EFFECT OF EXOGENOUS GLUTAMATE ON COMPOUND ACTION POTENTIAL (CAP) AND COCHLEAR MICROPHONICS (CM) OF GUINEA PIG′S COCHLEA
- VernacularTitle:外源性谷氨酸对豚鼠耳蜗复合动作电位及微音电位的影响
- Author:
Ning YU
;
Jun LIU
;
Zuli TAN
- Publication Type:Journal Article
- Keywords:
glutamic acid;
perfusion;
cochlea;
guinea pigs
- From:
Medical Journal of Chinese People's Liberation Army
1982;0(03):-
- CountryChina
- Language:Chinese
-
Abstract:
To investigate the changes in CAP and CM recorded from the cochlear round window when glutamate solution in different concentrations(10mmol/L, 5mmol/L, 1mmol/L) was instilled into whole cochlea perilymph. The results demonstrated that there was a dependent correlation between CAP threshold shift and glutamate concentration. CAP threshold shift and amplitude could be markedly influenced by glutamate instillation. However, amplitude of CM was not obviously affected, and the I/O function of CM amplitude always maintained a nonlinear characteristic. The results suggest that glutamate has selective effects between inner hair cells and outer hair cells. High concentration glutamate might cause an increase in intracellular calcium, even as high as to induce toxicity. It could be induced by glutamate when it acts on IHC′s presynaptic autoreceptor in positive feedback manner, or on the afferent neurons, so that the synapsis is directly damaged by glutamate concentration overload in synaptic cleft.
