Endolymphatic Hydrops in Guinea Pigs After Cauterizing the Sac With Silver Nitrate

Studies of Cochlear Blood Flow in Guinea Pigs with Endolymphatic Hydrops

“…We observed the reduced magnitude of the CoBF changes in hydropic ears during infusion of various drugs. These results suggest that the cochlear microvascular sensitivity to various infusions is reduced in hydropic ears, and this may result from atrophy of the stria vascularis which is quite often observed in hydropic ears [7,8]. In the present study, atrophied stria vascularis was also observed in 55% of the hydropic cochlea ( fig.…”

“…This condition may be present concurrently with the impaired autoregulation in the cochlea as proposed by Yamamoto et al [11]. Since histopathological studies of human temporal bones with Ménière's disease and experimental hydrops in guinea pigs have often revealed atrophy of the stria vascularis [1][2][3][4][5][6][7][8], it is likely that atrophy of the stria vascularis may cause impaired autoregulation of the cochlea, resulting in the reduced magnitude of CoBF changes in the hydropic ears. This may also induce the slowly progressive deterioration of the inner ear condition with time.…”

“…In 20 of them, experimental endolymphatic hydrops was induced by silver nitrate cauterization [8] of the right endolymphatic sac (ES) 6-8 weeks prior to CoBF measurements. In brief, the right ES of the guinea pig was cauterized aseptically with 10% silver nitrate solution after opening the posterior cranial fossa, and moderate to profound endolymphatic hydrops was consistently produced more than 6 weeks after this treatment ( fig.…”

Endolymphatic Hydrops after Total Dissection or Cauterization of the Distal Portion of the Endolymphatic Sac

“…This group represents the ears in which the sac was cauterized. Although the use of crystallized silver nitrate in our study appeared to provide a better controlled procedure than using a solution of silver nitrate as was used in an earlier study [8], it was very difficult to establish a standardized cauterization of the sac. In some cases, the silver nitrate rapidly spread out following a short and slight touch to the endolymphatic sac, some times even to the intraosseous portion of the endolym phatic sac.…”

Effect of Urea on Endolymphatic Hydrops in Guinea Pigs

“…Two g/kg of urea were administered intra venously to the guinea pigs with endolym phatic hydrops which had been produced 2 months before by injecting a small amount of silver nitrate solution into the endolymphatic sac [11], In 8 guinea pigs (73%) out of 11, membranous collapse was observed after the development of hydrops, extensively in the saccule, moderately in the lower turns of the cochlea and less in the upper turns and the utricle ( fig. 2B, 3B, 4B, 6).…”