Wu X, Gu H H
Yale University, School Of Medicine, Department Of Pharmacology, New Haven, CT 06510, USA.
Gene. 1999 Jun 11;233(1-2):163-70. doi: 10.1016/s0378-1119(99)00143-2.
Drug abuse is a serious problem in the United States and in the world. Cocaine and amphetamines, widely used drugs of abuse, bind to dopamine (DA), serotonin, and norepinephrine transporters with high affinity and block their functions. It is believed that the dopamine transporter plays a key role in the mechanism of cocaine addiction. Because a good portion of our knowledge about drug addiction is derived from studying mouse as an animal model, it is essential to compare the properties of dopamine transporter from human and mouse. We report here the cloning of the mouse dopamine transporter (mDAT) cDNA and its expression and comparison with the human DAT. The 3.4 kilobase (kb) cDNA encodes a polypeptide that is 93.5% identical to the hDAT, with 619 amino acid residues and a calculated molecular weight of 68.8kDa. Dopamine transporters from mouse and human were stably expressed in the same parental MDCK cells and their properties were compared. The Michaelis-Menten constant Km values are 2.0 microM for mDAT and 2.4 microM for hDAT. Mouse and human DAT were also compared for drug inhibition profiles. Dopamine transporters from the two species have the same sensitivity to amphetamine (Kd: 0.75 microM) and bupropion (Kd: 1.5 microM). However, hDAT is more sensitive than mDAT to cocaine (Kd: 0.14 microM and 0. 29 microM respectively) and to ritalin (Kd: 0.038 microM and 0. 12 microM respectively). The cloning of mDAT cDNA provides an important tool for further study of the mechanism of drug addiction using mouse as an animal model.
药物滥用在美国乃至全世界都是一个严重的问题。可卡因和苯丙胺是广泛滥用的药物，它们以高亲和力与多巴胺（DA）、5-羟色胺和去甲肾上腺素转运体结合并阻断其功能。人们认为多巴胺转运体在可卡因成瘾机制中起关键作用。由于我们关于药物成瘾的很多知识都来源于以小鼠作为动物模型的研究，因此比较人和小鼠多巴胺转运体的特性至关重要。我们在此报告小鼠多巴胺转运体（mDAT）cDNA的克隆、其表达情况以及与人类多巴胺转运体（hDAT）的比较。这个3.4千碱基（kb）的cDNA编码一个与hDAT有93.5%同一性的多肽，有619个氨基酸残基，计算分子量为68.8千道尔顿。小鼠和人类的多巴胺转运体在同一亲本MDCK细胞中稳定表达，并比较了它们的特性。米氏常数Km值，mDAT为2.0微摩尔，hDAT为2.4微摩尔。还比较了小鼠和人类DAT的药物抑制谱。这两个物种的多巴胺转运体对苯丙胺（解离常数Kd：0.75微摩尔）和安非他酮（Kd：1.5微摩尔）的敏感性相同。然而，hDAT对可卡因（Kd分别为0.14微摩尔和0.29微摩尔）和利他林（Kd分别为0.038微摩尔和0.12微摩尔）比mDAT更敏感。mDAT cDNA的克隆为以小鼠作为动物模型进一步研究药物成瘾机制提供了一个重要工具。
