A novel technique to study the brain's response to pain: proton magnetic resonance spectroscopy.
Glutamate, a major excitatory neurotransmitter, has been implicated as an important mediator in the neurotransmission, potentiation, and negative affect associated with pain. We present results showing that a painful stimulus elicits a dynamic increase in glutamate (9.3% from baseline) concentrations in the anterior cingulate cortex, detectable using proton Magnetic Resonance Spectroscopy ((1)H-MRS). Increases in glutamine levels were also seen, which correlate strongly with the subjective level of pain experienced by participants (r(2) = 0.58, P < 0.01). These novel findings are the first time a dynamic change in glutamate and glutamine levels from baseline in response to an external stimuli has been measured in a single proton MRS scanning session. As such, this report demonstrates the efficacy of (1)H-MRS as a non-invasive tool for the study of neural responses to pain in vivo. The paradigm used in this study demonstrates that dynamic glutamate/glutamine changes due to stimulation are measurable by proton MRS, and could provide a means of testing novel pharmaceutical agents and other treatments for chronic pain.
Mullins
Paul G
PG
The MIND Imaging Center, a collaboration of the MIND Institute and the University of New Mexico, Albuquerque, 87131, USA.
Rowland
Laura M
LM
Jung
Rex E
RE
Sibbitt
Wilmer L
WL
D000328:Adult; D001921:Brain / Q000473:pathology* / Q000503:physiopathology; D001923:Brain Chemistry / Q000502:physiology; D003080:Cold Temperature; D005260:Female; D018698:Glutamic Acid / Q000502:physiology; D005973:Glutamine / Q000502:physiology; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D010146:Pain / Q000473:pathology* / Q000503:physiopathology; D010147:Pain Measurement; D011312:Pressure; D011522:Protons; D009435:Synaptic Transmission / Q000502:physiology
D011522:Protons; D005973:Glutamine; D018698:Glutamic Acid