Interactions between CB1 receptors and TRPV1 channels mediated by 12-HPETE are cytotoxic to mesencephalic dopaminergic neurons
Interactions between CB1 receptors and TRPV1 channels mediated by 12-HPETE are cytotoxic to mesencephalic dopaminergic neurons
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DOI：
10.1038/bjp.2008.246
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发表时间：
2008-09-01
影响因子：
7.3
通讯作者：
Jin, B. K.
中科院分区：
文献类型：
--
作者：
Kim, S. R.;Bok, E.;Jin, B. K.
背景和目的：我们最近提出了大麻素1型（CB 1）受体和瞬时受体电位香草素1（TRPV 1）通道在大鼠中脑文化之间的神经毒性相互作用的存在。本研究旨在为CB 1受体和TRPV 1之间的神经毒性相互作用的介质和机制寻找证据。实验方法：通过细胞活力测定、免疫细胞化学、Fura-2钙成像、线粒体形态学测定，ELISA和Western印迹法在体外富集神经元的中脑培养物。关键结果：神经毒性相互作用是由内源性TRPV 1激动剂12（S）-HPETE介导的。CB 1受体激动剂（HU 210和WIN 55，212-2）增加12（S）-羟基二十碳四烯酸（12（S）-HETE）的水平，12（S）-HPETE的下游代谢物，其在体外和体内刺激TRPV 1介导的中脑神经元死亡。神经毒性是由细胞内Ca ~（2+）浓度升高介导的（[Ca 2 +]（i））通过TRPV 1，从而导致线粒体损伤，并减弱黄芩素，12-脂氧合酶抑制剂。大鼠中脑神经元中CB 1受体的激活与12（S）-HPETE的生物合成相关，12（S）-HPETE反过来刺激TRPV 1活性，导致[Ca 2 +]（i）增加，线粒体损伤和神经元死亡。
Background and purposes: We recently proposed the existence of neurotoxic interactions between the cannabinoid type 1 (CB1) receptor and transient receptor potential vanilloid 1 (TRPV1) channels in rat mesencephalic cultures. This study seeks evidence for the mediator(s) and mechanisms underlying the neurotoxic interactions between CB1 receptors and TRPV1 in vitro and in vivo.Experimental approach: The mediator( s) and mechanism( s) for the interactions between CB1 receptors and TRPV1 were evaluated by cell viability assays, immunocytochemistry, Fura-2 calcium imaging, mitochondrial morphology assay, ELISA and Western blot assay in vitro in neuron-enriched mesencephalic cultures. Injections into the substantia nigra and subsequent cell counts were also used to confirm these interactions in vivo.Key results: The neurotoxic interactions were mediated by 12(S)-hydroperoxyeicosatetraenoic acid (12(S)-HPETE), an endogenous TRPV1 agonist. CB1 receptor agonists (HU210 and WIN55,212-2) increased the level of 12(S)-hydroxyeicosatetraenoic acid (12(S)-HETE), a downstream metabolite of 12(S)-HPETE, which stimulates TRPV1-mediated death of mesencephalic neurons, both in vitro and in vivo. The neurotoxicity was mediated by increased intracellular Ca2+ concentration ([Ca2+](i)) through TRPV1, consequently leading to mitochondrial damage and was attenuated by baicalein, a 12-lipoxygenase inhibitor.Conclusion and implications: Activation of CB1 receptors in rat mesencephalic neurons was associated with biosynthesis of 12(S)-HPETE, which in turn stimulated TRPV1 activity, leading to increased [Ca2+](i), mitochondrial damage and neuronal death.