Cocaine and methamphetamine induce opposing changes in BOLD signal response in rats.
Neuroimaging studies in psychostimulant addicts have reported functional neural activity changes in brain regions involved in relapse. However, the difference between the effects of the psychostimulants methamphetamine and cocaine on neuronal activity in a similar setting not been clarified. Since studies in humans are limited by the inability to study the initial impact of psychostimulant drugs, we addressed this issue in a rat model.



Here, we report methamphetamine and cocaine-induced blood-oxygen-level dependent (BOLD) signal change using functional magnetic resonance imaging (fMRI) in rats receiving drug for the first time during the imaging session.



Twenty-three male Long Evans rats underwent fMRI imaging and received an intravenous infusion of methamphetamine, cocaine, or saline. Anatomical and pharmacological fMRI (pfMRI) were performed on a 7T BioSpec dedicated research MR scanner under isoflurane gas (1.5-2%). After collecting baseline data for 10min, rats received drug over the next 10min for a total 40min scan time. Data were then preprocessed and statistically analyzed in anatomically defined regions of interest (ROIs) that have been implicated in persistent drug seeking and relapse.



Methamphetamine during the imaging session resulted in a sustained negative BOLD signal change in key regions of the relapse circuit, except for the prefrontal cortex. In contrast, cocaine evoked a positive or unchanged BOLD signal in these same regions. In all of the investigated ROIs, there were no changes in BOLD signal following saline.



Acute methamphetamine and cocaine have distinct patterns of functional activity as measured by pfMRI.
Department of Pharmaceutical Sciences, University of South Florida, Tampa FL 33612.
Saeid
S
Taheri
Department of Neurosciences, Medical University of South Carolina, Charleston SC 29425.
Zhu
Z
Xun
Department of Neurosciences, Medical University of South Carolina, Charleston SC 29425.
Ronald E
RE
See
Department of Neurosciences, Medical University of South Carolina, Charleston SC 29425.
Jane E
JE
Joseph
Department of Neurosciences, Medical University of South Carolina, Charleston SC 29425.
Carmela M
CM
Reichel
D061605:Administration, Intravenous; D019969:Amphetamine-Related Disorders / Q000503:physiopathology; D018685:Anesthetics, Inhalation / Q000494:pharmacology; D000818:Animals; D001921:Brain / Q000000981:diagnostic imaging / Q000187:drug effects* / Q000503:physiopathology*; D001931:Brain Mapping; D000697:Central Nervous System Stimulants / Q000494:pharmacology*; D002560:Cerebrovascular Circulation / Q000187:drug effects / Q000502:physiology; D003042:Cocaine / Q000494:pharmacology*; D019970:Cocaine-Related Disorders / Q000503:physiopathology; D018765:Dopamine Uptake Inhibitors / Q000494:pharmacology*; D058999:Drug-Seeking Behavior / Q000187:drug effects / Q000502:physiology; D007530:Isoflurane / Q000494:pharmacology; D008279:Magnetic Resonance Imaging; D008297:Male; D008694:Methamphetamine / Q000494:pharmacology*; D010100:Oxygen / Q000097:blood; D020318:Rats, Long-Evans
D018685:Anesthetics, Inhalation; D000697:Central Nervous System Stimulants; D018765:Dopamine Uptake Inhibitors; D008694:Methamphetamine; D007530:Isoflurane; D003042:Cocaine; D010100:Oxygen
Addiction; Blood-oxygenation-level dependent (BOLD) signal; Cocaine; Methamphetamine; Pharmaco-functional MRI