title: Cochlear blood flow during occlusion and reperfusion of the anterior inferior cerebellar artery--effect of topical application of dexamethasone to the round window.
abstract: CONCLUSIONS
  Topical application of dexamethasone may support autoregulation of cochlear blood flow (CBF), although it had no direct effect on CBF.
  
  
  OBJECTIVE
  Although intratympanic steroid therapy for patients with inner ear disorders is common, the mechanism by which steroids exert their effect is unclear. We investigated the response of CBF to topical application of dexamethasone onto the round window.
  
  
  METHODS
  Two concentrations of dexamethasone (3.3 mg/ml and 33 mg/ml dexamethasone in 0.5 microl saline) were applied to the round windows of rats, and CBF responses were measured using a laser Doppler flowmeter. The effects on CBF of a 2 h occlusion of the anterior inferior cerebellar artery (AICA) and subsequent release of the clamp with or without previous dexamethasone application were investigated.
  
  
  RESULTS
  No significant change in CBF was observed after topical application of dexamethasone, and it did not affect the decrease in CBF caused by AICA occlusion. However, recovery of CBF after release of the AICA clamp was better in animals treated with dexamethasone than in those that did not receive dexamethasone.
authors.affiliation: Department of Otorhinolaryngology, Nagoya University School of Medicine, Nagoya, Japan.
authors.forename: Hironao
authors.initials: H
authors.lastname: Otake
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Yamamoto
authors.forename: Masaaki
authors.initials: M
authors.lastname: Teranishi
authors.forename: Michihiko
authors.initials: M
authors.lastname: Sone
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Nakashima
mesh_terms: D000287:Administration, Topical; D000818:Animals; D000893:Anti-Inflammatory Agents / Q000494:pharmacology*; D002531:Cerebellum / Q000098:blood supply*; D003051:Cochlea / Q000098:blood supply*; D003907:Dexamethasone / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D005260:Female; D006706:Homeostasis / Q000187:drug effects; D007511:Ischemia / Q000503:physiopathology; D051381:Rats; D017207:Rats, Sprague-Dawley; D012039:Regional Blood Flow / Q000187:drug effects / Q000502:physiology; D015427:Reperfusion Injury / Q000503:physiopathology*; D012405:Round Window, Ear / Q000187:drug effects / Q000503:physiopathology
chemical_list: D000893:Anti-Inflammatory Agents; D003907:Dexamethasone