Kvietys P R, Barrowman J A, Harper S L, Granger D N
Am J Physiol. 1986 Jul;251(1 Pt 1):G25-33. doi: 10.1152/ajpgi.1986.251.1.G25.
Blood flow, arteriovenous O2 difference, and lumen pressure were measured in isolated loops of canine ileum. Ileal pressure was increased by an intra-arterial infusion of either Met-enkephalin or acetylcholine. Pressures were quantitated using a motility index (MI = mean of the pressure peaks divided by number of contractions per minute). Both Met-enkephalin and acetylcholine increased MI in a dose-dependent fashion. The highest MI achieved with acetylcholine was 37.9 mmHg, while Met-enkephalin produced a maximal MI of 8.1 mmHg. Ileal oxygen uptake increased when MI reached values greater than 6. There was a direct linear relationship between oxygen uptake and MI. Distension of the lumen in the absence of motility resulted in a decrease in oxygen uptake when lumen pressure reached 15-20 mmHg. The results of these studies indicate that contractions of intestinal smooth muscle can increase intestinal oxygen uptake and may contribute to the overall oxygen demands of the gut under conditions of fasting and feeding. Furthermore, large (greater than 20 mmHg) increments in lumen pressure during enhanced motility may compromise intestinal oxygenation.
在犬回肠的离体肠袢中测量了血流量、动静脉氧分压差和管腔压力。通过动脉内输注甲硫氨酸脑啡肽或乙酰胆碱来升高回肠压力。使用运动指数（MI = 压力峰值平均值除以每分钟收缩次数）对压力进行定量。甲硫氨酸脑啡肽和乙酰胆碱均以剂量依赖性方式增加MI。乙酰胆碱达到的最高MI为37.9 mmHg，而甲硫氨酸脑啡肽产生的最大MI为8.1 mmHg。当MI达到大于6的值时，回肠摄氧量增加。摄氧量与MI之间存在直接的线性关系。在无运动的情况下，当管腔压力达到15 - 20 mmHg时，管腔扩张导致摄氧量减少。这些研究结果表明，肠道平滑肌收缩可增加肠道摄氧量，并可能在禁食和进食状态下对肠道的整体氧需求有贡献。此外，在运动增强期间管腔压力大幅升高（大于20 mmHg）可能会损害肠道氧合。
