissue culture. The similar AQP2-LIR translocation was also demonstrated by forskolin and blocked by vasopressin/V2R specific antagonist, OPC31260 and protein kinase A (PKA) specific antagonists, H-89 and KT-5720. We concluded that in the pathogenesis of inner ear hydrops resulting in Meniere's attacks, pAVP elevation as a result of stress and subsequent V2R-cAMP-PKA-AQP2 activation and endosomal trapping of AQP2 in the endolymphatic sac, might be important as a basis of this disease. Further experimental and clinical studies are needed to better clarify the neuroscientific relationship between stress and Meniere's disease.
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PMID:Expression and translocation of aquaporin-2 in the endolymphatic sac in patients with Meniere's disease. 2072 76

Despite the lack of clear evidence for their effectiveness in treating vertigo, tinnitus, hearing loss and aural fullness, diuretics, represent a common treatment for Meniere disease (MD), as they are supposed to decrease volume and pressure in the endolymphatic partition of the labyrinth. Our group have outlined the possibility of an adverse effect on inner ear function derived from an abrupt lowering of blood pressure: a subsequent exaggerated vasomotor response inducing local ischemia could be responsible for more or less permanent damage. The inner ear, owing both to its terminal vascular supply and to the necessity of a steady metabolism, seems a reliable target for any hemodynamic imbalance that acutely affect its perfusion. In our opinion, the complexity of the inner ear anatomy and function argues against the usefulness of diuretics to reduce endolymphatic volume, in analogy to their effect on the volemia: too many active mechanisms and "buffer" systems are involved in the labyrinth. Even considering that the finding of mean low pressure values is relatively common in subjects with MD, an attempt should be to maintain a stable blood perfusion to the labyrinth; in fact, an abrupt decrease in systemic blood pressure can trigger an adverse sympathetic reaction and transmit misleading information to the cochlear vasopressin receptors.
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PMID:Diuretics in Meniere disease: a therapy or a potential cause of harm? 2186 86