Role of multidrug resistance protein 1a (MDR1a) in methamphetamine and methylened

甲基苯丙胺是一种精神兴奋剂，可导致大脑中神经递质多巴胺和多巴胺转运蛋白的长期耗竭。多巴胺和多巴胺转运蛋白的减少可能导致精神运动减慢和记忆障碍。​虽然MDMA在结构上与冰毒相似，但MDMA的效果不同。MDMA影响多种神经递质通路，包括血清素、多巴胺和去甲肾上腺素。研究表明，大量使用MDMA的人类受试者存在长期的记忆和学习障碍。多药耐药蛋白1a （MDR1a）是一种位于血脑屏障（BBB）中的蛋白质，它可以将大脑中的特定有毒物质运输回血脑屏障，从而保护脑细胞免受损伤。我们假设MDR1a转运甲基苯丙胺和MDMA在药物神经毒性中起作用。该项目使用mdr1a敲除小鼠和野生型小鼠来确定1)mdr1a运输甲基苯丙胺和MDMA是否会导致甲基苯丙胺或MDMA脑浓度的改变，以及2)这些脑浓度的改变是否与甲基苯丙胺或MDMA给药后的神经毒性相关。气相色谱-质谱法将用于测量mdr1a敲除小鼠和野生型小鼠在给予冰毒或MDMA后脑和血浆中的冰毒、MDMA及其代谢物的浓度。采用高效液相色谱法测定mdr1a基因敲除小鼠和野生型小鼠给药后脑内神经递质浓度。此外，脑内神经递质转运蛋白水平也将通过免疫印迹法测定。

Methamphetamine (METH) is a psychostimulant causing prolonged depletion of the neurotransmitter dopamine and dopamine transporter protein in brain. Decreases in dopamine and dopamine transporter protein may cause psychomotor slowing and memory impairments. Methylenedioxymethamphetamine (MDMA, ecstasy) is an amphetamine-derived drug that possesses stimulant and hallucinogenic properties. Although, MDMA is structurally similar to METH, MDMAs effects differ. MDMA affects multiple neurotransmitter pathways, including serotonin, dopamine and norepinephrine. Studies have demonstrated long-term impairments of memory and learning in human subjects reporting heavy MDMA use. Multidrug resistance protein 1a (MDR1a) is a protein located in the blood-brain barrier (BBB) that can transport specific toxic substances in the brain back across the BBB, thereby protecting brain cells from damage. We hypothesize that MDR1a transport of METH and MDMA plays a role in the drugs neurotoxicity. This project uses mdr1a knock-out and wild-type mice to determine 1) whether transport of METH and MDMA by MDR1a results in altered brain concentrations of METH or MDMA and 2) whether these altered brain concentrations correlate with neurotoxicity following METH or MDMA administration. Gas chromatography-mass spectrometry will be used to measure concentrations of METH, MDMA and metabolites in brain and plasma of mdr1a knock-out and wild-type mice following administration of METH or MDMA. High-performance liquid chromatography will be used to measure neurotransmitter concentrations in brains of mdr1a knock-out and wild-type mice after administration of METH or MDMA. Furthermore, levels of neurotransmitter transport proteins in brain also will be measured via Western blotting.