Direct modulation of GABAA receptor by intracellular ATP in dissociated nucleus tractus solitarii neurones of rat.
Direct modulation of GABAA receptor by intracellular ATP in dissociated nucleus tractus solitarii neurones of rat.
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大鼠孤束核神经元细胞内 ATP 直接调节 GABAA 受体。
DOI：
10.1113/jphysiol.1992.sp019101
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发表时间：
1992
期刊：
影响因子：
--
通讯作者：
Norio Akaike
中科院分区：
文献类型：
--
作者：
Tetsuya Shirasaki;K. Aibara;Norio Akaike
1. 利用膜片钳全细胞模式研究了细胞内ATP对游离孤束核（NTS）神经元中GABA （γ -氨基丁酸）受体亚型GABAA介导的Cl -电流（ICl）的影响。一种称为“Y管”的浓度跳跃技术被用于快速向外施用药剂。从1 - 3周龄大鼠中获得游离神经元。2. 当贴片移液液中含有2 mM‐ATP时，10（‐5）M‐GABA引起的ICl振幅在初始记录后超过60分钟内没有表现出任何时间依赖性的下降（明显的下降）。在ATP存在的情况下，根据GABA浓度响应曲线计算的半最大浓度（KD）和Hill系数分别为9.12微米和1.47微米。3. 在缺乏细胞内ATP的情况下，GABA诱导的ICl的振幅随时间下降。相对于初始反应，20和60分钟后的相对峰幅分别为0.40 +/‐0.09 （n = 11）和0.16 +/‐0.05 （n = 8）。4. 即使存在2mm的细胞内ATP，从内部溶液中去除Mg2+也会引起GABA反应的下降，这表明细胞内ATP （2mm或更多）和Mg2+对于防止GABA反应的下降是必要的。5. 碱性磷酸酶（100 - 200微米）激活去磷酸化过程不影响神经元内灌注含有2 mM‐ATP和3 mM‐Mg2+的溶液时的GABA反应。用冈田酸（一种磷酸酶抑制剂）阻断去磷酸化过程并不能阻止GABA反应的下降。6. 通过电压依赖性L型Ca2+通道和谷氨酸受体操作的阳离子通道的钙流入对GABA诱导的ICl没有影响。7. GABA诱导的ICl也可以通过向含有Mg2+的内溶液中加入2 mM‐ADP或ATP γ S（腺苷‐5′‐O‐3‐硫代三磷酸）来维持。在内部溶液中加入2mm‐腺苷、AMP、环AMP、AMP‐PNP（腺苷二磷酸）或ADP β S（腺苷‐5′‐O‐2‐硫代二磷酸），即使在存在3mm‐细胞内Mg2+的情况下，也不能阻止GABA反应的下降。基于这些ATP类似物的化学特异性，提示在细胞膜的细胞质侧存在ATP敏感结合位点（ATP受体）。（摘要删节为400字）
1. Effect of intracellular ATP on Cl‐ current (ICl) mediated by the GABA (gamma‐aminobutyric acid) receptor subtype, GABAA, was studied in dissociated nucleus tractus solitarii (NTS) neurones using the whole‐cell mode of patch clamp. A concentration‐jump technique termed ‘Y tube’ was used to rapidly apply agents externally. Dissociated neurones were obtained from 1‐ to 3‐week‐old rats. 2. When the patch‐pipette solution contained 2 mM‐ATP, the amplitude of ICl elicited by 10(‐5) M‐GABA did not show any time‐dependent decrease (apparent run‐down), for more than 60 min after the initial recording. In the presence of ATP, the half‐maximum concentration (KD) and Hill coefficient calculated from the GABA concentration‐response curve were 9.12 microM and 1.47, respectively. 3. In the absence of intracellular ATP, the amplitude of GABA‐induced ICl decreased with time. The relative peak amplitudes after 20 and 60 min from the initial recording were 0.40 +/‐ 0.09 (n = 11) and 0.16 +/‐ 0.05 (n = 8) with respect to the initial response. 4. Removal of Mg2+ from the internal solution induced run‐down of the GABA response even in the presence of 2 mM‐intracellular ATP, suggesting that both intracellular ATP (2 mM or more) and Mg2+ are necessary to prevent run‐down of the GABA response. 5. Activation of dephosphorylation processes by alkaline phosphatase (100‐200 microM) did not affect the GABA response in neurones perfused with internal solution containing 2 mM‐ATP and 3 mM‐Mg2+. Blocking the dephosphorylation process by okadaic acid, a phosphatase inhibitor, did not prevent the run‐down of the GABA response. 6. Calcium influxes passing through both the voltage‐dependent L‐type Ca2+ channel and the glutamate receptor‐operated cation channel did not affect ICl induced by GABA. 7. GABA‐induced ICl was also maintained by adding 2 mM‐ADP or ATP gamma S (adenosine‐5'‐O‐3‐thiotriphosphate) to the internal solution containing Mg2+. Addition of 2 mM‐adenosine, AMP, cyclic AMP, AMP‐PNP (adenylimido‐diphosphate) or ADP beta S (adenosine‐5'‐O‐2‐thiodiphosphate) to the internal solution did not prevent the run‐down of the GABA response even in the presence of 3 mM‐intracellular Mg2+. Based on the chemical specificity of these ATP analogues, it is suggested that there is an ATP‐sensitive binding site (ATP receptor) in the cytoplasmic side of the cell membrane.(ABSTRACT TRUNCATED AT 400 WORDS)
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影响因子：
3.6
作者：
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影响因子：
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作者：
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DOI：
10.1073/pnas.87.4.1315
发表时间：
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影响因子：
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作者：
Browning,MD;Bureau,M;Dudek,EM;Olsen,RW
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DOI：
10.1016/0165-1838(83)90129-7
发表时间：
1983
期刊：
Journal of the autonomic nervous system
影响因子：
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作者：
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通讯作者：
Sawchenko,PE