Differential functional expression of cation-Cl- cotransporter mRNAs (KCC1, KCC2, and NKCC1) in rat trigeminal nervous system
Differential functional expression of cation-Cl- cotransporter mRNAs (KCC1, KCC2, and NKCC1) in rat trigeminal nervous system
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DOI：
10.1016/j.molbrainres.2004.09.015
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发表时间：
2005-01-05
期刊：
影响因子：
--
通讯作者：
Fukuda, A
中科院分区：
文献类型：
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作者：
Toyoda, H;Yamada, J;Fukuda, A
GABA是成人脑内主要的抑制性神经递质，通过GABA（A）受体引起Cl-内流进入细胞。Cl-流入的方向取决于跨膜的Cl-梯度。氯离子共转运蛋白在神经元胞内氯离子浓度（[Cl-]）的调控中起着关键作用，因此，它们调节GABA能的功能。为了阐明这些协同转运体在三叉神经核中的分布，我们用原位杂交组织化学方法研究了K+-Cl-协同转运体（KCC 1和KCC 2）和Na+-K+-2Cl（-）协同转运体（NKCC 1）mRNA的表达。KCC 2 mRNA在三叉神经运动核（Mo 5）、三叉神经主核（Pr 5）和三叉神经脊束核（Sp 5）有表达，而在三叉神经节（TG）和三叉神经中脑核（Me 5）无表达。另一方面，KCC 1和NKCC 1 mRNA在所有三叉神经核中表达。Me 5神经元静息态[Cl-]i显著高于Mo 5神经元。因此，在初级感觉神经元如TG和Me 5中，[Cl-]（i）将高于其他三叉神经核，因为缺乏KCC 2 mRNA表达。由于Me 5神经元对GABA的反应是去极化的，而Mo 5神经元对GABA的反应是去极化的，因此GABA在三叉神经核和TG中具有不同的生理功能。(C)2004 Elsevier B. V.保留所有权利。
GABA is the main inhibitory neurotransmitter in the adult brain, which causes Cl- influx into the cell via GABA(A) receptors. The direction of Cl- inflow is dependent on the Cl- gradient across the membrane. Cation-Cl- cotransporters have been considered to play pivotal roles in controlling intracellular Cl- concentration ([Cl-]) of neurons; hence, they modulate the GABAergic function. To elucidate how these cotransporters are distributed in the trigeminal nuclei, we investigated the expressions of K+-Cl- cotransporters (KCC1 and KCC2) and Na+-K+-2Cl(-) cotransporter (NKCC1) mRNAs by using in situ hybridization histochemistry. KCC2 mRNA was expressed in the motor trigerninal nucleus (Mo5), the principal trigeminal nucleus (Pr5), and the spinal trigeminal nucleus (Sp5), but not in the trigeminal ganglion (TG) and the mesencephalic trigeminal nucleus (Me5). On the other hand, KCC1 and NKCC1 mRNAs were expressed in all the trigeminal nuclei. The resting [Cl-]i of Me5 neurons was significantly higher than that of Mo5 neurons. Thus, in primary sensory neurons such as the TG and the Me5, [Cl-](i) would be higher than those in the other trigeminal nuclei because of the lack of KCC2 mRNA expression. Since Me5 neurons, but not Mo5 neurons, responded to GABA by depolarization, GABA would have differential physiological functions among trigeminal nuclei and TG. (C) 2004 Elsevier B.V. All rights reserved.