Neurochemical adaptation to cocaine abuse: reduction of N-acetyl aspartate in thalamus of human cocaine abusers.
BACKGROUND
The aim of this study was to determine the existence of, and possible mechanisms for, chronic cocaine use-induced neurotoxicity in the human brain. Because in vivo magnetic resonance spectroscopy (MRS) provides a noninvasive way to detect biochemical and physiological changes in the brain, we sought to specifically determine the neurochemical adaptations in chronic cocaine-dependent subjects.


METHODS
Twenty-one cocaine users and 13 non-drug-using, age-matched normal volunteers were recruited for an in vivo proton MRS study. Following screening that included physical examination, histories, and blood testing, cocaine group subjects received a spectral scan on a 1.5-T GE Signa scanner. Spectra were obtained from the left basal ganglia and/or the left thalamus from subjects in both groups using an rf bird-cage type head coil with single-voxel localization.


RESULTS
The level of N-acetyl aspartate in the region of left thalamus was lower (17%) in the chronic cocaine user group but not in the region of left basal ganglia, compared with the control group.


CONCLUSIONS
These results suggest that chronic cocaine use may induce abnormal neurochemical activity and a state of neuronal dysregulation and/or neurotoxicity. It will now be important to determine if these alterations are reversible during withdrawal and what the functional implications of this observation are with respect to cognitive function and drug relapse.
Li
S J
SJ
Biophysics Research Institute, Medical College of Wisconsin, Milwaukee 53226-0509, USA.
Wang
Y
Y
Pankiewicz
J
J
Stein
E A
EA
D000328:Adult; D001224:Aspartic Acid / Q000031:analogs & derivatives* / Q000378:metabolism; D001479:Basal Ganglia / Q000378:metabolism; D015415:Biomarkers; D001923:Brain Chemistry / Q000187:drug effects; D016022:Case-Control Studies; D002794:Choline / Q000378:metabolism; D002908:Chronic Disease; D003042:Cocaine / Q000009:adverse effects; D019970:Cocaine-Related Disorders / Q000378:metabolism*; D003401:Creatine / Q000378:metabolism; D018765:Dopamine Uptake Inhibitors / Q000009:adverse effects; D005260:Female; D006801:Humans; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D013788:Thalamus / Q000378:metabolism*
D015415:Biomarkers; D018765:Dopamine Uptake Inhibitors; D001224:Aspartic Acid; C000179:N-acetylaspartate; D003042:Cocaine; D003401:Creatine; D002794:Choline