Needleless transcutaneous electroacupuncture improves rectal distension-induced impairment in intestinal motility and slow waves via vagal mechanisms in dogs

摘要

Aim: This study was designed to compare the effects and mechanisms of transcutaneous electroacupuncture (TEA) on rectal distention (RD)-induced intestinal dysmotility with EA. Methods: six female dogs chronically implanted with a duodenal fistula, a proximal colon fistula and intestinal serosal electrodes were studied. EA and TEA were performed via needles and cutaneous electrodes placed at bilateral ST-36 (Zusanli) acupoints respectively; their effects on postprandial intestinal dysmotility (slow waves, contractions and transit) induced by RD, and autonomic functions were compared. Results: RD at a volume of 140 ml suppressed intestinal contractions; the motility index was reduced with RD (P = 0.001). Both EA and TEA ameliorated the suppressed contractions (P = 0.003 and 0.001) and their effects were comparable. RD reduced the percentage of normal intestinal slow waves (P = 0.002) that was increased with both EA and TEA (P = 0.005 and 0.035). No significant difference was noted between EA and TEA. EA and TEA reduced small bowel transit time (P = 0.001 and 0.007); these prokinetic effects were blocked by atropine. Both EA and TEA increased vagal activity assessed by the spectral analysis of heart rate variability (both P = 0.03). Conclusion: RD inhibits postprandial intestinal motility. Both EA and TEA at ST-36 are able to improve the RD-induced impairment in intestinal contractions, transit and slow waves mediated via the vagal mechanism. Needleless TEA is as effective as EA in ameliorating the intestinal hypomotility.