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.