Evaluate the effects of chronic MDMA uptakes to cerebral metabolism using proton magnetic resonance spectroscopy (1H MRS)

• Main Authors: Wei-Yin Liu, 劉薇音
• Other Authors: Woei-Chyn Chu
• Format: Others
• Language: en_US
• Published: 2007
• Online Access: http://ndltd.ncl.edu.tw/handle/88178218623195597201

碩士 === 國立陽明大學 === 醫學工程研究所 === 95 === 3,4-Methylenedioxymethamphetamine, MDMA, is a widely abused amphetamine derivative that alters serotonin (5-HT) release via degrading the reverse serotonin re-uptake transporter (SERT) mechanism. This phenomenon leads to neurotoxicity in the synaptic cleft, especially in the striatum. The major function of the striatum is planning and modulating movement pathways and cognitive processes. The objective of this study is to investigate the immediate neuronal viability on chronic MDMA-influenced rats and the effect of re-challenged MDMA. This study measures cerebral metabolites of seven Sprague-Dawley male rats with non-invasively proton magnetic resonance spectroscopy (1H MRS) to evaluate if chronic MDMA injections could cause neurons in the striatum dysfunctions or loss. Because N-acetylaspartate (NAA) reflects neuronal dysfunctions or loss in a brain, and NAA divided by creatine (Cr) is commonly utilized because it remains unchanged in a variety of brain diseases. Previous proton MRS study examining NAA/Cr ratio have shown lowered NAA in midfrontal gray matter that correlated well with impaired delayed recall in MDMA users. The NAA to Cr ratio (NAA/Cr) was significantly decreased in the bilateral striatum following the first 7-day MDMA injection. It recovered to normal on the 21st day. By re-challenging the same dose MDMA injection on the 21st day, NAA/Cr was rapidly decreased to the lowest value compared to the first 7-day chronic MDMA injection and was significantly lower than that of Day 1. Afterwards, NAA/Cr again quickly returns to normal value. There is no significant change in T2 weighted images. In conclusion, the abnormal NAA concentration suggests a significant neuronal dysfunction in MDMA rats. The neuronal dysfunction, which might lead to cognitive and behavioural deficits, seems transient and reversible during one month time period. The effect of re-challenge to 10mg/kg MDMA after pretreatment MDMA produced more severe effects in terms of the absolute rate of NAA/Cr drops, thus it might be inferred that re-challenged MDMA users may be exposed to a higher life-threatening risk. In addition, proton MRS is a suitable tool for non-invasive and in vivo evaluation of the functional changes of the cerebral metabolism. Key words: MRS, MDMA, metabolism