POSTER PRESENTATION ABSTRACTS
Please note: All posters will be displayed in Salons 10-12.

FRIDAY, 5:45-6:30 PM

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Ren JQ, Xu HB, Kwong KK, Hui KKS, Rosen BR, ChenYI*.

Acupuncture effects on striatal glutamate, GABA, and dopaminergic activity --- an fMRI and microdialysis study.

Martinos Center for Biomedical Imaging of radiology, Massachusetts General Hospital iris@nmr.mgh.harvard.edu *Presenting author

PROCEDURE: Acupuncture is an ancient healing art with controversial opinions and evidences on its clinical efficacy in modern medicine. In this study, we tested the acupuncture effects on the dopamine (DA), glutamate (Glu) and gamma-aminobutyric acid (GABA) function in the striatum. Perturbation of those neurotransmitter levels under normal physiological condition is typically small and acupuncture may not induce great modulation on their synaptic concentrations. We hypothesize that acupuncture manipulation on a highly deviated DA level will lead to a more prominent effect on those three neurotransmitters. To achieve this goal, we used D-amphetamine (AMPH) to induce massive DA release in the striatum. We than applied electrical forepaw stimulation (EFS) at a classic acupoint to study the perturbation on the DA, Glu, and GABA releases in the striatum. Neurotransmitter concentrations were assessed by microdialysis and correlated to the MR measured regional cerebral blood volume (rCBV) changes. This study shall advance our understanding on how acupuncture works at level of the central nervous system.

METHODS: Sprague-Dawley rats receiving 1% halothane anesthesia were used in this study. EFS: Electrodes were placed at acupoint LI4 on the forepaw and subcutaneously on the same limb. Electrical current (2Hz/1mA for 20 mins) was delivered 20 minutes after the bolus administration of AMPH (3mg/kg iv). MRI: rCBV information was acquired in a 9.4T or a 4.7T MR scanner using IRON method. Microdialysis: Dialysate samples were obtained from the dorsolateral striatum (10min/sample).

RESULTS: Glutamate: AMPH alone decreased Glu release which was later reversed to a positive release by EFS. GABA: EFS prolonged the AMPH-induced GABA increase. DA: EFS attenuated the AMPH-induced DA increase. This EFS-induced DA concentration attenuation was correlated to the MR measurement of rCBV changes.

CONCLUSIONS: This preliminary data suggests that EFS could be stimulating the corticostriatal Glu neurons to produce extra Glu release in the striatum. The increased striatal Glu would augment the interneuron release of GABA, which in turn would inhibit the AMPH-induced DA release.

 

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