Chen Jie, Song Geng-Qing, Yin Jieyun, Koothan Thillai, Chen J D Z
Division of Gastroenterology, University of Texas Medical Branch, Galveston, TX 77555-0632, USA.
Am J Physiol Gastrointest Liver Physiol. 2008 Sep;295(3):G614-20. doi: 10.1152/ajpgi.90322.2008. Epub 2008 Jul 24.
Rectal distension (RD) is known to induce upper gastrointestinal (GI) symptoms. The aim of this study was to investigate the effects and underlying mechanisms of RD on gastric slow waves (GSW) and motor activity and furthermore to investigate the effects and mechanisms of electroacupuncture (EA) on GSW and motor activity. Eight female hound dogs chronically implanted with gastric serosal electrodes and a gastric fistula were studied in six separate sessions. Antral motility, GSW, heart rate variability, and rectal pressure were evaluated for the above purposes. 1) RD at a volume of 120 ml suppressed antral motility significantly. Guanethidine blocked the inhibitory effect of RD. EA at ST36 was able to restore the suppressed antral contractions induced by RD (16.6+/-1.7 vs. 8.0+/-1.4, P<0.001). Naloxone partially blocked the effect of EA on antral contractions. 2) RD reduced the percentage of normal GSW from 98.8+/-0.8% at baseline to 76.1+/-8.6% (P<0.05) that was increased to 91.8+/-3.0% with EA. The effects of EA on the GSW were nullified by the presence of naloxone. 3) EA did not show any significant effect on rectal pressure, suggesting that the ameliorating effects of EA on RD-induced impaired gastric motility were not due to a decrease in rectal pressure. 4) EA increased the vagal activity suppressed by RD. In conclusion, RD inhibits postprandial gastric motility and impairs GSW in dogs, and the inhibitory effects are mediated via the adrenergic pathways. EA at ST36 is able to restore the RD-induced impaired GSW and motor activities, possibly by enhancing vagal activity, and is partially mediated via the opioid pathway. EA may have therapeutic potential for functional gastrointestinal disorders.
直肠扩张（RD）已知会诱发上消化道（GI）症状。本研究旨在探讨RD对胃慢波（GSW）和运动活性的影响及潜在机制，进而研究电针（EA）对GSW和运动活性的影响及机制。对8只长期植入胃浆膜电极和胃瘘的雌性猎犬进行了6次单独实验。为实现上述目的，评估了胃窦运动、GSW、心率变异性和直肠压力。1）120毫升容量的RD显著抑制胃窦运动。胍乙啶可阻断RD的抑制作用。针刺足三里能恢复由RD引起的被抑制的胃窦收缩（16.6±1.7对8.0±1.4，P<0.001）。纳洛酮部分阻断了电针对胃窦收缩的作用。2）RD使正常GSW的百分比从基线时的98.8±0.8%降至76.1±8.6%（P<0.05），而电针可使其升至91.8±3.0%。纳洛酮的存在使电针对GSW的作用无效。3）电针未对直肠压力产生显著影响，这表明电针改善RD诱导的胃动力受损的作用并非源于直肠压力的降低。4）电针增加了被RD抑制的迷走神经活性。总之，RD抑制犬餐后胃动力并损害GSW，且抑制作用通过肾上腺素能途径介导。针刺足三里能够恢复RD诱导的受损GSW和运动活性，可能是通过增强迷走神经活性，且部分通过阿片样物质途径介导。电针可能对功能性胃肠疾病具有治疗潜力。
