Kelly J B, Kidd S A
Laboratory of Sensory Neuroscience, Institute of Neuroscience and Department of Psychology, Carleton University, Ottawa, Ontario K1S 5B6, Canada.
J Neurophysiol. 2000 Mar;83(3):1403-14. doi: 10.1152/jn.2000.83.3.1403.
Binaural responses of single neurons in the rat's central nucleus of the inferior colliculus (ICC) were recorded before and after local injection of excitatory amino acid receptor antagonists (either 1,2, 3,4-tetrahydro-6-nitro-2,3-dioxo-benzo[f]quinoxaline-7-sulfonamide disodium [NBQX], (+/-)-3-(2-carboxypiperazin-4-yl)-propyl-1-phosphonic acid [CPP], 6-cyano-7-nitroquinoxaline-2,3-dione [CNQX], or (+/-)-2amino-5-phosphonovaleric acid [APV]) into the dorsal nucleus of the lateral lemniscus (DNLL). Responses were evoked by clicks delivered separately to the two ears at interaural time delays between -1.0 and +30 ms (positive values referring to ipsilateral leading contralateral click pairs). The neurons in our sample were excited by contralateral stimulation and inhibited by ipsilateral stimulation, and the probability of action potentials was reduced as the ipsilateral stimulus was advanced. Binaural inhibition resulted in response suppression that lasted up to 30 ms. Injection of excitatory amino acid antagonists into the DNLL contralateral to the recording site reduced the strength of binaural inhibition in the ICC. The alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor antagonist NBQX preferentially affected responses at small interaural time intervals (0-1.0 ms), whereas the N-methyl-D-aspartate (NMDA) antagonist CPP preferentially affected responses at longer intervals (1-30 ms). Both CNQX and APV produced a release from binaural inhibition, but neither drug was selective for specific intervals. The data support the idea that binaural inhibition in the rat ICC is influenced by both AMPA and NMDA receptor-mediated excitatory events in the contralateral DNLL. The results suggest that the AMPA receptors contribute selectively to the initial component of binaural inhibition and the NMDA receptors to a longer lasting component.
在大鼠下丘中央核（ICC）中，对单个神经元的双耳反应进行了记录，记录时间分别为向外侧丘系背核（DNLL）局部注射兴奋性氨基酸受体拮抗剂（1,2,3,4 - 四氢 - 6 - 硝基 - 2,3 - 二氧代 - 苯并[f]喹喔啉 - 7 - 磺酰胺二钠[NBQX]、(±)-3-(2 - 羧基哌嗪 - 4 - 基)-丙基 - 1 - 膦酸[CPP]、6 - 氰基 - 7 - 硝基喹喔啉 - 2,3 - 二酮[CNQX]或(±)-2 - 氨基 - 5 - 膦基戊酸[APV]）之前和之后。通过在双耳间时间延迟为 -1.0至 +30毫秒（正值表示同侧领先对侧的点击对）时分别向两只耳朵发送点击来诱发反应。我们样本中的神经元受到对侧刺激的兴奋，并受到同侧刺激的抑制，并且随着同侧刺激提前，动作电位的概率降低。双耳抑制导致反应抑制持续长达30毫秒。向记录部位对侧的DNLL注射兴奋性氨基酸拮抗剂会降低ICC中双耳抑制的强度。α - 氨基 - 3 - 羟基 - 5 - 甲基 - 4 - 异恶唑丙酸（AMPA）受体拮抗剂NBQX在小双耳间时间间隔（0 - 1.0毫秒）时优先影响反应，而N - 甲基 - D - 天冬氨酸（NMDA）拮抗剂CPP在较长时间间隔（1 - 30毫秒）时优先影响反应。CNQX和APV都能解除双耳抑制，但两种药物对特定时间间隔都没有选择性。数据支持这样的观点，即大鼠ICC中的双耳抑制受对侧DNLL中AMPA和NMDA受体介导的兴奋性事件的影响。结果表明，AMPA受体选择性地参与双耳抑制的初始成分，而NMDA受体参与持续时间更长的成分。
