Despite a wealth of preclinical information on stimulant-induced adaptations (plasticity or toxicity) in the CNS, the translation of that knowledge to clinical neuroscience has been hampered by the inability to accurately assess human brain function in vivo. The advent of magnetic resonance (MR) neuroimaging techniques, with increasingly high-resolution and sensitivity, has revolutionized research strategies in studies of human substance abusers. However the physiological significance of MR-derived measures in humans is not yet fully understood. In fact, preclinical MR studies of CNS function lag far behind the number of MR studies with humans, despite the fact that preclinical studies are amenable to controlled pharmacological manipulation and independent verification. With an emphasis on stimulant abuse, the present proposal addresses the physiological significance of several neurochemicals that can be measured with proton MR spectroscopy (1H-MRS). By applying state-of-the-art MR techniques (at 11.7 T) to proven paradigms of drug study, the results should provide 1) novel insight into the neurobiology and neurotoxicology of acute and repeated exposure to stimulants, and 2) interpretations and hypotheses that can be directly translated into clinical utility. In an effort to validate the physiological significance of MR-visible compounds, a major objective of the research plan is to use high-resolution magic angle spinning (HR-MAS) 1H-MRS to determine ex vivo the basic neuropharmacology of the MR-visible neurochemical profile in rat brain. Thus, in discrete monoamine-related areas of the rat brain, we plan to determine the effect of in vivo pretreatment with 1) specific neurotoxins, 2) three psychostimulants with distinct mechanisms of action (MDMA, cocaine, and methamphetamine), and 3) D1 and 5HT2 receptor ligands on the MR-visible neurochemical profile. In each case, direct comparisons will be made between the 1H-MRS observations and those determined with HPLC-EC. Neurochemicals that are readily measured by HR-MAS 1H-MRS reflect several key cellular functions including neuronal viability (Nacetylaspartate), neurotransmission (glutamate, glutamine, GABA), energy status (lactate, creatine), 2 nd-messenger pathways (myo-inositol), and membrane phospholipid metabolism (phosphocholine and glycerophosphocholine). After establishing the pharmacological and physiological parameters that modulate the MR-visible neurochemical profile, a series of experiments will use in vivo 1H-MRS and MRI (at 11.7 T) to determine the longitudinal effects of stimulant exposure. A critical component of validating the in vivo observations will be a direct comparison to the results obtained with HR-MAS 1H-MRS. MRI T2 images, water diffusion maps, and in vivo neurochemistry obtained in a longitudinal design in vivo, are expected to define regionally selective lesions following drug exposure. MDMA abuse has increased unabated in adolescents, despite convincing evidence that street doses are toxic to both 5HT and DA neurons in rodents and monkeys, up to 7 yrs after drug cessation. The potential loss of 5HT innervation subsequent to MDMA exposure may have profound effects on the emergence of mood disorders in the relatively young cohort of MDMA users. Increased use, combined with preclinical toxicity, speaks to the necessity to resolve the question of MDMA toxicity in humans. MR neuroimaging, especially 1H-MRS, provides a non-invasive window into human brain function. Development of a neurochemical fingerprint describing the effects of 3 stimulants will provide a solid basis for hypothesis-driven investigations of stimulant-induced plasticity and/or toxicity in the CNS.

Agency
National Institute of Health (NIH)
Institute
National Institute on Drug Abuse (NIDA)
Type
Research Project (R01)
Project #
1R01DA016736-01A1
Application #
6775943
Study Section
Neurobiology of Motivated Behavior Study Section (NMB)
Program Officer
Aigner, Thomas G
Project Start
2004-05-01
Project End
2008-03-31
Budget Start
2004-05-01
Budget End
2005-03-31
Support Year
1
Fiscal Year
2004
Total Cost
$287,057
Indirect Cost
Name
Wayne State University
Department
Psychiatry
Type
Schools of Medicine
DUNS #
001962224
City
Detroit
State
MI
Country
United States
Zip Code
48202
Fitzpatrick, Christopher J; Perrine, Shane A; Ghoddoussi, Farhad et al. (2016) Sign-trackers have elevated myo-inositol in the nucleus accumbens and ventral hippocampus following Pavlovian conditioned approach. J Neurochem 136:1196-1203
Eagle, Andrew L; Singh, Robby; Kohler, Robert J et al. (2015) Single prolonged stress effects on sensitization to cocaine and cocaine self-administration in rats. Behav Brain Res 284:218-24
Sajja, Venkata Siva Sai Sujith; Galloway, Matthew; Ghoddoussi, Farhad et al. (2013) Effects of blast-induced neurotrauma on the nucleus accumbens. J Neurosci Res 91:593-601
Bustillo, Juan; Galloway, Matthew P; Ghoddoussi, Farhad et al. (2012) Medial-frontal cortex hypometabolism in chronic phencyclidine exposed rats assessed by high resolution magic angle spin 11.7 T proton magnetic resonance spectroscopy. Neurochem Int 61:128-31
Perrine, Shane A; O'Leary-Moore, Shonagh K; Galloway, Matthew P et al. (2011) Binge toluene exposure alters glutamate, glutamine and GABA in the adolescent rat brain as measured by proton magnetic resonance spectroscopy. Drug Alcohol Depend 115:101-6
Perrine, Shane A; Ghoddoussi, Farhad; Michaels, Mark S et al. (2010) MDMA administration decreases serotonin but not N-acetylaspartate in the rat brain. Neurotoxicology 31:654-61
Cortese, Bernadette M; Mitchell, Todd R; Galloway, Matthew P et al. (2010) Region-specific alteration in brain glutamate: possible relationship to risk-taking behavior. Physiol Behav 99:445-50
Ghoddoussi, Farhad; Galloway, Matthew P; Jambekar, Amruta et al. (2010) Methionine sulfoximine, an inhibitor of glutamine synthetase, lowers brain glutamine and glutamate in a mouse model of ALS. J Neurol Sci 290:41-7
Knox, Dayan; Perrine, Shane A; George, Sophie A et al. (2010) Single prolonged stress decreases glutamate, glutamine, and creatine concentrations in the rat medial prefrontal cortex. Neurosci Lett 480:16-20
Perrine, Shane A; Michaels, Mark S; Ghoddoussi, Farhad et al. (2009) Cardiac effects of MDMA on the metabolic profile determined with 1H-magnetic resonance spectroscopy in the rat. NMR Biomed 22:419-25

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