OPTIMAL CONDITIONS FOR ELICITING MAXIMAL ELECTROACUPUNCTURE ANALGESIAWITH DENSE-AND-DISPERSE MODE STIMULATION

Our previous studies have suggested that dense-and-disperse (D-D) mode electroacupuncture (EA) elicited a more potent analgesic effect as co mpared to fixed-frequency EA stimulation. The present study was design ed to characterize the optimal conditions of D-D mode stimulation for maximal analgesia. The results were as follows: 1) The time period in which disperse frequency (2 Hz) was alternated with dense frequency (1 5 Hz or 100 Hz) was set at 2, 4, 5, 6, 8 and 10 seconds, respectively; maximal analgesic effect was obtained at 5 or 6 sec. per cycle; 2) Th e intensity was set at 1, 2 and 3 mA, respectively; maximal analgesic effect was obtained at 3 mA; 3) The analgesic effect induced by D-D mo de (2/15 Hz or 2/100 Hz) stimulation was significantly higher than tha t induced by fixed-frequency stimulation (2, 15 and 100 Hz); 4) The an algesic effect induced by D-D mode (2/15 Hz or 2/100 Hz) could be bloc ked partially and significantly by a large dose of opioid antagonist n aloxone (10 mg/kg), suggesting that kappa opioid receptors participate in D-D mode (2/15 Hz or 2/100 Hz) EA analgesia.