Heekeren Karsten, Daumann Jörg, Geyer Mark A, Gouzoulis-Mayfrank Euphrosyne
Department of Psychiatry and Psychotherapy, University of Technology (RWTH), Pauwelsstrasse 30, 52074 Aachen, Germany.
Psychopharmacology (Berl). 2004 May;173(3-4):418-24. doi: 10.1007/s00213-003-1729-y. Epub 2004 Jan 14.
3,4-Methylenedioxymethamphetamine (MDMA, ecstasy) is neurotoxic upon central serotonin systems in experimental animals and probably also in humans. Serotonin is involved in the habituation, sensitization and prepulse inhibition (PPI) of the startle reflex.
To study the plasticity of startle reflex in currently abstinent MDMA users.
Electromyographic responses to acoustic startle stimuli (pulse alone and prepulse-pulse trials) were recorded in 23 currently abstinent ecstasy users and 20 matched control subjects. Depending on the extent of their previous drug use ecstasy users were divided into two groups [life-time dose <90 (n=11) and > or =90 pills (n=12), respectively].
There were no significant differences in habituation, sensitization or PPI of the startle reflex between the entire group of ecstasy users and controls. However, sensitization of the startle reflex was stronger in the > or =90 compared with either the <90 MDMA pills or the control group. Correlations between patterns of drug use and startle parameters did not reach the level of significance, although users with a younger age at the onset of MDMA (and other drug) use tended to present with higher sensitization of the startle reflex.
Heavy users of MDMA (and other recreational drugs) present with strong sensitization of the startle reflex. Nevertheless, it is unclear whether this finding is secondary to the use of MDMA and its well-recognized neurotoxic potential. Alternatively, strong sensitization might reflect a pre-existing trait predisposing to drug use. A clearer picture of the impact of ecstasy on startle plasticity may be obtained from longitudinal investigations.
3,4-亚甲基二氧甲基苯丙胺（摇头丸）对实验动物的中枢5-羟色胺系统具有神经毒性，对人类可能也有同样作用。5-羟色胺与惊吓反射的习惯化、敏感化及前脉冲抑制（PPI）有关。
研究目前已戒毒的摇头丸使用者惊吓反射的可塑性。
记录了23名目前已戒毒的摇头丸使用者和20名匹配的对照者对听觉惊吓刺激（单独脉冲及前脉冲-脉冲试验）的肌电图反应。根据先前使用药物的程度，摇头丸使用者被分为两组[终生使用剂量<90片（n = 11）和≥90片（n = 12）]。
摇头丸使用者和对照者在惊吓反射的习惯化、敏感化或PPI方面无显著差异。然而，与<90片摇头丸组或对照组相比，≥90片组的惊吓反射敏感化更强。尽管开始使用摇头丸（及其他药物）时年龄较小的使用者往往表现出更强的惊吓反射敏感化，但药物使用模式与惊吓参数之间的相关性未达到显著水平。
大量使用摇头丸（及其他娱乐性药物）者表现出强烈的惊吓反射敏感化。然而，尚不清楚这一发现是否继发于摇头丸的使用及其公认的神经毒性潜能。或者，强烈的敏感化可能反映了一种预先存在的、易导致药物使用的特质。通过纵向研究可能会更清楚地了解摇头丸对惊吓可塑性的影响。
