Rosli Reizal M, Heitmann Paul T, Kumar Raghu, Hibberd Tim J, Costa Marcello, Wiklendt Lukasz, Wattchow David A, Arkwright John, de Fontgalland Dayan, Brookes Simon J H, Spencer Nick J, Dinning Phil G
College of Medicine and Public Health & Centre for Neuroscience, Flinders University, Adelaide, SA, Australia.
Departments of Surgery and Gastroenterology, Flinders Medical Centre, Bedford Park, SA, Australia.
Neurogastroenterol Motil. 2020 Oct;32(10):e13871. doi: 10.1111/nmo.13871. Epub 2020 May 6.
Colonic high-resolution manometry (HRM) has been used to reveal discrete, propagating colonic motor patterns. To help determine mechanisms underlying these patterns, we used HRM to record contractile activity in human distal colon ex vivo.
Surgically excised segments of descending (n = 30) or sigmoid colon (n = 4) were immersed in oxygenated Krebs solution at 36°C (n = 34; 16 female; 67.6 ± 12.4 years; length: 24.7 ± 3.5 cm). Contractility was recorded by HRM catheters. After 30 minutes of baseline recording, 0.3 mM lidocaine and/or 1 mM hexamethonium were applied. Ascending neural pathways were activated by electrical field stimulation (EFS; 10 Hz, 0.5 ms, 50 V, 5-s duration) applied to the anal end before and after drug application.
Spontaneous propagating contractions were recorded in all specimens (0.1-1.5 cycles/minute). Most contractions occurred synchronously across all recording sites. In five specimens, rhythmic antegrade contractions propagated across the full length of the preparation. EFS evoked local contractions at the site of stimulation (latency: 5.5 ± 2.4 seconds) with greater amplitude than spontaneous contractions (EFS; 29.3 ± 26.9 vs 12.1 ± 14.8 mm Hg; P = .02). Synchronous or retrograde propagating motor patterns followed EFS; 71% spanned the entire preparation length. Hexamethonium and lidocaine modestly and only temporarily inhibited spontaneous contractions, whereas TTX increased the frequency of contractile activity while inhibiting EFS-evoked contractions.
Our study suggests that the propagated contractions recorded in the organ bath have a myogenic origin which can be regulated by neural input. Once activated at a local site, the contractions do not require the propulsion of fecal content to sustain long-distance propagation.
结肠高分辨率测压法（HRM）已被用于揭示离散的、传播性的结肠运动模式。为了帮助确定这些模式背后的机制，我们使用HRM在离体的人体远端结肠中记录收缩活动。
将手术切除的降结肠段（n = 30）或乙状结肠段（n = 4）浸入36°C的含氧 Krebs 溶液中（n = 34；16名女性；67.6 ± 12.4岁；长度：24.7 ± 3.5 cm）。通过HRM导管记录收缩性。在基线记录30分钟后，应用0.3 mM利多卡因和/或1 mM六甲铵。在给药前后，通过施加于肛门端的电场刺激（EFS；10 Hz，0.5 ms，50 V，持续5秒）激活上行神经通路。
在所有标本中均记录到自发传播性收缩（0.1 - 1.5次/分钟）。大多数收缩在所有记录部位同步发生。在五个标本中，有节律的顺行收缩在整个标本长度上传播。EFS在刺激部位诱发局部收缩（潜伏期：5.5 ± 2.4秒），其幅度大于自发收缩（EFS；29.3 ± 26.9 vs 12.1 ± 14.8 mmHg；P = 0.02）。EFS后出现同步或逆行传播的运动模式；71%跨越整个标本长度。六甲铵和利多卡因仅适度且暂时抑制自发收缩，而TTX增加收缩活动频率，同时抑制EFS诱发的收缩。
我们的研究表明，在器官浴中记录到的传播性收缩具有肌源性起源，可受神经输入调节。一旦在局部部位被激活，收缩不需要粪便内容物的推进来维持远距离传播。
