The central effect of electro-acupuncture analgesia on visceral pain of rats: a study using the [3H] 2-deoxyglucose...

This study had the objective to understand the central effect of electro-acupuncture analgesia (EAA) on visceral pain of rats. We used the method of Sokoloff's 2-deoxyglucose (2-DG) auto-radiographic quantitative analysis to observe the changes of local cerebral metabolic rate of glucose (LCMRG) in rats given electrical stimulation of greater splanchnic nerve (GSN) followed by electro-acupuncture. From the results of this study, we found that the LCMRG had a significant difference between EAA group and pain group at some structures, such as the spinal thoracic and lumbar dorsal horns (segments T6-T8, L1-L3), locus coeruleus (lc), nucleus raphe magnus (rm), nucleus reticular gigantocellularis (rgi), periaqueductal gray (PAG) and habenulae lateralis (hl) of thalanum. The results combining reports by other investigators, suggest that these local cerebral structures might be the key nuclei in EAA on visceral pain.