Comparison Of Striatal Dopamine Transporter Levels In Chronic Heroin Dependent Subjects And Methamphetamine Dependent Subjects

Section1Dopamine transporter levels in detoxified heroin dependent subjects:A99mTc-TRODAT-1SPECT imaging study[Objective] To explore the effect of heroin addiction on dopamine transporter (DAT), we assessed the DAT levels in the striatum by99mTc-TRODAT-l SPECT brain imaging in heroin abusers.[Methods] We recruited healthy human controls (n=21), and heroin dependent subjects (n=23). The heroin dependent subjects exhibited negative urine toxicology after undergoing physiological detoxification for two weeks. All subjects underwent SPECT brain imaging after two weeks abstinence. SPECT scans performed at2-3hours after the intravenous injection of99mTc-TRODAT-1. Specific tracer uptake was assessed bilaterally in the regions of interest (ROIs), namely, the striatum, the caudate nucleus, and the putamen.[Results] A significant specific uptake ratios (SURs) reduction in heroin dependent subjects compared with healthy controls was found in left striatum (1.33±0.17vs1.97±0.41; t=6.63,P<0.001), right striatum (1.28±0.19vs1.99±0.39; t=7.55, P<0.001), left caudate nucleus (1.32±0.16vs2.01±0.42; t=7.13, P<0.001), right caudate nucleus (1.27±0.19vs2.05±0.41; t=7.87, P<0.001), left putamen (1.33±0.18vs1.91±0.40; t=6.10, P<0.001), and right putamen (1.28±0.19vs1.93±0.38; t=7.14, P<0.001). There was no significant correlation with the DAT levels in heroin abusers and craving scores (1.70±1.66), HAMA (15.39±7.50) and HAMD (13.17±6.63).[Conclusions] This study results indicated that abstinent heroin dependent subjects had a lower DAT levels in the striatum than health controls. These findings suggest that chronic heroin abuse may impair the striatal dopamine neuron. Section2Reduced striatal dopamine transporter levels in chronic methamphetamine dependent subjects:A99mTc-TRODAT-1SPECT imaging study[Objective] To study the effect of methamphetamine (METH) addiction on DAT, we assessed the DAT levels in the striatum by99mTc-TRODAT-1single photon emission computed tomography (SPECT) brain imaging in healthy volunteers and METH dependent subjects.[Methods] We recruited healthy human controls (n=21) and METH abusers (n=25). The METH dependent subjects exhibited negative urine toxicology after undergoing physiological detoxification for two weeks. All subjects underwent SPECT brain imaging after two weeks abstinence. SPECT scans performed at2-3hours after the intravenous injection of99mTc-TRODAT-1. Specific tracer uptake was assessed bilaterally in the ROIs, namely, the striatum, the caudate nucleus, and the putamen.[Results] A significant SURs reduction in heroin dependent subjects and METH dependent subjects compared with healthy controls was found in left striatum (1.24±0.31vs1.97±0.41, t=6.80, P<0.001), right striatum (1.23±0.33vs1.99±0.39, t=7.02, P<0.001), left caudate nucleus (1.26±0.33vs2.01±0.42, t=6.84, P<0.001), right caudate nucleus (1.25±0.35vs2.05±0.41, t=7.10, P<0.001), left putamen (1.22±0.31vs1.91±0.40, t=6.62, P<0.001), and right putamen (1.22±0.32vs1.93±0.38, t=6.94, P<0.001). Craving were negatively correlated with DAT levels in the right striatum, the right caudate nucleus and the right putamen of METH dependent subjects(r=-0.04; r=-0.39; r=-0.41)[Conclusions] Our results indicated that people with METH dependence who are currently abstinent had lower DAT levels in striatum than healthy controls. Craving may be correlated with the decrease of DAT levels in striatum. Section3Comparison of striatal dopamine transporter levels in chronic heroin dependent subjects and methamphetamine dependent subjects[Objective] There are no studies directly comparing the dopamine transporter (DAT) level of heroin and methamphetamine (METH) by human. To compare the effect of heroin and METH addiction on DAT in the same dose and duration, we assessed the DAT levels in the striatum by99mTc-TRODAT-1single photon emission computed tomography (SPECT) brain imaging in people with heroin and METH dependence.[Methods] We recruited healthy human controls (n=21), heroin dependent subjects (n=23), and METH abusers (n=25). The heroin and METH dependent subjects exhibited negative urine toxicology after undergoing physiological detoxification for two weeks. All subjects underwent SPECT brain imaging after two weeks abstinence. SPECT scans performed at2-3hours after the intravenous injection of99mTc-TRODAT-1. Specific tracer uptake was assessed bilaterally in the regions of interest (ROIs), namely, the striatum, the caudate nucleus, and the putamen.[Results] A significant SURs reduction in heroin dependent subjects and METH dependent subjects compared with healthy controls was found in left striatum (1.97±0.41vs1.33±0.17vs1.24±0.31; F=35.79, P<0.05), right striatum (1.99±0.39vs1.28±0.19vs1.23±0.33; F=40.13, P<0.05), left caudate nucleus (2.01±0.42vs1.32±0.16vs1.26±0.33; F=38.11, P<0.05), right caudate nucleus (2.05±0.41vs1.27±0.19vs1.25±0.35; F=42.07, P<0.05), left putamen (1.91±0.40vs1.33±0.18vs1.22±0.31; F=32.38, P<0.05), and right putamen (1.93±0.38vs1.28±0.19vs1.22±0.32; F=37.12, P<0.05). There were no significant differences between heroin group and METH group in left striatum (P=0.32), right striatum (P=0.64), left caudate nucleus (P=0.53), right caudate nucleus (P=0.82), left putamen (P=0.21), and right putamen (P=0.52). The scores of craving, HAMA in heroin abusers were lower the Meth abusers (t=-4.29, P<0.05; t=-2.27, P<0.05).[Conclusions] Our results indicated that people with heroin dependence and METH dependence who are currently abstinent had lower DAT levels in striatum than healthy controls. Chronic heroin and METH abuse may cause damage to striatal dopamine neurons. There were no differences in striatal DAT in heroin and METH users. These results suggest that heroin and METH appear to produce similar effects in striatal DAT in humans.