RT Journal Article SR Electronic T1 Loss of Dopamine Transporters in Methamphetamine Abusers Recovers with Protracted Abstinence JF The Journal of Neuroscience JO J. Neurosci. FD Society for Neuroscience SP 9414 OP 9418 DO 10.1523/JNEUROSCI.21-23-09414.2001 VO 21 IS 23 A1 Volkow, Nora D. A1 Chang, Linda A1 Wang, Gene-Jack A1 Fowler, Joanna S. A1 Franceschi, Dinko A1 Sedler, Mark A1 Gatley, Samuel J. A1 Miller, Eric A1 Hitzemann, Robert A1 Ding, Yu-Shin A1 Logan, Jean YR 2001 UL http://www.jneurosci.org/content/21/23/9414.abstract AB Methamphetamine is a popular drug of abuse that is neurotoxic to dopamine (DA) terminals when administered to laboratory animals. Studies in methamphetamine abusers have also documented significant loss of DA transporters (used as markers of the DA terminal) that are associated with slower motor function and decreased memory. The extent to which the loss of DA transporters predisposes methamphetamine abusers to neurodegenerative disorders such as Parkinsonism is unclear and may depend in part on the degree of recovery. Here we assessed the effects of protracted abstinence on the loss of DA transporters in striatum, in methamphetamine abusers using positron emission tomography and [11C]d-threo-methylphenidate (DA transporter radioligand). Brain DA transporters in five methamphetamine abusers evaluated during short abstinence (<6 months) and then retested during protracted abstinence (12–17 months) showed significant increases with protracted abstinence (caudate, +19%; putamen, +16%). Although performance in some of the tests for which we observed an association with DA transporters showed some improvement, this effect was not significant. The DA transporter increases with abstinence could indicate that methamphetamine-induced DA transporter loss reflects temporary adaptive changes (i.e., downregulation), that the loss reflects DA terminal damage but that terminals can recover, or that remaining viable terminals increase synaptic arborization. Because neuropsychological tests did not improve to the same extent, this suggests that the increase of the DA transporters was not sufficient for complete function recovery. These findings have treatment implications because they suggest that protracted abstinence may reverse some of methamphetamine-induced alterations in brain DA terminals.