INCREASED PAIN THRESHOLD FOLLOWING ELECTROACUPUNCTURE - ANALGESIA IS INDUCED MAINLY IN MERIDIAN ACUPUNCTURE POINTS

Pain thresholds were determined before and after electroacupuncture of the dorsal aspect acupuncture points (AP) of the hand and non acupunc ture points (NAP) located 15 mm from the traditional acupuncture point s to assess changes in pain threshold thus provoked. Methods. in eight volunteers the pain threshold of specific points was determined befor e and after acupuncture in the Hegu point (L.I. 4), at the back of the hand. A pressure dolorimeter was used to evaluate pain threshold at t he Yangxi (L.I. 5) and Quchi (L.I. 11) points and at sites 15 mm from them. The effects on pain threshold were also measured at Yingxiang (L .I. 20) on both sides. Results. Before electrostimulation there were n o significant differences among the pain thresholds in both AP and NAP . After electrostimulation of the Yangxi point, pain threshold raised from 5.20 kg/sq.cm to 9.20 kg/sq.cm (p<0.01); acupuncture at Quchi cau sed the threshold to increase from 5.36 kg/sq.cm to 9.20 kg/sq.cm (p<0 .01) and Yingxiang stimulation changed threshold from 2.63 kg/sq.cm to 3.83 kg/sq.cm (p<0.051) at the point on the same side and from 2.26 k g/sq.cm to 3.90 kg/sq.cm (p<0.05) in the opposite side. Before electro acupuncture the pain thresholds at all the tested sites were not stati stically different (p>0.1). After electrostimulation the pain threshol d increased 77% at L.I. 5 but went up just 9% and 6% 15 mm from L.I. 5 (p<0.01); threshold increased by 70% at L.I. 11 but only by 6% and 7% (p<0.01) 15 mm from L.I. 11. Conclusions. The pain threshold increase d significantly in all tested sites after electroacupuncture but the a nalgesic effect was predominant in those points lying along the acupun cture meridians.