Electroacupuncture via chronically implanted electrodes improves gastrointestinal motility by balancing sympathovagal activities in a rat model of constipation

Electroacupuncture (EA) has been reported for treating constipation in clinical studies. However, little is known of the possible mechanisms involved in the prokinetic effect of EA. The aim of this study was to investigate the effects and underlying autonomic mechanisms of EA via chronically implanted electrodes for constipation in rat induced by Loperamide (Lop). Lop was given to regular rats to induce constipation. EA was performed via a pair of electrodes chronically implanted at bilateral acupoint ST-36. Feces characteristics, gastric emptying, small intestinal transit, distal colon transit time (dCTT), and whole gut transit time (WGTT) were measured in various sessions with EA or sham EA in rats with constipation induced by Lop. Heart rate variability (HRV) derived from the electrocardiogram was analyzed to evaluate autonomic functions. The number of fecal pellets was reduced by 27% with Lop ( P < 0.01) and normalized by 7-day EA. Similar results were also observed in pellet weight. In normal rats compared with sham EA, EA shortened dCTT by 74% ( P < 0.05 vs. sham EA), increased small intestinal transit by 28% ( P < 0.01) and gastric emptying by 27% ( P < 0.05), and accelerated whole gut transit by 14% ( P < 0.05). In Lop-treated rats, the dCTT and WGTT were prolonged by Lop and normalized by EA. Lop significantly decreased vagal activity and increased sympathetic nerve activity; however, EA reversed these effects. EA at ST-36 via chronically implanted electrodes improves Lop-induced constipation by enhancing GI motility via the autonomic mechanisms. NEW & NOTEWORTHY The findings of the present study suggest that the proposed electroacupuncture (EA) may have great therapeutic potential for treating patients with opioid-induced constipation. It was demonstrated that EA at ST-36 improved transit of every organ along the gut mediated via the autonomic mechanisms in normal rats and rats with Lop-induced constipation. It is advised to administrate EA daily instead of two or three times weekly as reported in most of the clinical studies.

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Ameliorating effects and mechanisms of electroacupuncture on gastric dysrhythmia, delayed emptying, and impaired accommodation in diabetic rats

AJP Gastrointestinal and Liver Physiology ◽

10.1152/ajpgi.00252.2009 ◽

2010 ◽

Vol 298 (4) ◽

pp. G563-G570 ◽

Cited By ~ 68

Author(s):

Jieyun Yin ◽

Jie Chen ◽

Jiande D. Z. Chen

Keyword(s):

Therapeutic Potential ◽

Diabetic Rats ◽

Intestinal Transit ◽

Vagal Activity ◽

Gastric Accommodation ◽

Small Intestinal Transit ◽

Gastric Dysrhythmia ◽

Gastric Slow Wave ◽

Normal Percentage ◽

Small Intestinal

The aim of this study was to investigate the effects and mechanisms of electroacupuncture (EA) on gastric accommodation, gastric dysrhythmia, and gastric emptying (GE) in streptozotocin (STZ)-induced diabetic rats. Five experiments were performed in five groups of STZ-induced diabetic rats to study the effects of EA at ST-36 (Zusanli) on gastric slow-wave dysrhythmia, delayed GE and intestinal transit, impaired gastric accommodation, and the mechanisms of EA involving the autonomic and opioidergic pathways. We found the following: 1) EA improved gastric dysrhythmia in the diabetic rats. The normal percentage of slow waves was 55.4 ± 2.9% at baseline and significantly increased to 69.2 ± 2.2% with EA ( P = 0.01); this effect was blocked by naloxone. 2) EA resulted in a 21.4% increase in GE and 18.2% increase in small intestinal transit in the diabetic rats. 3) EA restored diabetes-induced impairment in gastric accommodation. Gastric accommodation was 0.98 ± 0.13 ml with sham EA and significantly increased to 1.21 ± 0.15 ml with EA ( P = 0.01), and this effect was blocked by naloxone. 4) EA increased vagal activity assessed by the spectral analysis of the heart rate variability. We concluded that EA at ST-36 improves gastric dysrhythmia, delayed GE and intestinal transit, and impaired accommodation in STZ-induced diabetic rats, and the improvement seems to be mainly mediated via the vagal pathway. EA may have a promising therapeutic potential for diabetic gastroparesis.

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