[Level of glutamate on the auditory pathway of inferior colliculus after exposure to noise observed by microdialysis in vivo].
OBJECTIVE
To explore the quality and quantity of glutamate(Glu) on the auditory pathway of inferior colliculus when exposed to conditioning noise or traumatic sound to find the relationship between the change of neurotransmitters and the protection of hearing, and the mechanism in the phenomena.


METHODS
Twenty Sprague-Dawley rats were divided into four groups: control group, conditioning group, intensive noise group and combining group. The hearing function was measured by ABR. Glu was detected by microdialysis and HPLC.


RESULTS
The ABR levels after exposure were (47.0+/-2.7) dB SPL (intensive noise group ),(31.0+/-2.2) dB SPL (conditioning group ) and (36.0+/-2.2) dB SPL (combining group ).The levels of Glu were (310.5+/-78.5)x 10(-7)mol/L (intense noise group ),(162.9+/-64.1)x10(-7)mol/L (conditioning group ); (113.6+/-38.1)x10(-7)mol/L (combining group),(56.3+/-23.9)x10(-7)mol/L (control group).


CONCLUSIONS
The level of Glu on the auditory pathway of inferior colliculus was higher when exposed to noise . Glu was exhausted when given conditioning sound, and the level of Glu was lower when given following intense noise. High level of Glu can damage hearing, so exhaustion of Glu in sound condition may contribute to the protection.
Department of Otorhinolaryngology Head and Neck Surgery, Peking University Third hospital, Beijing 100083, China.
Hua Shun
HS
Xie
Wei Ming
WM
Song
Di Hua
DH
Shangguan
Xue Pei
XP
Li
Wei
W
Wang
Li
L
Wang
Li
L
Zhu
D000161:Acoustic Stimulation; D000818:Animals; D001306:Auditory Pathways / Q000378:metabolism* / Q000503:physiopathology; D001309:Auditory Threshold; D016057:Evoked Potentials, Auditory, Brain Stem; D018698:Glutamic Acid / Q000378:metabolism*; D007245:Inferior Colliculi / Q000378:metabolism* / Q000503:physiopathology; D008297:Male; D017551:Microdialysis; D009622:Noise / Q000009:adverse effects*; D051381:Rats; D017207:Rats, Sprague-Dawley
D018698:Glutamic Acid