Biomaterial Database

Effects of high intensity impulse noise on ionic concentrations in cochlear endolymph of the guinea pig. 1997

W Li, and L Zhao, and S Jiang, and R Gu

Institute of Otolaryngology, Chinese PLA General Hospital, Beijing, China.

OBJECTIVE To investigate the effect of acoustic overstimulation on concentrations of cations in cochlear endolymph and analyze the relationship between the ionic changes in endolymph and the hearing loss. METHODS The endocochlear potentials (EP), K+, Na+ and Ca2+ concentration in cochlear endolymph were examined in vivo for normal and 167 +/- 2 dB SPL impulse noise exposed groups of guinea pig bored on time course by means of double-barreled ion-selective microelectrodes. Brain stem auditory evoked potential (BAEP) was used to evaluate the auditory function. Ca(2+)-ATPase activity was demonstrated cytochemically in the lateral cochlear wall as induced by Ando et al with slight modification. RESULTS The K+ and Ca2+ concentration exhibited significant changes in 8-hour groups (P < 0.05 for K+ and P < 0.01 for Ca2+). Then the K+ concentration was eventually resumed to the initial levels in accordance with the EP recovery in 7 days, while during the same period Ca2+ concentration was always significantly higher than that in control group (P < 0.01). The BAEP threshold shifts were correlated well with changes in ionic concentrations, especially Ca2+ (P < 0.001), in the endolymph induced by acoustic trauma. Although the normal positive EP was observed 7 days after noise exposure, the function of the vascular stria was not completely restored as revealed by the fact that the Ca(2+)-ATPase was diffused to the apical membrane surface. CONCLUSIONS Endolymph compartment intrinsic mechanism for maintaining ionic composition is seriously deteriorated after high impulse noise stimulation. The changes of the unique environment of endolymph may play an important role in the mechanism of sensorineural hearing loss induced by acoustic trauma.

UI	MeSH Term	Description	Entries
D009622	Noise	Any sound which is unwanted or interferes with HEARING other sounds.	Noise Pollution,Noises,Pollution, Noise
D011188	Potassium	An element in the alkali group of metals with an atomic symbol K, atomic number 19, and atomic weight 39.10. It is the chief cation in the intracellular fluid of muscle and other cells. Potassium ion is a strong electrolyte that plays a significant role in the regulation of fluid volume and maintenance of the WATER-ELECTROLYTE BALANCE.
D011897	Random Allocation	A process involving chance used in therapeutic trials or other research endeavor for allocating experimental subjects, human or animal, between treatment and control groups, or among treatment groups. It may also apply to experiments on inanimate objects.	Randomization,Allocation, Random
D002118	Calcium	A basic element found in nearly all tissues. It is a member of the alkaline earth family of metals with the atomic symbol Ca, atomic number 20, and atomic weight 40. Calcium is the most abundant mineral in the body and combines with phosphorus to form calcium phosphate in the bones and teeth. It is essential for the normal functioning of nerves and muscles and plays a role in blood coagulation (as factor IV) and in many enzymatic processes.	Coagulation Factor IV,Factor IV,Blood Coagulation Factor IV,Calcium-40,Calcium 40,Factor IV, Coagulation
D003051	Cochlea	The part of the inner ear (LABYRINTH) that is concerned with hearing. It forms the anterior part of the labyrinth, as a snail-like structure that is situated almost horizontally anterior to the VESTIBULAR LABYRINTH.	Cochleas
D004710	Endolymph	The lymph fluid found in the membranous labyrinth of the ear. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)	Endolymphs
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
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
D016057	Evoked Potentials, Auditory, Brain Stem	Electrical waves in the CEREBRAL CORTEX generated by BRAIN STEM structures in response to auditory click stimuli. These are found to be abnormal in many patients with CEREBELLOPONTINE ANGLE lesions, MULTIPLE SCLEROSIS, or other DEMYELINATING DISEASES.	Acoustic Evoked Brain Stem Potentials,Auditory Brain Stem Evoked Responses,Brain Stem Auditory Evoked Potentials,Evoked Responses, Auditory, Brain Stem,Acoustic Evoked Brain Stem Potential,Acoustic Evoked Brainstem Potential,Acoustic Evoked Brainstem Potentials,Auditory Brain Stem Evoked Response,Auditory Brain Stem Response,Auditory Brain Stem Responses,Auditory Brainstem Evoked Response,Auditory Brainstem Evoked Responses,Auditory Brainstem Responses,Brain Stem Auditory Evoked Potential,Brainstem Auditory Evoked Potential,Brainstem Auditory Evoked Potentials,Evoked Potential, Auditory, Brainstem,Evoked Potentials, Auditory, Brainstem,Evoked Response, Auditory, Brain Stem,Evoked Response, Auditory, Brainstem,Evoked Responses, Auditory, Brainstem,Auditory Brainstem Response,Brainstem Response, Auditory,Brainstem Responses, Auditory,Response, Auditory Brainstem,Responses, Auditory Brainstem