GABAergic neurons in inferior colliculus of the GAD67-GFP knock-in mouse: Electrophysiological and morphological properties
GABAergic neurons in inferior colliculus of the GAD67-GFP knock-in mouse: Electrophysiological and morphological properties
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DOI：
10.1016/j.neures.2004.12.019
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发表时间：
2005-04-01
影响因子：
2.9
通讯作者：
Koyano, K
中科院分区：
文献类型：
--
作者：
Ono, M;Yanagawa, Y;Koyano, K
利用GAD 67-GFP基因敲入小鼠脑片，用GFP荧光标记GABA能神经元，采用全细胞膜片钳记录结合生物素胞内染色技术，研究了下丘GABA能神经元的电生理特性。IC的GABA能神经元分为两种不同的放电类型：（1）紧张型神经元和（2）瞬时（相位）型神经元。强直型神经元对长去极化电流脉冲（200 ms）表现出规律性的重复放电模式，瞬时型神经元在电流脉冲开始时表现出棘波放电。这两种类型的神经元大多数在超极化电流脉冲下表现出去极化下垂，这一现象可被0.1 mM ZD 7288（I-h阻断剂）阻断。所有两种类型的紧张性神经元都显示出AHP，这被Cd 2（+）（0.1 mM）和高浓度的aparnin（2 μ M）所阻断。其中一个紧张型神经元（BP）在超极化电位刺激下，放电起始延迟较长或首次放电间隔较长。其余的强直神经元（RS）没有表现出这种特性。紧张型神经元分布于下丘各区。形态学上，他们是不相同的，异构体直径，树突领域的大小和方向。其中一个瞬时型神经元（Th-）在放电后出现AHP。其它瞬时型神经元（Th+）在放电后出现去极化峰，可被0.1- 0.2mMNi ~（2+）阻断。Th+型神经元仅见于IC背外侧区，树突野较小。Th+1型神经元可能是IC中GABA能神经元的一个独特的同质群。(c)2005年Elsevier爱尔兰有限公司和日本神经科学学会。All rights reserved.
Utilizing slice preparations of GAD67-GFP knock-in mouse, in which GABAergic neurons are specifically labeled with GFP fluorescence, we studied electrophysiological characteristics of GABAergic neurons of IC by whole-cell patch clamp-recording combined with biocytinintracellular-staining techniques. GABAergic neurons of IC fell into two distinct firing types; (1) tonic type neurons and (2) transient (phasic) type neurons. Tonic type neurons showed regularly repetitive discharge pattern in response to a long depolarizing current pulse (200 ms), and transient type neurons showed spike discharges just at the onset of current pulse. Most of neurons of both types showed depolarizing sag in response to hyperpolarizing current pulse, which were blocked by 0.1 mM ZD7288 (I-h blocker). All two types of tonic neurons showed an AHP, which was blocked by Cd2(+) (0.1 mM) and high concentration of aparnin (2 mu M). One of tonic type neurons (BP) revealed a long delay in spike onset or a longer first spike interval when they were stimulated from hyperpolarized potentials. The remaining tonic neurons (RS) did not show this property. Tonic type neurons were distributed in all region of IC. Morphologically, they were not identical; heterogeneous in somatic diameter, dendritic field size and its orientation. One of transient type neurons (Th-) revealed an AHP after the spike. The other transient type neurons (Th+) showed a depolarization hump after the spike, which were blocked by 0.1-0.2 mM Ni2+. Th+ type neurons were found only in the dorsolateral region of IC, having small dendritic field. Th+, type neurons are likely to be a distinct, homogenous group of GABAergic neuron in IC. (c) 2005 Elsevier Ireland Ltd and the Japan Neuroscience Society. All rights reserved.