title: Calcium Metabolism Profile in Rat Inner Ear Indicated by MRI After Tympanic Medial Wall Administration of Manganese Chloride.
abstract: OBJECTIVE
  To evaluate the efficacy of the novel method for the targeted delivery of Mn(++) to the inner ear and monitor calcium metabolism activity in the inner ear.
  
  
  METHODS
  Dynamic signal changes of Mn(++) in the rat inner ear were followed using T1-weighted magnetic resonance imaging (MRI) after administration of 2.5 µl MnCl₂(500 mM) to the medial wall of the middle ear cavity.
  
  
  RESULTS
  Mn(++) passed through both the oval and round windows and distributed in the perilymphatic compartments, where it formed bright sharp lines along the fluid-cellular borders 12 minutes post administration and entered the endolymph sufficiently after 45 minutes. After 6 hours, the distribution of Mn(++) shifted from a fluid-dominant pattern to a cell-dominant pattern. Mn(++) concentrated in the area of the basilar membrane, periphery process, and soma of the spiral ganglion on day 2; became more distinguishable on day 4; declined on day 8; and remained detectable for 16 days post administration.
  
  
  CONCLUSIONS
  The novel targeted delivery method efficiently introduced Mn(++) into the inner ear. The dynamic distribution pattern of Mn(++) in the inner ear shown by MRI indicates that this method can be used to monitor calcium metabolism activity in the inner ear.
authors.affiliation: Hearing and Balance Research Unit, Field of Oto-laryngology, School of Medicine, University of Tampere, Tampere, Finland Department of Otolaryngology-Head and Neck Surgery, Center for Otolaryngology-Head & Neck Surgery of Chinese PLA, Changhai Hospital, Second Military Medical University, Shanghai, China Jing.Zou@uta.fi zoujinghb@hotmail.com.
authors.forename: Jing
authors.initials: J
authors.lastname: Zou
authors.affiliation: Hearing and Balance Research Unit, Field of Oto-laryngology, School of Medicine, University of Tampere, Tampere, Finland.
authors.forename: Ilmari
authors.initials: I
authors.lastname: Pyykkö
mesh_terms: D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002712:Chlorides / Q000008:administration & dosage* / Q000493:pharmacokinetics*; D007758:Ear, Inner / Q000378:metabolism*; D004432:Ear, Middle; D000069555:Injection, Intratympanic; D008279:Magnetic Resonance Imaging; D017895:Manganese Compounds / Q000008:administration & dosage* / Q000493:pharmacokinetics*; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D002712:Chlorides; D017895:Manganese Compounds; C025340:manganese chloride; D002118:Calcium
keywords: Ion channel; animal; biological barrier; imaging; inner ear; metabolism