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Toluene effect on the olivocochlear reflex
- Source :
- Toxicological sciences : an official journal of the Society of Toxicology. 121(1)
- Publication Year :
- 2011
-
Abstract
- Animal studies have shown that toluene can cause hearing loss and can exacerbate the effects of noise by inhibiting the middle ear acoustic reflex. In this investigation, carried out in Long-Evans rats, the tensor tympani tendon was cutoff and the stapedius muscle was electrocoagulated in one or both middle ears. Rat hearing was evaluated by measuring cubic distortion otoacoustic emissions (2f1-f2; f1 5 8000 Hz; f2 5 9600 Hz; f1/f2 5 1.2) prior to, during, and after activation of the olivocochlear (OC) reflex. A band noise centered at 4 kHz was used as suppressor noise. It was delivered contralaterally to decrease 2f1-f2 amplitude. The strength of the inner ear acoustic reflex was tested by increasing contralateral noise intensity, and toluene injected into the carotid artery was used to study physiological efficacy. Results showed that the protective effect of the OC reflex is intensity dependent. In addition, the OC reflex was found to be less sensitive to toluene than the middle ear acoustic reflex. This may be because the efferent neurons involved in inner ear and middle ear reflexes are located differently. In conclusion, the synergistic effects on hearing of co-exposure to noise and aromatic solvents are because of solvents depressing the central nuclei, which mainly drive the middle ear acoustic reflex.
- Subjects :
- medicine.medical_specialty
Hearing loss
Chemistry
Audiology
Toxicology
Stapedius muscle
Intensity (physics)
Cochlea
Rats
Noise
medicine.anatomical_structure
Reflex
otorhinolaryngologic diseases
medicine
Middle ear
Animals
Inner ear
Rats, Long-Evans
sense organs
medicine.symptom
Acoustic reflex
Hearing Loss
Toluene
Subjects
Details
- ISSN :
- 10960929
- Volume :
- 121
- Issue :
- 1
- Database :
- OpenAIRE
- Journal :
- Toxicological sciences : an official journal of the Society of Toxicology
- Accession number :
- edsair.doi.dedup.....6f714b1ad58b77a34cd95cea9b23d859