Huge A, Weber E, Ehrlein H J
Institute of Zoophysiology, University of Hohenheim, Stuttgart, Germany.
Dig Dis Sci. 1995 May;40(5):1024-34. doi: 10.1007/BF02064192.
We wanted to clarify whether the postprandial intestinal feedback control activated by nutrients in the distal gut exerts different effects on motility, transit of digesta, and absorption of nutrients in the proximal gut. Additionally, interrelationships among motility, transit, and absorption were to be elucidated because these relationships have only been investigated in the fasted state. In five minipigs, a 150-cm segment of the proximal jejunum was isolated by two cannulas. Motility of the jejunal segment was recorded by multiple strain gauges and analyzed by computerized methods. Markers (Cr- and Cu-EDTA) were used for the measurement of the flow rate, transit time, and absorption of nutrients. After a meal, the test segment was perfused with 2 kcal/min of an elemental diet over a period of 90 min. A feedback inhibition was activated by infusion of nutrients into the midgut at rates of 1-4 kcal/min. Saline was infused as control. With increasing energy loads infused into the midgut, the motility index and the length of contraction waves decreased, whereas the incidence of stationary contractions increased, ie, the motility changed from a propulsive to a segmenting pattern. These modulations of motility were associated with a linear decrease in the flow rate and a linear increase in transit time. Flow and transit were linearly correlated with each other. Additionally, the reduction in flow rate and the delay in luminal transit were associated with a linear increase in the absorption of nutrients. However, the increase in absorption induced by the feedback mechanism was small (7.3-13.4%) compared to the marked inhibition of the motility parameters (54-64%), the flow rate (59%), and the delay of transit (5.8-fold). Feedback control primarily modulated motor patterns and luminal flow, whereas the small increase in absorption was only a side effect due to the longer contact time of the nutrients with the mucosa.
我们想要阐明，由远端肠道中的营养物质激活的餐后肠道反馈控制，是否会对近端肠道的运动、食糜转运及营养物质吸收产生不同影响。此外，由于仅在禁食状态下研究过运动、转运和吸收之间的相互关系，因此需要对这些关系进行阐明。在5头小型猪中，通过两个套管分离出一段150厘米长的近端空肠。通过多个应变片记录空肠段的运动，并采用计算机方法进行分析。使用标记物（铬和铜的乙二胺四乙酸盐）来测量营养物质的流速、转运时间和吸收情况。进食后，在90分钟内以每分钟2千卡的速率向测试段灌注要素饮食。通过以每分钟1 - 4千卡的速率向中肠注入营养物质来激活反馈抑制。注入生理盐水作为对照。随着注入中肠的能量负荷增加，运动指数和收缩波长度减小，而静止收缩的发生率增加，即运动从推进模式转变为分段模式。这些运动的调节与流速的线性降低和转运时间的线性增加相关。流速和转运呈线性相关。此外，流速降低和管腔内转运延迟与营养物质吸收的线性增加相关。然而，与运动参数（54 - 64%）、流速（59%）和转运延迟（5.8倍）的显著抑制相比，反馈机制引起的吸收增加较小（7.3 - 13.4%）。反馈控制主要调节运动模式和管腔内流动，而吸收的小幅增加只是由于营养物质与黏膜接触时间延长而产生的副作用。
