Clemens Kelly J, Cornish Jennifer L, Hunt Glenn E, McGregor Iain S
School of Psychology A16, University of Sydney, NSW 2006, Australia.
Pharmacol Biochem Behav. 2006 Oct;85(2):454-63. doi: 10.1016/j.pbb.2006.09.015. Epub 2006 Nov 15.
The combined use of 3,4-methylenedioxymethamphetamine (MDMA, 'Ecstasy') with methamphetamine (METH) by recreational drug users is of particular concern due to their similar pharmacological and toxic profiles. In the current study we sought to elucidate why combining these particular drugs is such a popular choice among party-drug users. This was investigated through characterisation of the possible interactive effects of MDMA on METH intravenous self-administration. The first experiment involved characterisation of the METH dose-response curve for intravenous self-administration. Male Hooded-Wistar rats were trained to self-administer intravenous METH (0.01-0.3 mg/kg/infusion) and an inverted-U dose-response curve was obtained. In Experiment 2, a second squad of rats self-administered 0.01, 0.03 or 0.1 mg/kg/infusion METH and had small amounts of MDMA (0.001-0.03 mg/kg) then introduced into the infusion solution. Addition of MDMA to the METH infusion solution resulted in a dose independent reduction in responding. In Experiment 3, a third squad of rats was treated 20 min pre-session with an intraperitoneal injection of saline, 1.25 or 2.5 mg/kg of MDMA or METH to evaluate whether the reduction in responding evident in Experiment 2 was due to an MDMA-induced decrease in locomotor activity. Pre-treatment with intraperitoneal MDMA or METH had no effect on METH self-administration nor activity. We hypothesise that the reduction in METH self-administration caused by MDMA may reflect inhibitory effects of MDMA-induced 5-HT release on dopaminergic mechanisms.
娱乐性药物使用者将3,4-亚甲基二氧甲基苯丙胺（摇头丸，MDMA）与甲基苯丙胺（冰毒，METH）混合使用，因其具有相似的药理和毒性特征而备受关注。在本研究中，我们试图阐明为何将这两种特定药物混合使用在派对药物使用者中如此受欢迎。我们通过表征MDMA对METH静脉自我给药可能的交互作用来对此进行研究。第一个实验涉及表征METH静脉自我给药的剂量反应曲线。对雄性帽状-威斯塔大鼠进行训练，使其静脉自我给药METH（0.01 - 0.3毫克/千克/输注），并获得了一条倒U形剂量反应曲线。在实验2中，另一组大鼠自我给药0.01、0.03或0.1毫克/千克/输注的METH，并在输注溶液中加入少量MDMA（0.001 - 0.03毫克/千克）。向METH输注溶液中添加MDMA导致反应呈剂量无关性降低。在实验3中，第三组大鼠在实验开始前20分钟接受腹腔注射生理盐水、1.25或2.5毫克/千克的MDMA或METH，以评估实验2中明显的反应降低是否是由于MDMA诱导的运动活动减少所致。腹腔注射MDMA或METH预处理对METH自我给药和活动均无影响。我们假设，MDMA导致的METH自我给药减少可能反映了MDMA诱导的5-羟色胺释放对多巴胺能机制的抑制作用。
