Electrocochleographic Evaluation of the Guinea Pig Model of Endolymphatic Hydrops

• Published in: Annals of otology, rhinology & laryngology Vol. 106; no. 11; pp. 934 - 942
• Main Authors: Badr-El-Dine, Mohamed, Gerken, George M., Robinson, Karen S., Wright, Charles G., Meyerhoff, William L.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Los Angeles, CA SAGE Publications 01.11.1997; Annals Publishing Compagny; SAGE PUBLICATIONS, INC
• Subjects: Action Potentials; Animals; Audiometry, Evoked Response - methods; Auditory Threshold; Biological and medical sciences; Dehydration - complications; Disease Models, Animal; Endolymphatic Hydrops - chemically induced; Endolymphatic Hydrops - diagnosis; Female; Glycerol; Guinea Pigs; Investigative techniques, diagnostic techniques (general aspects); Male; Medical sciences; Meniere Disease - physiopathology; Osmolar Concentration; Otorhinolaryngology functional investigation (larynx, voice, audiometry, vestibular function, equilibration...); Recruitment, Neurophysiological; Reproducibility of Results; Urea; guinea pig; Meniere's disease; dehydration; summating potential; action potential; endolymphatic hydrops; Induction; Internal ear disease; Rodentia; Exploration; Action potential; Anasarca; Experimental study; Summating potential; Electrodiagnosis; Vertebrata; Endolymph; Mammalia; Guinea pig; Electrocochleography; Animal; ENT disease; Meniere disease
• ISSN: 0003-4894; 1943-572X
• DOI: 10.1177/000348949710601109

Electrocochleography (ECochG) was used to evaluate cochlear function in guinea pigs with experimentally induced endolymphatic hydrops (ELH) before and after osmotic dehydration with either glycerol or urea. We surgically induced ELH in the right ears of 9 guinea pigs, while the right ears of 6 guinea pigs received a sham operation. The left ears of the 15 animals constituted the normal group. Eight weeks after surgery, summating potential (SP) and action potential (AP) amplitudes were measured prior to and following the administration of glycerol or urea. The SPs and SP/AP ratios were reduced in all groups, with no significant differences among groups or between dehydrating agents. Some of the hydropic ears, however, did show an increased AP threshold and a recruitment effect. In measurements from 6 additional animals, serum osmolarity increased more with urea than with glycerol. The guinea pig model remains valuable for investigation of ELH, even though it differs in significant respects from ELH in humans.