背根神经节杂交神经元中GABA(A)和GABA(B)受体介导的对细胞内Ca(2+)影响的分析

Analysis of GABA(A)- and GABA(B)-receptor mediated effects on intracellular Ca(2+) in DRG hybrid neurones.

作者信息

Yokogawa T, Kim S U, Krieger C, Puil E

机构信息

Division of Neurology, Department of Medicine, The University of British Columbia, Vancouver, BC, Canada.

出版信息

Br J Pharmacol. 2001 Sep;134(1):98-107. doi: 10.1038/sj.bjp.0704244.

DOI:10.1038/sj.bjp.0704244

PMID:11522601

原文链接:https://pmc.ncbi.nlm.nih.gov/articles/PMC1572933/

Abstract

Using pharmacological analysis and fura-2 spectrofluorimetry, we examined the effects of gamma-aminobutyric acid (GABA) and related substances on intracellular Ca(2+) concentration ([Ca(2+)]i) of hybrid neurones, called MD3 cells. The cell line was produced by fusion between a mouse neuroblastoma cell and a mouse dorsal root ganglion (DRG) neurone. 2. MD3 cells exhibited DRG neurone-like properties, such as immunoreactivity to microtubule-associated protein-2 and neurofilament proteins. Bath applications of capsaicin and alpha, beta-methylene adenosine triphosphate reversibly increased [Ca(2+)]i. However, repeated applications of capsaicin were much less effective. 3. Pressure applications of GABA (100 microM), (Z)-3-[(aminoiminomethyl) thio] prop-2-enoic acid sulphate (ZAPA; 100 microM), an agonist at low affinity GABA(A)-receptors, or KCl (25 mM), transiently increased [Ca(2+)]i. 4. Bath application of bicuculline (100 nM - 100 microM), but not picrotoxinin (10 - 25 microM), antagonized GABA-induced increases in [Ca(2+)]i in a concentration-dependent manner (IC(50)=9.3 microM). 5. Ca(2+)-free perfusion reversibly abolished GABA-evoked increases in [Ca(2+)]i. Nifedipine and nimodipine eliminated GABA-evoked increases in [Ca(2+)]i. These results imply GABA response dependence on extracellular Ca(2+). 6. Baclofen (500 nM - 100 microM) activation of GABA(B)-receptors reversibly attenuated KCl-induced increases in [Ca(2+)]i in a concentration-dependent manner (EC(50)=1.8 microM). 2-hydroxy-saclofen (1 - 20 microM) antagonized the baclofen-depression of the KCl-induced increase in [Ca(2+)]i. 7. In conclusion, GABA(A)-receptor activation had effects similar to depolarization by high external K(+), initiating Ca(2+) influx through high voltage-activated channels, thereby transiently elevating [Ca(2+)]i. GABA(B)-receptor activation reduced Ca(2+) influx evoked by depolarization, possibly at Ca(2+)-channel sites in MD3 cells.

摘要

我们运用药理学分析和fura - 2荧光分光光度法，研究了γ-氨基丁酸（GABA）及相关物质对一种名为MD3细胞的杂交神经元细胞内钙离子浓度（[Ca(2+)]i）的影响。该细胞系由小鼠神经母细胞瘤细胞与小鼠背根神经节（DRG）神经元融合产生。2. MD3细胞表现出类似DRG神经元的特性，如对微管相关蛋白-2和神经丝蛋白具有免疫反应性。辣椒素和α,β-亚甲基三磷酸腺苷的浴槽给药可使[Ca(2+)]i可逆性升高。然而，重复给予辣椒素的效果则要差得多。3. 对GABA（100微摩尔）、低亲和力GABA(A)受体激动剂(Z)-3-[(氨基亚氨甲基)硫代]丙烯酸硫酸盐（ZAPA；100微摩尔）或氯化钾（25毫摩尔）进行压力给药，可使[Ca(2+)]i短暂升高。4. 浴槽给予荷包牡丹碱（100纳摩尔 - 100微摩尔），而非苦味毒（10 - 25微摩尔），可浓度依赖性地拮抗GABA诱导的[Ca(2+)]i升高（IC(50)=9.3微摩尔）。5. 无钙灌注可使GABA诱发的[Ca(2+)]i升高可逆性消除。硝苯地平和尼莫地平可消除GABA诱发的[Ca(2+)]i升高。这些结果表明GABA反应依赖于细胞外钙离子。6. 巴氯芬（500纳摩尔 - 100微摩尔）激活GABA(B)受体可浓度依赖性地可逆性减弱氯化钾诱导的[Ca(2+)]i升高（EC(50)=1.8微摩尔）。2-羟基-巴氯芬（1 - 20微摩尔）可拮抗巴氯芬对氯化钾诱导的[Ca(2+)]i升高的抑制作用。7. 总之，GABA(A)受体激活具有与高细胞外钾离子去极化类似的作用，通过高电压激活通道引发钙离子内流，从而短暂升高[Ca(2+)]i。GABA(B)受体激活可减少去极化诱发的钙离子内流，可能作用于MD3细胞的钙离子通道部位。