Inhibition of plasmalemmal Na+/Ca2+ exchange by mitochondrial Na+/Ca2+ exchange inhibitor 7-chloro-5-(2-chlorophenyl)-1,5-dihydro-4,1-benzothiazepin-2(3H)-one (CGP-37157) in cerebellar granule cells
Inhibition of plasmalemmal Na+/Ca2+ exchange by mitochondrial Na+/Ca2+ exchange inhibitor 7-chloro-5-(2-chlorophenyl)-1,5-dihydro-4,1-benzothiazepin-2(3H)-one (CGP-37157) in cerebellar granule cells
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DOI：
10.1016/j.bcp.2003.08.024
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发表时间：
2003-12-15
影响因子：
5.8
通讯作者：
Kiedrowski, L
中科院分区：
文献类型：
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作者：
Czyz, A;Kiedrowski, L
在心脏中，7-氯-5-（2-氯苯基）-1，5-二氢-4，1-苯并硫氮杂卓-2（3 H）-酮（CGP-37157）抑制线粒体但不抑制肌膜Na+/Ca 2+交换。因此，CGP-37157经常被用作研究线粒体Na+/Ca 2+交换在各种细胞（包括神经元）中Ca 2+稳态中的作用的实验工具。然而，神经元表达质膜Na+/Ca 2+交换的几种K+依赖性（NCKX）和/或K+非依赖性（NCX）亚型，而肌膜中不表达。因为从未确定CGP-37157是否抑制神经元中的质膜NCKX和/或NCX亚型，所以我们测试了这种可能性。作为NCKX和/或NCX活性的指标，我们分别研究了在存在和不存在K+的情况下Na依赖性和短杆菌肽诱导的Ca-45（2+）积累。在原代培养的小脑颗粒细胞中，CGP-37157的IC_（50）为13 μ M，可抑制70%以上的质膜NCX活性（P < 0.01），但不抑制NCKX活性。我们的数据表明，CGP-37157对神经元Ca 2+稳态的影响包括抑制某些质膜NCX亚型。由于小脑颗粒细胞强烈表达NCX 3转录本，而在心脏中不表达，因此似乎这种同种型可能对CGP-37157敏感。(C)2003年爱思唯尔公司All rights reserved.
In the heart, 7-chloro-5-(2-chlorophenyl)-1,5-dihydro-4, 1-benzothiazepin-2(3H)-one (CGP-37157) inhibits mitochondrial but not sarcolemmal Na+/Ca2+ exchange. Therefore, CGP-37157 is often used as an experimental tool to study the role of mitochondrial Na+/Ca2+ exchange in Ca2+ homeostasis in various cells, including neurons. However, neurons express several K+-dependent (NCKX) and/or K+-independent (NCX) isoforms of plasmalemmal Na+/Ca2+ exchange not expressed in the sarcolemma. Because it has never been determined whether CGP-37157 inhibits plasmalemmal NCKX and/or NCX isoforms in neurons, we tested this possibility. As an index of NCKX and/or NCX activity, we studied Na-dependent and gramicidin-induced Ca-45(2+) accumulation in the presence and absence of K+, respectively. In primary cultures of cerebellar granule cells, CGP-37157 with IC50 of 13 muM inhibited over 70% of plasmalemmal NCX activity (P < 0.01) but not NCKX activity. Our data suggest that the effects of CGP-37157 on neuronal Ca2+ homeostasis include inhibition of certain plasmalemmal NCX isoform(s). Because cerebellar granule cells robustly express NCX3 transcripts, which are not expressed in the heart, it appears that this isoform may be CGP-37157 sensitive. (C) 2003 Elsevier Inc. All rights reserved.