Impacts of the different tissue specificities of the acupoints on electroacupuncture sensations

ObjectiveTo evaluate the influence of the tissue specificity of the acupoints (different meridians, tissues and nerve segments) on the frequency, intensity and current flow output in association with electroacupuncture (EA) sensations.MethodsTwenty one volunteers received EA. According to the tissue specificities of acupoints, 5 acupoint pairs were selected, named Zùsānl ( ST 36) vs Yánglíngquán ( GB 34, different meridians), Nèiguān ( PC 6) vs Dàlíng ( PC 7, different tissues), Zùsānl ( ST 36) vs Shudào ( ST 28, different nerve segments), Guānyuán ( CV 4) vs Zhōngwán ( CV 12, different nerve segments), and Zùsānl ( ST 36) vs Guānyuán( CV 4, different meridians, tissues and nerve segments). The electric frequency was 15 Hz. The electric current was under the subject's tolerance without sharp pain induced. EA lasted 90 s with 3 discontinuities. The sensations, such as soreness, numbness, fullness/distention, heaviness, tingling, pressure, dull pain, hotness and coldness were recorded as well as the current flow output in association with the needling sensations. The differences in the frequency, intensity and current flow output relevant with the needling sensations were compared among the different acupoint pairs.ResultsThere were no significant differences in the frequency of the needling sensations among the different acupoint pairs (all P<0.05). Of 9 different sensations of EA, fullness/distention, numbness and soreness presented the most commonly and remarkably; heaviness, pressure and tingling were on the second top; dull pain, hotness and coldness occurred at the lower frequency. There were the differences in the intensity of some needling sensations among the acupoint pairs, in which, the intensity of soreness, fullness/distention and heaviness was stronger at Zùsānl ( ST 36) vs Shudào ( ST 28) (all P<0.05); the intensity of fullness/distention, and numbness was stronger at Zùsānl ( ST 36) vs Guānyuán ( CV 4) P<0.01); the intensity of fullness/distention was stronger at Guānyuán ( CV 4) vs Zhōngwn ( CV 12) (P<0.05). The current flow output of EA was similar among the acupoint pairs (all P<0.05).ConclusionIn the situation that there is no obvious difference in the current flow output associated with EA sensations, the frequency of EA sensations does not relevant apparently with the different tissues. The difference in the intensity of the needling sensations among the different acupoints is probably relevant with the nerve segments at the acupoint locations. The frequency and the intensity of the different needling sensations at the same acupoint are relatively stable at the different times of EA.