Amphetamine and Methamphetamine Differentially Affect Dopamine Transporters in Vitro and in Vivo
Amphetamine and Methamphetamine Differentially Affect Dopamine Transporters in Vitro and in Vivo
复制标题
DOI：
10.1074/jbc.m805298200
复制
发表时间：
2009-01-30
影响因子：
4.8
通讯作者：
Khoshbouei, Habibeh
中科院分区：
文献类型：
--
作者：
Goodwin, J. Shawn;Larson, Gaynor A.;Khoshbouei, Habibeh
精神兴奋剂D-苯丙胺（AMPH）和甲基苯丙胺（METH）将过量的多巴胺（DA）释放到多巴胺能神经元的突触裂隙中。异常DA释放被认为是通过DA转运蛋白（DAT）的反向转运发生的，并且被认为是这些药物严重行为效应的基础。在这里，我们比较了结构相似的AMPH和METH在异源表达系统和动物模型中对DAT功能的影响。在体外表达系统中，DAT介导的全细胞电流的METH刺激大于AMPH。在相同的电压和浓度下，METH释放的DA是AMPH的五倍，并且在生理膜电位下也是如此。在最大有效浓度下，与AMPH相比，METH从内部储存中释放的[Ca 2 +]（i）是AMPH的两倍。[Ca2（i）对两种药物的反应均不依赖于膜电压，但被DAT拮抗剂抑制。DAT N端结构域中的完整磷酸化位点是AMPH和METH诱导的[Ca 2 +]（i）增加和METH对[Ca 2 +]（i）升高的增强效应所必需的。钙调蛋白依赖性蛋白激酶II和蛋白激酶C抑制剂单独或组合也阻断AMPH或MET诱导的Ca 2+反应。最后，在大鼠延髓核，在体内伏安法表明，系统应用甲基抑制DAT介导的DA清除率比AMPH更有效，导致过量的外部DA。这些数据表明，甲基有一个更强的作用DAT介导的细胞生理比AMPH，这可能有助于欣快和成瘾的属性相比，与AMPH的甲基。
The psychostimulants D-amphetamine (AMPH) and methamphetamine (METH) release excess dopamine (DA) into the synaptic clefts of dopaminergic neurons. Abnormal DA release is thought to occur by reverse transport through the DA transporter (DAT), and it is believed to underlie the severe behavioral effects of these drugs. Here we compare structurally similar AMPH and METH on DAT function in a heterologous expression system and in an animal model. In the in vitro expression system, DAT-mediated whole-cell currents were greater for METH stimulation than for AMPH. At the same voltage and concentration, METH released five times more DA than AMPH and did so at physiological membrane potentials. At maximally effective concentrations, METH released twice as much [Ca2+](i) from internal stores compared with AMPH. [Ca2+](i) responses to both drugs were independent of membrane voltage but inhibited by DAT antagonists. Intact phosphorylation sites in the N-terminal domain of DAT were required for the AMPH-and METH-induced increase in [Ca2+](i) and for the enhanced effects of METH on [Ca2+](i) elevation. Calmodulin-dependent protein kinase II and protein kinase C inhibitors alone or in combination also blocked AMPH-or METH-induced Ca2+ responses. Finally, in the rat nucleus accumbens, in vivo voltammetry showed that systemic application of METH inhibited DAT-mediated DA clearance more efficiently than AMPH, resulting in excess external DA. Together these data demonstrate that METH has a stronger effect on DAT-mediated cell physiology than AMPH, which may contribute to the euphoric and addictive properties of METH compared with AMPH.