RELATIONSHIP BETWEEN DISTENSION AND ABSORPTION IN RAT INTESTINE .2. EFFECTS OF VOLUME AND FLOW-RATE ON TRANSPORT
RELATIONSHIP BETWEEN DISTENSION AND ABSORPTION IN RAT INTESTINE .2. EFFECTS OF VOLUME AND FLOW-RATE ON TRANSPORT
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DOI：
10.1016/0016-5085(88)90009-1
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发表时间：
1988-05-01
期刊：
影响因子：
29.4
通讯作者：
KENNEDY, JG
中科院分区：
文献类型：
--
作者：
HARRIS, MS;KENNEDY, JG
在完整动物中的研究表明，肠溶质吸收可能会随着管腔内体积和流速的增加而增强，这可能是因为功能性吸收表面积的增加或未搅拌层的扰动。我们使用单通灌注大鼠回肠，同时进行输注和撤回以相等的速度，以确定在3.0和12.5厘米水柱之间的压力溶质吸收的体积和流速的单独影响。膨胀增强了被动探针（3 H2O，尿素）的吸收，没有影响的溶质运输的载体机制（D-葡萄糖，L-丙氨酸）的吸收，并导致减少钠和水的净吸收时，腔内压力超过10厘米水柱。增加流速可促进葡萄糖和3 H2O的吸收。然而，增加流速和扩张对3 H2O的影响不是相加的。在存在更高充盈体积的情况下，更快的流速不会导致3 H2O吸收进一步增加;反之亦然，在更快的流速下，当管腔体积增加时，不会观察到3 H2O吸收进一步增加。我们的结论是，增加管腔内体积增强了被动转运的溶质的吸收，但不是载体介导的机制，可能是通过增加功能性吸收表面积。增加的流速和体积可以部分地通过类似的机制增加被动吸收的探针的吸收。
Studies in intact animals have shown that intestinal solute absorption may be enhanced with increasing intraluminal volume and flow rate, perhaps because of increases in functional absorptive surface area or perturbation of unstirred layers. We used single-pass perfusions of rat ileum, performed by simultaneously infusing and withdrawing at equal rates, to determine the separate effects of volume and flow rate on solute absorption at pressures between 3.0 and 12.5 cmH2O. Distention enhanced the absorption of passive probes (3H2O, urea), had no effect on the absorption of solutes transported by carrier mechanisms (D-glucose, L-alanine), and led to decreases in the net absorption of sodium and water whenever intraluminal pressure exceeded 10 cmH2O. Increasing flow rate enhanced the absorption of both glucose and 3H2O. However, the effects of increasing flow rate and distention on 3H2O were not additive. In the presence of higher filling volume, faster flow rate led to no further increases in 3H2O absorption; vice versa, at faster flow rate, no further increases in 3H2O absorption were noted when luminal volume was increased. We conclude that increased intraluminal volume enhances the absorption of solutes transported by passive but not carrier-mediated mechanisms, perhaps via augmentation of functional absorptive surface area. Increased flow rate and volume may increase the absorption of passively absorbed probes, in part, by a similar mechanism.