Effect of inner ear blood flow changes in Ménière's model mice.
CONCLUSIONS
The endolymphatic sac (ES) is important for inner ear fluid homeostasis. A dysfunctional ES can cause vertigo attacks following additional stress such as a sudden change in endolymphatic volume and/or pressure, or restricted inner ear blood flow.


OBJECTIVE
The purpose of this study was to elucidate the mechanism of vertigo attacks in Ménière's disease.


METHODS
Adult CBA/J mice were given an intratympanic injection of lipopolysaccharide and an intraperitoneal injection of aldosterone. These 'model' animals had epinephrine or sodium nitroprusside (SNP) instilled into the middle ear cavity. Cochleae, vestibules, and endolymphatic sacs were studied morphologically by light microscopy.


RESULTS
The injection of epinephrine into the model animals reduced the endolymphatic hydrops in the cochlea, but also produced mild hydrops in the vestibule, which was never observed in untreated (control) animals. The ES did not react to epinephrine in the normal way. Injection of SNP did not cause any changes.
Takumida
Masaya
M
Department of Otolaryngology, Hiroshima University Faculty of Medicine, 1-2-3 Kasumicho, Minamiku, Hiroshima, Japan. masati@hiroshima-u.ac.jp
Akagi
Nana
N
Anniko
Matti
M
D000818:Animals; D004195:Disease Models, Animal; D007758:Ear, Inner / Q000098:blood supply / Q000187:drug effects* / Q000473:pathology*; D004837:Epinephrine / Q000494:pharmacology; D007267:Injections; D008575:Meniere Disease / Q000139:chemically induced / Q000473:pathology*; D051379:Mice; D008808:Mice, Inbred CBA; D008853:Microscopy; D009599:Nitroprusside / Q000494:pharmacology; D014662:Vasoconstrictor Agents / Q000494:pharmacology; D014665:Vasodilator Agents / Q000494:pharmacology
D014662:Vasoconstrictor Agents; D014665:Vasodilator Agents; D009599:Nitroprusside; D004837:Epinephrine