Malfunction of respiratory-related neuronal activity in Na+, K+-ATPase α2 subunit-deficient mice is attributable to abnormal Cl- homeostasis in brainstem neurons
Malfunction of respiratory-related neuronal activity in Na+, K+-ATPase α2 subunit-deficient mice is attributable to abnormal Cl- homeostasis in brainstem neurons
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DOI：
10.1523/jneurosci.2909-04.2004
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发表时间：
2004-11-24
影响因子：
5.3
通讯作者：
Kawakami, K
中科院分区：
文献类型：
--
作者：
Ikeda, K;Onimaru, H;Kawakami, K
Na+，K+-ATP酶α 2亚基基因（Atp 1a 2）敲除纯合子小鼠（Atp 1a 2（-/-））出生后立即因呼吸缺乏而死亡。用脑干-脊髓整体标本研究Atp 1a 2（-/-）中与突触相关的神经元活动。呼吸运动神经元的活动记录从第四颈前根（C4）是有缺陷的Atp 1a 2（-/-）胚胎18.5天的胎儿。在Krebs液灌流过程中，Atp 1a 2（-/-）大鼠对延髓腹外侧区（VLM）电刺激的C4反应恢复慢于野生型大鼠，这与Atp 1a 2（-/-）大鼠脑内高浓度的细胞外GABA一致。光学记录显示Atp 1a 2（-/-）的VLM缺乏抑制性神经活动。在短杆菌肽穿孔膜片钳记录中，Atp 1a 2（-/-）VLM的神经元内Cl-浓度较高。α 2亚基和神经元特异性K-Cl协同转运蛋白KCC 2在野生型胎儿的纯化突触膜部分中共免疫沉淀。基于这些结果，我们提出了一个模型的Na+，K+-ATP酶α 2亚基和KCC 2，排除Cl-从呼吸中枢神经元胞质溶胶之间的功能耦合。
Na+, K+-ATPase alpha2 subunit gene (Atp1a2) knock-out homozygous mice (Atp1a2(-/-)) died immediately after birth resulting from lack of breathing. The respiratory-related neuron activity in Atp1a2(-/-) was investigated using a brainstem-spinal cord en bloc preparation. The respiratory motoneuron activity recorded from the fourth cervical ventral root (C4) was defective in Atp1a2(-/-) fetuses of embryonic day 18.5. The C4 response to electrical stimulation of the ventrolateral medulla (VLM) recovered more slowly in Atp1a2(-/-) than in wild type during superfusion with Krebs' solution, consistent with the high extracellular GABA in brain of Atp1a2(-/-). Lack of inhibitory neural activities in VLM of Atp1a2(-/-) was observed by optical recordings. High intracellular Cl- concentrations in neurons of theVLMof Atp1a2(-/-) were detected in gramicidin-perforated patch-clamp recordings. The alpha2 subunit and a neuron-specific K-Cl cotransporter KCC2 were coimmunoprecipitated in a purified synaptic membrane fraction of wild-type fetuses. Based on these results, we propose a model for functional coupling between the Na+, K+-ATPase alpha2 subunit and KCC2, which excludes Cl- from the cytosol in respiratory center neurons.