Biomaterial Database

[Temporal cochlear changes evoked by prolonged exposure to low intensity noise. Electrophysiological study in guinea pigs]. 1976

L D Benítez

Behavioral temporal threshold shifts (TTS) have been shown in the chinchilla, to be correlated with cochlear microphonic (CM) and whole-nerve action potential (AP) losses in the sensitivity as well as in maximum voltage. The Guinea-pig's ear differs significantly both anatomically and physiologically from the chinchilla's; as a result, it does not seem to be as susceptible to TTS at non-injurious noise levels, except at those frequency bands were middle-ear impedance and other factors are more favorable. At times varying from 2 hrs to 48 hrs after termination of noise exposures of 48 hrs duration to an octave-band of noise (7-14 KHz) with a sound-pressure level of 95 dB, the CM from the first three cochlear turns as well as the whole-nerve AP were measured in Guinea pigs. Losses in sensitivity as well as in maximum voltage were found in the CM recorded from the first turn. CM recovered gradually with time, reaching normal levels at about 40 hrs after termination of noise exposures. The AP +showed similar losses. Microscopic examination of the organ of Corti showed no loss of hair cells.

UI	MeSH Term	Description	Entries
D009622	Noise	Any sound which is unwanted or interferes with HEARING other sounds.	Noise Pollution,Noises,Pollution, Noise
D003056	Cochlear Nerve	The cochlear part of the 8th cranial nerve (VESTIBULOCOCHLEAR NERVE). The cochlear nerve fibers originate from neurons of the SPIRAL GANGLION and project peripherally to cochlear hair cells and centrally to the cochlear nuclei (COCHLEAR NUCLEUS) of the BRAIN STEM. They mediate the sense of hearing.	Acoustic Nerve,Auditory Nerve,Acoustic Nerves,Auditory Nerves,Cochlear Nerves,Nerve, Acoustic,Nerve, Auditory,Nerve, Cochlear,Nerves, Acoustic,Nerves, Auditory,Nerves, Cochlear
D006168	Guinea Pigs	A common name used for the genus Cavia. The most common species is Cavia porcellus which is the domesticated guinea pig used for pets and biomedical research.	Cavia,Cavia porcellus,Guinea Pig,Pig, Guinea,Pigs, Guinea
D006317	Hearing Loss, Noise-Induced	Hearing loss due to exposure to explosive loud noise or chronic exposure to sound level greater than 85 dB. The hearing loss is often in the frequency range 4000-6000 hertz.	Acoustic Trauma,Hearing Loss, Noise Induced,Noise-Induced Hearing Loss
D000161	Acoustic Stimulation	Use of sound to elicit a response in the nervous system.	Auditory Stimulation,Stimulation, Acoustic,Stimulation, Auditory
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D001299	Audiometry	The testing of the acuity of the sense of hearing to determine the thresholds of the lowest intensity levels at which an individual can hear a set of tones. The frequencies between 125 and 8000 Hz are used to test air conduction thresholds and the frequencies between 250 and 4000 Hz are used to test bone conduction thresholds.	Audiometries
D013997	Time Factors	Elements of limited time intervals, contributing to particular results or situations.	Time Series,Factor, Time,Time Factor