The Effects Of High Frequence Electro-Acupuncture Stimulation At ST-36 On Colonic Motility In Rats

ObjectiveTo observe the change of colonic transit and propulsive movement of rats by high frequency electro-acupuncture stimulation (EAS) at acupuncture point ST-36 (Zusanli) and validate further that high frequency EAS at ST-36 might promote colonic motility.Methods44 adult male Sprague-Dawley rats were all implanted with special tubes in the proximal colons by operation and randomly divided into four groups: the control group (groupⅠ,N=11), the acupuncture at ST-36 group (groupⅡ, N=11), the sham electroacupuncture group (groupⅢ, N=11) and the EAS at ST-36 group (groupⅣ, N=11). The parameter of the EAS was set at 100Hz, 3mA. In the experiment, 1.5ml phenol-red solution (0.5mg/ml) was used as non-absorptive marker and the colonic transit of rats were assessed by determining the volume of discharged phenol-red every 10min in 90min. And before the operation, one plastic bead (3mm in diameter) was pushed 3cm into the rectums of the rats (groupⅡ,ⅢandⅣ) by slender flextubing and the time to bead excretion under normal and corresponding stimulation circumstance were respectively recorded.Resultsa. As compared to groupⅠandⅡ, the colonic transit of groupⅣwere obviously promoted in 20-90min and the difference was significant (P<0.05). The colonic transit of groupⅢwere enhanced only in 20-40min and 60min compared with groupⅠ(P<0.05). The ratio of discharging phenol-red in groupⅣwere increased significantly, as contrast to groupⅢ, in 50min and 70-90min (P<0.05).b. The time to bead excretion under stimulation condition was shortened about 27% in groupⅣas compared to the time under normal condition and the difference was significant (1142.8±123.9 vs 1563.5±155.9, P<0.01). Whereas, the difference of the time to excretion before and after stimulation of groupⅡand groupⅢwere not significant (P>0.05).ConclusionsThe role of promoting colonic transit and propulsive movement was continue and strong by using high frequence EAS at ST-36 and just temporal and less stronger at non-acupoint. And the temporal promoting effect of EAS at non-acupoint on colonic transit might be related with the stress reaction produced by high frequence electric stimulation.