Acupuncture attenuates extracellular glutamate level in global ischemia model of rat

Acupuncture has been known to be effective in ischemia, and glutamate excitotoxicity is an important factor for the neuronal cell death. We examined the effect of acupuncture on glutamate level in the ischemic stroke model.

A global ischemia was induced using the method of 11-vessel occlusion in rat. Rats were randomly divided into two groups: the control group (n=5, with 11-vessel occlusion) and the acupuncture group (n=5, with 11-vessel occlusion + acupuncture). The extracellular glutamate level was assessed using an intracerebral biosensor system measuring 256 samples per second. Simultaneously, the cerebral blood flow was measured and the electroencephalogram data were recorded. The time schedule of the experiment was as follows: 10 minutes of baseline measurement, 10 minutes of occlusion and 30 minutes of follow-up monitoring. Acupuncture stimulation was applied to the acupuncture points GB34 (Yangneungcheon) and GB39 (Hyeonjong) during the occlusion period.

In the control group, the extracellular glutamate level was changed as 135.19 +/- 23.76 microM (mean +/- standard deviation) from the baseline level. However, this increase was suppressed in the acupuncture group (72.20 +/- 27.15 microM, p<0.01 versus the control group). The changes of cerebral blood flow and electroencephalogram were not significantly different between the groups.

This result suggests that the effect of acupuncture might be closely associated with modulation of the brain glutamate release in the ischemic condition.