The roles of GABAergic and glycinergic inhibition on binaural processing in the dorsal nucleus of the lateral lemniscus of the mustache bat.
The roles of GABAergic and glycinergic inhibition on binaural processing in the dorsal nucleus of the lateral lemniscus of the mustache bat.
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DOI：
10.1152/jn.1994.71.6.1999
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发表时间：
1994
影响因子：
2.5
通讯作者：
Lichuan Yang;G. Pollak
中科院分区：
文献类型：
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作者：
Lichuan Yang;G. Pollak
1.我们研究了99个神经元的单耳和双耳的反应特性的背核的外侧丘系（DNLL）的胡子蝙蝠之前和期间的离子电渗应用的拮抗剂，阻断γ-氨基丁酸-A（GABAA）受体（荷包牡丹碱）或甘氨酸受体（士的宁）。所有的细胞都是由对侧耳的单耳刺激驱动的，而同侧耳的单耳刺激从未引起放电。双耳属性的81个神经元的确定，通过保持强度恒定在对侧耳和提出各种强度的同侧耳。这个程序产生的耳间强度差异（IID）的功能，并允许我们确定同侧诱发抑制对侧耳引起的恒定兴奋性驱动的影响。2.主要发现之一是，在大多数DNLL神经元的IID功能不受士的宁或荷包牡丹碱的应用。阻断甘氨酸抑制士的宁没有影响的IID功能在75%的细胞研究。然而，士的宁确实改变了大约25%的DNLL人群的IID功能。在这些细胞中，甘氨酸能抑制似乎是部分，或在少数情况下，完全负责同侧诱发的尖峰抑制。与此相反，阻断GABA能抑制荷包牡丹碱对同侧诱发的尖峰抑制在任何兴奋性/抑制性细胞，我们记录没有明显的影响。因此，GABA能抑制在DNLL神经元IID功能的形成中不起作用。此外，结果表明，甘氨酸能抑制也不有助于抑制刺激对侧耳诱发的尖峰在绝大多数DNLL神经元。3.虽然大多数的IID功能没有受到影响时，无论是GABA能或甘氨酸能神经支配被阻断，同侧刺激单独诱发大多数DNLL细胞的甘氨酸能和GABA能抑制。这些抑制事件被证明在18个其他细胞引起的放电与离子电渗应用谷氨酸。在这些条件下单独刺激同侧耳引起谷氨酸诱发放电的抑制。此外，尖峰抑制持续的时间比同侧耳的短纯音的持续时间更长。4.荷包牡丹碱和士的宁对谷氨酸诱发的峰电位有不同的影响。荷包牡丹碱可缩短抑制作用的持续时间，并且荷包牡丹碱总是在抑制作用的后半部分消除抑制作用。在超过一半的细胞研究士的宁也减少了持续时间的抑制。（400字处截断摘要）
1. We studied the monaural and binaural response properties of 99 neurons in the dorsal nucleus of the lateral lemniscus (DNLL) of the mustache bat before and during the iontophoretic application of antagonists that blocked gamma-aminobutyric acid-A (GABAA) receptors (bicuculline) or glycine receptors (strychnine). All cells were driven by monaural stimulation of the contralateral ear, whereas monaural stimulation of the ipsilateral ear never evoked discharges. The binaural properties of 81 neurons were determined by holding the intensity constant at the contralateral ear and presenting a variety of intensities to the ipsilateral ear. This procedure generated interaural intensity disparity (IID) functions and allowed us to determine the effect of ipsilaterally evoked inhibition on a constant excitatory drive evoked by the contralateral ear. 2. One of the main findings is that the IID functions in the majority of DNLL neurons were not affected by application of either strychnine or bicuculline. Blocking glycinergic inhibition with strychnine had no effect on the IID functions in 75% of the cells studied. However, strychnine did change the IID functions in approximately 25% of the DNLL population. In those cells glycinergic inhibition appeared to be partially, or, in a few cases, entirely responsible for the ipsilaterally evoked spike suppression. In contrast, blocking GABAergic inhibition with bicuculline had no discernible effect on the ipsilaterally evoked spike suppression in any of the excitatory/inhibitory cells that we recorded. GABAergic inhibition, therefore, plays no role in the formation of IID functions of neurons in the DNLL. Furthermore, the results suggest that glycinergic inhibition also does not contribute to the suppression of spikes evoked by stimulation of the contralateral ear in the vast majority of DNLL neurons. 3. Although the majority of IID functions were not influenced when either GABAergic or glycinergic innervation was blocked, ipsilateral stimulation alone evoked both a glycinergic and GABAergic inhibition in most DNLL cells. These inhibitory events were demonstrated in 18 other cells by evoking discharges with the iontophoretic application of glutamate. Stimulating the ipsilateral ear alone under these conditions caused a suppression of the glutamate-evoked discharges. Furthermore, the spike suppression persisted for a period of time that was longer than the duration of the tone burst at the ipsilateral ear. 4. The application of bicuculline or strychnine had different effects on the glutamate-elicited spikes. Bicuculline reduced the duration of the inhibition, and it was always the latter portion of the inhibition that was abolished by bicuculline. In more than half of the cells studied strychnine also reduced the duration of the inhibition.(ABSTRACT TRUNCATED AT 400 WORDS)