体外培养的小鼠耳蜗核中兴奋性氨基酸作为听神经递质的证据。

Evidence for an excitatory amino acid as the transmitter of the auditory nerve in the in vitro mouse cochlear nucleus.

作者信息

Martin M R

出版信息

Hear Res. 1985;20(3):215-20. doi: 10.1016/0378-5955(85)90026-7.

Abstract

Microionophoretically applied excitatory amino acids induced firing of extracellularly recorded single units in a tissue slice preparation of the mouse cochlear nucleus, and the similarly applied antagonist 2-amino-5-phosphonovalerate (2APV) was demonstrated to be a selective N-methyl-D-aspartate (NMDA) receptor antagonist. In addition, the effect of various bath-applied excitatory amino acid receptor antagonists on auditory nerve evoked field potentials was studied. Antagonists which block NMDA type receptors, blocked auditory nerve evoked potentials in a dose-dependent manner. The 50% effective concentration (EC50) for three of the antagonists used was: D-alpha-aminoadipate, 7.8 mM; 2APV, 4.2 mM; and 2,3-cis-piperidine dicarboxylate, 1.1 mM. Glutamate diethylester (5 mM) had no effect. The results suggest that NMDA, kainate and quisqualate receptors are present in the cochlear nucleus and that auditory nerve transmission in the mouse is mediated by an NMDA type receptor. This is consistent with the concept that the auditory nerve postsynaptic receptor in mammals is of the NMDA type.

摘要

微量离子电泳施加的兴奋性氨基酸可诱导小鼠耳蜗核组织切片标本中细胞外记录的单个神经元放电，并且已证明同样施加的拮抗剂2-氨基-5-磷酸戊酸（2APV）是一种选择性N-甲基-D-天冬氨酸（NMDA）受体拮抗剂。此外，研究了各种浴槽施加的兴奋性氨基酸受体拮抗剂对听神经诱发场电位的影响。阻断NMDA型受体的拮抗剂以剂量依赖方式阻断听神经诱发电位。所用的三种拮抗剂的50%有效浓度（EC50）分别为：D-α-氨基己二酸，7.8 mM；2APV，4.2 mM；以及2,3-顺式哌啶二羧酸，1.1 mM。谷氨酸二乙酯（5 mM）无作用。结果表明，NMDA、海人藻酸和quisqualate受体存在于耳蜗核中，并且小鼠的听神经传递由NMDA型受体介导。这与哺乳动物听神经突触后受体为NMDA型的概念一致。