Disruption of glial function regulates the effects of electro-acupuncture at Tsusanli on gastric activity in rats

Neuromechanism of acupuncture regulating gastrointestinal motility

Acupuncture has been used in China for thousands of years and has become more widely accepted by doctors and patients around the world. A large number of clinical studies and animal experiments have confirmed that acupuncture has a benign adjustment effect on gastrointestinal (GI) movement; however, the mechanism of this effect is unclear, especially in terms of neural mechanisms, and there are still many areas that require further exploration. This article reviews the recent data on the neural mechanism of acupuncture on GI movements. We summarize the neural mechanism of acupuncture on GI movement from four aspects: acupuncture signal transmission, the sympathetic and parasympathetic nervous system, the enteric nervous system, and the central nervous system.

Effect of Electroacupuncture at ST36 on Gastric-Related Neurons in Spinal Dorsal Horn and Nucleus Tractus Solitarius

The aim of this study was to observe the effect of electroacupuncture (EA) at the ST36 acupoint on the firing rate of gastric-related neurons in the spinal dorsal horn (SDH) and nucleus tractus solitarius (NTS). There were different effects of gastric distention in SDH and NTS in 46 male Sprague-Dawley rats. In 10 excitatory neurons in SDH, most of the neurons were inhibited by homolateral EA. The firing rates decreased significantly (P < 0.05) in 10 excitatory gastric-related neurons in NTS; the firing rates of 6 neurons were further excited by homolateral EA, with a significant increase of the firing rates (P < 0.05); all inhibitory gastric-related neurons in NTS were excited by EA. The inhibition rate of homolateral EA was significantly increased in comparison with contralateral EA in gastric-related neurons of SDH (P < 0.05). There was no significant difference between homolateral and contralateral EA in gastric-related neurons of NTS. EA at ST36 changes the firing rate of gastric-related neurons in SDH and NTS. However, there are some differences in responsive mode in these neurons. The existence of these differences could be one of the physiological foundations of diversity and complexity in EA effects.

The Neural Mechanism by Which the Dorsal Vagal Complex Mediates the Regulation of the Gastric Motility by Weishu (RN12) and Zhongwan (BL21) Stimulation

A large number of studies have been conducted to explore the mechanism of Back-Shu and Front-Mu points. While several lines of evidence addressed the acupuncture information of Shu acupoints and Mu acupoints gathering in the spinal cord, whether the convergence is extended to the high centre still remains unclear. The study selected gastric Mu points (RN12) and gastric Shu points (BL21) regulating gastric motility and its central neural mechanisms as the breakthrough point, using the technique of immunochemistry, nuclei lesion, electrophysiology, and nerve transection. Here, we report that gastric motility regulation of gastric Shu and Mu acupoints and their synergistic effect and the signals induced by electroacupuncture (EA) stimulation of acupoints RN12 and RN12 gather in the dorsal vagal complex (DVC), increasing the levels of gastrointestinal hormones in the DVC to regulate gastric motility through the vagus. In sum, our data demonstrate an important role of DVC and vagus in the regulation of gastric motility by EA at gastric Shu and Mu points.

Effects and possible mechanisms of acupuncture at ST36 on upper and lower abdominal symptoms induced by rectal distension in healthy volunteers

Background acupuncture (AP) has been shown to have a therapeutic potential for gastrointestinal motility disorders. The aims of this study were to investigate the effects and possible mechanisms of acupuncture on postprandial upper and lower abdominal symptoms induced by rectal distension (RD). Twenty healthy volunteers were involved in a two-session study (AP and sham-AP, AP and no-AP, or sham-AP and no-AP). In 12 of the volunteers, RD was performed for 60 min in the postprandial state, and AP at ST36 or sham-AP was performed during the second 30-min period of RD. Gastric slow waves and heart rate variability (HRV) were recorded using the electrogastrogram and electrocardiogram, respectively. Upper and lower abdominal symptoms were scored during RD with AP and sham-AP. In five of the subjects, an additional experiment with two sessions (with AP and no-AP) was performed. In the remaining eight volunteers, the same experiment was performed with sham-AP and no-AP was performed. The results were, first, RD at an average volume of 171 ml induced upper and lower abdominal symptoms (P < 0.01). AP, but not sham-AP or no-AP, reduced both upper and lower abdominal symptoms (P < 0.05). Second, RD decreased the percentage of normal gastric slow waves (P < 0.05). AP improved gastric slow waves compared with sham-AP or no-AP (P < 0.05). Third, in the larger, but not smaller, sample size experiment, the vagal activity during the RD plus AP period was significantly higher than that during the RD alone period in the same session and the corresponding period with sham-AP or no-AP in other sessions (P < 0.05). Neither sham-AP nor no-AP showed any effects on vagal activity (P > 0.05). Finally, in the experiment with eight volunteers, neither sham-AP nor no-AP showed any effects on RD-induced impairment in gastric slow waves, abdominal symptoms, or vagal activity (P > 0.05). The conclusions are RD induces upper or lower abdominal symptoms and impairs gastric slow waves in healthy volunteers. AP at ST36 is able to improve upper and lower abdominal symptoms and impaired gastric slow waves induced by RD, possibly mediated via the vagal pathway.