Accumulation and extrusion of permeant Ca2+ chelators in attenuation of synaptic transmission at hippocampal CA1 neurons
Accumulation and extrusion of permeant Ca2+ chelators in attenuation of synaptic transmission at hippocampal CA1 neurons
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渗透性 Ca2 螯合剂的积累和挤出导致海马 CA1 神经元突触传递减弱
DOI：
10.1016/0306-4522(96)00319-3
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发表时间：
1996
期刊：
影响因子：
3.3
通讯作者：
P. Carlen
中科院分区：
文献类型：
--
作者：
A. Ouanounou;L. Zhang;M. Tymianski;M. Charlton;M. Wallace;P. Carlen
在大鼠脑切片的海马 CA1 区域测定了细胞外应用的膜渗透性 Ca2+ 螯合剂对场兴奋性突触后电位的影响。用 0.05–50μM 双-(-O-氨基苯氧基)-乙烷-N,N,N,N,-四乙酸乙酰氧基甲基 (BAPTA-AM) 灌注 15 分钟，切片中的场兴奋性突触后电位以浓度依赖性方式可逆性衰减 10-45%。 BAPTA-AM 浓度较高时，衰减发生较早，因此表明 BAPTA 盐的积累速率是浓度依赖性的。逆向诱发反应和突触前齐射不受 BAPTA-AM 的影响。 BAPTA-AM 对场兴奋性突触后电位的衰减通过 1Hz 的重复刺激而暂时消除，表明螯合剂的 Ca2+ 结合能力饱和。场兴奋性突触后电位的幅度不受 5'5-二硝基-BAPTA-AM（一种低 Ca2+ 亲和力 BAPTA 类似物）和 EGTA-AM（5 或 50μM）（一种具有缓慢 Ca2+ 结合动力学的螯合剂）的类似应用的影响，表明 BAPTA-AM 效应依赖于快速 Ca2+ 结合和高 Ca2+ 亲和力。只要将施用时间延长至 40 分钟，BAPTA-AM 浓度低至 0.05μM 即可有效。丙磺舒 (1mM) 是一种阴离子转运抑制剂，可加速起效并显着增强低浓度 BAPTA-AM 引起的 BAPTA 介导的突触衰减。这些数据表明，只要突触前积累了足够的螯合剂，即使 BAPTA-AM 的细胞外浓度非常低，也能深刻影响突触传递。通过抑制螯合剂挤出的程序可以提高 BAPTA-AM 的有效性。
The effects of extracellularly applied membrane-permeant Ca2+chelators on field excitatory postsynaptic potentials were determined in the hippocampal CA1 region of rat brain slices. Field excitatory postsynaptic potentials in slices perfused with 0.05–50μM bis-(-O-aminophenoxy)-ethane-N,N,N,N,-tetraacetic acid acetoxymethyl (BAPTA-AM) for 15min were reversibly attenuated by 10–45% in a concentration-dependent manner. Attenuation occurred earlier at higher concentrations of BAPTA-AM, thus indicating that the rate of accumulation of BAPTA salt was concentration dependent. Antidromically evoked responses and presynaptic volleys were unaffected by BAPTA-AM. Attenuation of the field excitatory postsynaptic potentials by BAPTA-AM was temporarily eliminated by repetitive stimulation at 1Hz, suggesting saturation of the chelator's Ca2+-binding capacity. The amplitude of field excitatory postsynaptic potentials was unaffected by similar applications of 5′5-dinitro-BAPTA-AM, a low Ca2+-affinity BAPTA analogue, and EGTA-AM (5 or 50μM), a chelator with slow Ca2+-binding kinetics, suggesting a dependence of the BAPTA-AM effect on fast Ca2+binding and high Ca2+affinity. BAPTA-AM concentrations as low as 0.05μM were effective provided application was prolonged to 40min. Probenecid (1mM), an anion transport inhibitor, accelerated the onset and significantly enhanced the BAPTA-mediated synaptic attenuation caused by low concentrations of BAPTA-AM. These data show that even very low extracellular concentrations of BAPTA-AM can profoundly affect synaptic transmission provided that sufficient chelator accumulates presynaptically. The effectiveness of BAPTA-AM can be increased by procedures which inhibit chelator extrusion.
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通过氟 19 核磁共振波谱测定体内细胞内钙。
DOI：
10.1152/ajpcell.1995.269.2.c318
发表时间：
1995
期刊：
The American journal of physiology.
影响因子：
--
作者：
Song,SK;Hotchkiss,RS;Neil,J;MorrisJr,PE;Hsu,CY;Ackerman,JJ
通讯作者：
Ackerman,JJ
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DOI：
10.1152/jn.1995.73.1.178
发表时间：
1995
期刊：
Journal of neurophysiology.
影响因子：
--
作者：
Blundon,JA;Wright,SN;Brodwick,MS;Bittner,GD
通讯作者：
Bittner,GD
影响因子：
5.5
作者：
CHARLTON, MP;SMITH, SJ;ZUCKER, RS
通讯作者：
ZUCKER, RS
脑毛细血管内皮和脉络丛的丙磺舒敏感阴离子转运过程对丙戊酸从中枢神经系统有效流出的贡献。
DOI：
--
发表时间：
1994
期刊：
The Journal of pharmacology and experimental therapeutics
影响因子：
--
作者：
Adkison,KD;Artru,AA;Powers,KM;Shen,DD
通讯作者：
Shen,DD
细胞悬浮液中细胞质钙浓度的测量：通过使用 Mn2 和丙磺舒校正细胞外 Fura-2。
影响因子：
4
作者：
McDonough,PM;Button,DC
通讯作者：
Button,DC