Oleoyl-L-carnitine inhibits glycine transport by GlyT2
Oleoyl-L-carnitine inhibits glycine transport by GlyT2
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DOI：
10.1111/j.1476-5381.2012.02213.x
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发表时间：
2013-02-01
影响因子：
7.3
通讯作者：
Vandenberg, R. J.
中科院分区：
文献类型：
--
作者：
Carland, J. E.;Mansfield, R. E.;Vandenberg, R. J.
背景技术CNS中细胞外甘氨酸的浓度受两种Na+/Cl-依赖性甘氨酸转运蛋白GlyT 1和GlyT 2的调节。GlyT 1的选择性抑制剂已被开发用于治疗精神分裂症，而GlyT 2的选择性抑制剂在疼痛的动物模型中是镇痛剂。我们评估了一系列内源性脂质作为GlyT 1和GlyT 2的抑制剂。实验方法在非洲爪蟾卵母细胞中表达人GlyT 1和GlyT 2，并使用电生理技术测量了一系列酰基卡尼汀对甘氨酸转运的抑制作用。关键词L-左旋卡尼汀抑制GlyT 2的甘氨酸转运，IC 50为340 nM，其效力是先前鉴定的脂质抑制剂N-花生四烯酰-甘氨酸的15倍。油酰-L-肉毒碱具有缓慢的抑制作用和缓慢的洗脱。利用一系列嵌合型GlyT 1/2转运蛋白和点突变型转运蛋白，我们鉴定了GlyT 2胞外环4中的异亮氨酸残基，该残基赋予GlyT 2和GlyT 1对油酰-L-肉毒碱的敏感性差异。结论和意义油酰-L-肉毒碱是GlyT 2的有效非竞争性抑制剂。先前鉴定的GlyT 2抑制剂显示出作为镇痛剂的潜力，并且油酰-L-肉毒碱作为新型GlyT 2抑制剂的鉴定可能导致治疗疼痛的新方法。
BACKGROUND AND PURPOSEConcentrations of extracellular glycine in the CNS are regulated by two Na+/Cl--dependent glycine transporters, GlyT1 and GlyT2. Selective inhibitors of GlyT1 have been developed for the treatment of schizophrenia, whilst selective inhibitors of GlyT2 are analgesic in animal models of pain. We have assessed a series of endogenous lipids as inhibitors of GlyT1 and GlyT2.EXPERIMENTAL APPROACHHuman GlyT1 and GlyT2 were expressed in Xenopus laevis oocytes, and the inhibitory actions of a series of acylcarnitines on glycine transport were measured using electrophysiological techniques.KEY RESULTSOleoyl-L-carnitine inhibited glycine transport by GlyT2, with an IC50 of 340 nM, which is 15-fold more potent than the previously identified lipid inhibitor N-arachidonyl-glycine. Oleoyl-L-carnitine had a slow onset of inhibition and a slow washout. Using a series of chimeric GlyT1/2 transporters and point mutant transporters, we have identified an isoleucine residue in extracellular loop 4 of GlyT2 that conferred differences in sensitivity to oleoyl-L-carnitine between GlyT2 and GlyT1.CONCLUSIONS AND IMPLICATIONSOleoyl-L-carnitine is a potent non-competitive inhibitor of GlyT2. Previously identified GlyT2 inhibitors show potential as analgesics and the identification of oleoyl-L-carnitine as a novel GlyT2 inhibitor may lead to new ways of treating pain.