Department of Physiology, College of Medicine, The Catholic University of Korea, 222 Banpo-daero Seocho-gu, Seoul 06591, South Korea.
Department of Physiology, College of Medicine, The Catholic University of Korea, 222 Banpo-daero Seocho-gu, Seoul 06591, South Korea; Catholic Neuroscience Institute, The Catholic University of Korea, 222 Banpo-daero Seocho-gu, Seoul 06591, South Korea.
Eur J Pharmacol. 2017 Jun 15;805:36-45. doi: 10.1016/j.ejphar.2017.03.033. Epub 2017 Mar 16.
Selective serotonin reuptake inhibitors (SSRIs) have an inhibitory effect on various ion channels including Ca channels. We used fluorescent dye-based digital imaging, whole-cell patch clamping and cytotoxicity assays to examine whether dapoxetine, a novel rapid-acting SSRI, affect glutamate-induced calcium signaling, mitochondrial depolarization and neuronal cell death in cultured rat hippocampal neurons. Pretreatment with dapoxetine for 10min inhibited glutamate-induced intracellular free Ca concentration ([Ca]) increases in a concentration-dependent manner (Half maximal inhibitory concentration=4.79µM). Dapoxetine (5μM) markedly inhibited glutamate-induced [Ca] increases, whereas other SSRIs such as fluoxetine and citalopram only slightly inhibited them. Dapoxetine significantly inhibited the glutamate-induced [Ca] responses following depletion of intracellular Ca stores by treatment with thapsigargin. Dapoxetine markedly inhibited the metabotropic glutamate receptor agonist, (S)-3,5-dihydroxyphenylglycine-induced [Ca] increases. Dapoxetine significantly inhibited the glutamate and α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA)-induced [Ca] responses in either the presence or absence of nimodipine. Dapoxetine also significantly inhibited AMPA-evoked currents. However, dapoxetine slightly inhibited N-methyl-D-aspartate (NMDA)-induced [Ca] increases. Dapoxetine markedly inhibited 50mMK-induced [Ca] increases. Dapoxetine significantly inhibited glutamate-induced mitochondrial depolarization. In addition, dapoxetine significantly inhibited glutamate-induced neuronal cell death and its neuroprotective effect was significantly greater than fluoxetine. These data suggest that dapoxetine reduces glutamate-induced [Ca] increases by inhibiting multiple pathways mainly through AMPA receptors, voltage-gated L-type Ca channels and metabotropic glutamate receptors, which are involved in neuroprotection against glutamate-induced cell death through mitochondrial depolarization.
选择性 5-羟色胺再摄取抑制剂（SSRIs）对包括钙通道在内的各种离子通道具有抑制作用。我们使用荧光染料基数字成像、全细胞膜片钳和细胞毒性测定法来研究达泊西汀（一种新型快速作用的 SSRI）是否会影响培养的大鼠海马神经元中的谷氨酸诱导的钙信号转导、线粒体去极化和神经元细胞死亡。达泊西汀预处理 10min 以浓度依赖性方式抑制谷氨酸诱导的细胞内游离 Ca 浓度 ([Ca]) 增加（半抑制浓度=4.79µM）。达泊西汀（5μM）显著抑制谷氨酸诱导的 [Ca] 增加，而其他 SSRIs（如氟西汀和西酞普兰）则仅轻微抑制。达泊西汀可显著抑制经 thapsigargin 处理耗尽细胞内 Ca 储存后谷氨酸诱导的 [Ca] 反应。达泊西汀显著抑制代谢型谷氨酸受体激动剂（S）-3,5-二羟基苯甘氨酸诱导的 [Ca] 增加。达泊西汀在有或没有尼莫地平的情况下均显著抑制谷氨酸和 α-氨基-3-羟基-5-甲基-4-异恶唑丙酸（AMPA）诱导的 [Ca] 反应。达泊西汀还显著抑制 AMPA 诱发的电流。然而，达泊西汀轻微抑制 N-甲基-D-天冬氨酸（NMDA）诱导的 [Ca] 增加。达泊西汀显著抑制 50mM K+诱导的 [Ca] 增加。达泊西汀显著抑制谷氨酸诱导的线粒体去极化。此外，达泊西汀显著抑制谷氨酸诱导的神经元细胞死亡，其神经保护作用明显大于氟西汀。这些数据表明，达泊西汀通过抑制包括 AMPA 受体、电压门控 L 型钙通道和代谢型谷氨酸受体在内的多种途径来减少谷氨酸诱导的 [Ca] 增加，这与通过线粒体去极化对抗谷氨酸诱导的细胞死亡有关。
