Effects and mechanisms of auricular electroacupuncture on gastric hypersensitivity in a rodent model of functional dyspepsia

Abstract

BackgroundFunctional dyspepsia (FD) is a common functional gastrointestinal disease, and abdominal pain is one of the main symptoms. The aim of this study was to explore the effects and mechanisms of auricular electro-acupuncture (AEA) on gastric hypersensitivity in a rodent model of FD.MethodsTen-day-old pups were gavaged with 0.2 ml of 0.1% iodoacetamide daily for 6 days. AEA at the “stomach” point with different parameters or sham-EA was performed on 8-week-old animals. Gastric sensitivity to gastric distention was measured under different conditions. Autonomic functions were assessed from the spectral analysis of heart rate variability (HRV) derived from the electrocardiogram. Naloxone was injected intraperitoneally before AEA to explore the opioid mechanism. Gastric emptying was measured at the end of the study.Results1) Gastric sensitivity to gastric distention was higher in the FD rats. AEA with parameters of 0.1s on, 0.4s off, 100Hz, 0.3ms and 0.4–0.5mA, but not other parameters or sham-EA, decreased gastric hypersensitivity in the FD rats. Naloxone did not block the effect of AEA. 2) Lower vagal activity and higher sympathovagal ratio were noted in the FD rats, compared with the controls. AEA increased vagal activity and improved sympathovagal imbalance.ConclusionsAEA ameliorates gastric hypersensitivity in FD rats and this effect may be attributed to the improvement of sympathovagal balance.

Ameliorating Effects of Electroacupuncture on Dysmotility, Inflammation, and Pain Mediated via the Autonomic Mechanism in a Rat Model of Postoperative Ileus

“…These parameters have been shown to reduce gastric hypersensitivity 20 and ameliorate visceral pain in a rodent model of functional dyspepsia. 21 From Figure 7, it is clear that abdominal surgery induced pain, but the pain gradually subsided because there was a significant decrease in the RGS score: pain score starting at 2 hours after the surgery in the control rats. IM, however, delayed this pain recovery by 1 hour; the decrease in the pain score was significant only at 3 hours after the surgery.…”

“…9,10,13,14,17 EA at PC6 was used to mainly provide an analgesic effect and the best stimulation parameters to reduce visceral pain were: on time of 0.1 seconds, off time of 0.4 seconds, 0.5 milliseconds, 100 Hz, and 1 mA. 20,21 Sham-EA was performed in Sham-EA rats. The procedure was the same as EA without electrical stimulation.…”

Electroacupuncture for the treatment of functional dyspepsia

“…[ 27 ] Zhou J et al found that auricular EA can improve the gastric sensitivity of FD rats by improving the balance of sympathetic vagus nerve. [ 24 ] Various clinical studies have reported that the improvement effect of EA on gastric dysrhythmia is consistent and repeatable, suggesting that EA has a strong effect on the treatment of gastric slow-wave dysrhythmia. [ 28 – 30 ]…”

Electroacupuncture treatments for gut motility disorders

“…A few major mechanisms involved in the analgesic effect of EA on visceral pain or hypersensitivity have been reported: sensory afferent mechanisms involving dorsal root ganglions and opioid mechanisms and vagally mediated mechanisms . It should also be noted that EA stimulation parameters for treating visceral pain may be distinctly different from those used for treating gut dysmotility …”

“…38 It should also be noted that EA stimulation parameters for treating visceral pain may be distinctly different from those used for treating gut dysmotility. 21,39…”