The purpose of this study was to elucidate the influence of otitis media on blood flow in the lateral wall of the cochlea by means of a model of endotoxin-induced otitis media. The cochlear blood flow (CBF) following lipopolysaccharide inoculation into the middle ear cavities of rats was measured by laser-Doppler flowmetry and compared with that of untreated ears. After this evaluation, the influence on CBF of concomitant use of a nitric oxide synthase inhibitor was also investigated. The first day after inoculation, the CBF of treated ears decreased significantly. This decrease recovered gradually between the 7th and 14th days. With concomitant use of a nitric oxide synthase inhibitor, the decrease in CBF was prevented to some extent. The results showed a functional influence upon CBF by endotoxin-induced otitis media. The significance of prophylactic use of the drug is also discussed in regard to the effect on CBF following otitis media.
PaparellaMMMorizonoTLeCT. Sensorineural hearing loss in otitis media. Ann Otol Rhinol Laryngol1984; 93: 623–9.
2.
MorizonoTGiebinkGSPaparellaMMSikoraMASheaD. Sensorineural hearing loss in experimental purulent otitis media due to Streptococcus pneumoniae. Arch Otolaryngol1985; 111: 794–8.
3.
KawauchiHDeMariaTFLimDJ. Endotoxin permeability through the round window. Acta OtolaryngolSuppl (Stockh) 1989(suppl 457): 100–15.
4.
SpandowOAnnikoMHellströmS. Inner ear disturbances following inoculation of endotoxin into the middle ear. Acta Otolaryngol (Stockh)1989; 107: 90–6.
5.
EngelFBlatzRSchliebsRPalmerMBhakdiS. Bacterial cytolysin perturbs round window membrane permeability barrier in vivo: Possible cause of sensorineural hearing loss in acute otitis media. Infect Immun1998; 66: 343–6.
6.
WatanabeKNaitoNTanakaY. Morphological changes in the inner ear induced by bacterial endotoxin. Med Electron Microsc1995; 28: 80–7.
7.
SoneMRusslieHQCanafaxDMPaparellaMM. Expression of intercellular adhesion molecule-1 in rat inner ear due to bacterial otitis media. Ann Otol Rhinol Laryngol1999; 108: 648–52.
8.
IchimiyaISuzukiMHiranoTMogiG. The influence of pneumococcal otitis media on the cochlear lateral wall. Hear Res1999; 131: 128–34.
9.
HessABlochWHuverstuhlJ. Expression of inducible nitric oxide synthase (iNOS/NOS II) in the cochlea of guinea pigs after intratympanical endotoxin-treatment. Brain Res1999; 830: 113–22.
10.
WatanabeKHessAZumegerC. Changes of the compound action potential (CAP) and the expression of inducible nitric oxide synthase (iNOS/NOS II) in the cochlea under the inflammatory condition. Hear Res2000; 145: 149–55.
11.
TakumidaMAnnikoMPopaRZhangDM. Lipopolysaccharide-induced expression of inducible nitric oxide synthase in the guinea pig organ of Corti. Hear Res2000; 140: 91–8.
12.
BrechtelsbauerPBNuttallALMillerJM. Basal nitric oxide production in regulation of cochlear blood flow. Hear Res1994; 77: 38–42.
13.
WatanabeKHessABlochWMichelO. Inhibition of inducible nitric oxide synthase lowers the cochlear damage by lipopolysaccharide in guinea pigs. Free Radic Res2000; 32: 363–70.
14.
PopaRAnnikoMTakumidaM. Otoprotectant minimizes hearing defects caused by Pseudomonas aeruginosa exotoxin A. Acta Otolaryngol (Stockh)2000; 120: 350–8.
15.
OhlsénKADidierABaldwinDMillerJMNuttallALHultcrantzE. Cochlear blood flow in response to dilating agents. Hear Res1992; 58: 19–25.
16.
LundmanLSantiPAMorizonoTHaradaTJuhnSKBagger-SjöbäckD. Inner ear damage and passage through the round window membrane of Pseudomonas aeruginosa exotoxin A in a chinchilla model. Ann Otol Rhinol Laryngol1992; 101: 437–44.
17.
StenqvistMAnnikoMPetterssonA. Effect of Pseudomonas aeruginosa exotoxin A on inner ear function. Acta Otolaryngol (Stockh)1997; 117: 73–9.
18.
OkamotoHItoORomanRJHudetzAG. Role of inducible nitric oxide synthase and cyclooxygenase-2 in endotoxin-induced cerebral hyperemia. Stroke1998; 29: 1209–18.
19.
HeymanSNDarmonDGoldfarbM. Endotoxin-induced renal failure. I. A role for altered renal microcirculation. Exp Nephrol2000; 8: 266–74.
20.
FessendenJDSchachtJ. The nitric oxide/cyclic GMP pathway: A potential major regulator of cochlear physiology. Hear Res1998; 118: 168–76.
21.
MichelOHessABlochWStennertESuJAddicksK. Localization of the NO/cGMP-pathway in the cochlea of guinea pigs. Hear Res1999; 133: 1–9.
22.
NakashimaTNuttallALMillerJM. Effects of vasodilating agents on cochlear blood flow in mice. Hear Res1994; 80: 241–6.
23.
NakaMNanbuTKobayashiK. A potent inhibitor of inducible nitric oxide synthase, ONO-1714, a cyclic amidine derivative. Biochem Biophys Res Commun2000; 270: 663–7.
