Sethi A K, Sarna S K
Department of Medicine, Medical College of Wisconsin.
Am J Physiol. 1995 Mar;268(3 Pt 1):G530-8. doi: 10.1152/ajpgi.1995.268.3.G530.
We investigated the contractile mechanisms of propulsion in the dog colon. "Propagation index" indicating caudad or orad propagation of contractile states exhibited the strongest correlation with transit during both the fasting and the postprandial states. Other parameters, such as total duration of contractile states and area under contractions, also contributed to transit, but to a lesser degree. All parameters exhibited a stronger correlation with transit during the fasting than during the postprandial state. During the fasting state, the transit rate was faster in the proximal than in the middle colon. The transit rate was linear through the proximal and the middle colon during the postprandial state. In contrast to the phasic contractions and the contractile states, the giant migrating contractions were ultrapropulsive. We conclude that the propagation of contractile states in the colon is a major factor in the slow net distal propulsion of colonic contents. The individual phasic contractions may mainly produce mixing and agitation of colonic contents. Giant migrating contractions rapidly propel colonic contents over long distances.
我们研究了犬结肠推进运动的收缩机制。“传播指数”表明收缩状态的向尾端或向口腔端传播，在禁食和餐后状态下，其与转运的相关性最强。其他参数，如收缩状态的总持续时间和收缩下的面积，也对转运有影响，但程度较小。所有参数在禁食期间与转运的相关性比餐后状态更强。在禁食状态下，近端结肠的转运速率比中段结肠更快。餐后状态下，近端和中段结肠的转运速率呈线性。与阶段性收缩和收缩状态不同，巨大移行性收缩具有超强推进作用。我们得出结论，结肠中收缩状态的传播是结肠内容物缓慢向远端净推进的主要因素。单个阶段性收缩可能主要产生结肠内容物的混合和搅动。巨大移行性收缩可迅速将结肠内容物远距离推进。
