Electrophysiological evaluation of chloroform-induced inner ear damage

• Published in: Archives of Oto-Rhino-Laryngology 1987-01, Vol.244 (4), p.222-228
• Main Authors: HU, K, SCHWARZ, D. W. F
• Format: Article
• Language: English
• Subjects: Animals; Audiometry, Evoked Response; Biological and medical sciences; Chloroform - administration & dosage; Chloroform - adverse effects; Cochlea - drug effects; Cochlea - physiopathology; Deafness - chemically induced; Deafness - physiopathology; Drug toxicity and drugs side effects treatment; Ear, Middle - drug effects; Ear, Middle - pathology; Guinea Pigs; Labyrinth Diseases - chemically induced; Labyrinth Diseases - physiopathology; Medical sciences; Miscellaneous (drug allergy, mutagens, teratogens...); Pharmacology. Drug treatments; Rats; Rats, Inbred Strains; Vestibule, Labyrinth - drug effects
• ISSN: 0302-9530; 1434-4726
• DOI: 10.1007/BF00455310

Local placement of chloroform in either the external or the middle ear has been previously reported to induce a chemical labyrinthectomy. In order to examine the value of this effect as a research tool, we injected chloroform into the middle ears of guinea pigs and rats. Cochlear damage was assessed by electrocochleography (ECochG) and auditory brainstem response (ABR) audiometry. Both species developed complete deafness within a few hours after instillation of the chloroform. The deafness was permanent in the guinea pigs, whereas there was a partial recovery of auditory function in the rats. The survival rate of the auditory nerve fibers was estimated by measuring the ABR evoked by electrical stimulation via the scala tympani (EABR). A normal EABR recruitment pattern suggested that the main chloroform effect was located peripheral to the afferent axons. In conclusion, chloroform must be considered a severely ototoxic agent when applied locally.