中国神经再生研究(英文版) ›› 2014, Vol. 9 ›› Issue (4): 420-429.doi: 10.4103/1673-5374.128250

• 原著:脑损伤修复保护与再生 • 上一篇    下一篇

γ-氨基丁酸局部抑制可延长下丘脑听觉中的优先效应

  

  • 收稿日期:2013-02-26 出版日期:2014-02-25 发布日期:2014-02-25
  • 基金资助:

    国家自然科学基金项目(No. 81271090);北京市自然科学基金项目(No. 7112055)

Local inhibition of GABA affects precedence effect in the inferior colliculus

Yanjun Wang1, Ningyu Wang1, Dan Wang1, Jun Jia2, Jinfeng Liu1, Yan Xie2, Xiaohui Wen1, Xiaoting Li1   

  1. 1 Department of Otorhinolaryngology Head and Neck Surgery, Beijing Chaoyang Hospital, Capital Medical University, Beijing, China
    2 Department of Neurophysiology, Capital Medical University, Beijing, China
  • Received:2013-02-26 Online:2014-02-25 Published:2014-02-25
  • Contact: Ningyu Wang, M.D., Department of Otorhinolaryngology Head and Neck Surgery, Beijing Chaoyang Hospital, Capital Medical University, Beijing 100020; College of Otolaryngology, Capital Medical University, Beijing 100069, China; Key Laboratory of Otolaryngology Head and Neck Surgery, Capital Medical University, Ministry of Education, Beijing 100069, China, wny0108@hotmail.com.
  • Supported by:

    This work was supported by the National Natural Science Foundation of China, No. 81271090 and the Beijing Natural Science Foundation, No. 7112055.

摘要:

下丘脑中具有较多的γ-氨基丁酸阳性神经纤维末梢,与许多听觉中枢调节通路密切相关。实验以微电泳给药方法给予健康大鼠在下丘脑局部注射γ-氨基丁酸,用40ms白噪音探测到单个神经元单位,然后给予不同刺激间隔成对短白噪声刺激大鼠,细胞外记录结果共记录到50个神经元单位,其中36个表现为对回声压制现象。在局部微量注射γ-氨基丁酸后,下丘脑神经元对滞后声的标准化反应降低,半极大刺激间隔时间增加,对滞后声的恢复时间延长。无论领先声和/或滞后声处于记录点对侧或者同侧,这种效应在均存在。结果提示γ-氨基丁酸局部抑制可降低神经元对成对滞后刺激声的反应,延长对滞后声的压制时间和恢复时间。

关键词: 神经再生, 优先效应, 听觉中枢, 下丘脑, γ-氨基丁酸, 局部抑制, 回声压制, 滞后刺激, 基金资助项目

Abstract:

The precedence effect is a prerequisite for faithful sound localization in a complex auditory environment, and is a physiological phenomenon in which the auditory system selectively suppresses the directional information from echoes. Here we investigated how neurons in the inferior colliculus respond to the paired sounds that produce precedence-effect illusions, and whether their firing behavior can be modulated through inhibition with gamma-aminobutyric acid (GABA). We recorded extracellularly from 36 neurons in rat inferior colliculus under three conditions: no injection, injection with saline, and injection with gamma-aminobutyric acid. The paired sounds that produced precedence effects were two identical 4-ms noise bursts, which were delivered contralaterally or ipsilaterally to the recording site. The normalized neural responses were measured as a function of different inter-stimulus delays and half-maximal interstimulus delays were acquired. Neuronal responses to the lagging sounds were weak when the inter-stimulus delay was short, but increased gradually as the delay was lengthened. Saline injection produced no changes in neural responses, but after local gamma-aminobutyric acid application, responses to the lagging stimulus were suppressed. Application of gamma-aminobutyric acid affected the normalized response to lagging sounds, independently of whether they or the paired sounds were contralateral or ipsilateral to the recording site. These observations suggest that local inhibition by gamma-aminobutyric acid in the rat inferior colliculus shapes the neural responses to lagging sounds, and modulates the precedence effect.

Key words: nerve regeneration, precedence effect, auditory center, inferior colliculus, gamma-aminobutyric acid, local inhibition, echo suppression, lagging stimulus, NSFC grant, neural regeneration