Jodal M, Hallbäck D A, Lundgren O
Acta Physiol Scand. 1978 Jan;102(1):94-107. doi: 10.1111/j.1748-1716.1978.tb06049.x.
A cryoscoptic technique has been developed that makes it possible to determine tissue osmolality in the core of the intestinal villi. During absorption from an isotonic electrolyte solution containing glucose an osmolality gradient was demonstrated from tip to base of the villi in both the jejunum and the ileum. The tissue osmolality at the villous tips was measured to 1 000-1 200 mOsm/kg H2O while the osmolality at the villous base was approximately isotonic with plasma. Increasing intestinal blood flow by i.a. administration of a vasodilator drug, or making the intestine ischemic by clamping the intestinal vascular supply while supplying the mucosa with oxygen, markedly decreased tissue osmolality. Substituting all sodium ions with choline in the luminal perfusate abolished almost completely the tissue hyperosmolality and the intestine became a secretory organ. These observations are consistent with the view that the observed villous tissue hyperosmolality was created by a countercurrent multiplication of sodium chloride. The physiological implications of this mechanism is discussed and it is, among other things, proposed that the hyperosmolar region represents the hyperosmotic compartment necessary for explaining intestinal water absorption.
已经开发出一种冰点测定技术，该技术能够测定肠绒毛核心部位的组织渗透压。在从含有葡萄糖的等渗电解质溶液中吸收的过程中，空肠和回肠的绒毛从顶端到基部均显示出渗透压梯度。测得绒毛顶端的组织渗透压为1000 - 1200 mOsm/kg H₂O，而绒毛基部的渗透压与血浆近似等渗。通过腹腔内注射血管扩张剂药物增加肠血流量，或者在向黏膜供应氧气的同时钳夹肠血管供应使肠缺血，均会显著降低组织渗透压。用胆碱替代管腔内灌流液中的所有钠离子几乎完全消除了组织高渗现象，并且肠变成了一个分泌器官。这些观察结果与以下观点一致，即观察到的绒毛组织高渗是由氯化钠的逆流倍增作用产生的。本文讨论了该机制的生理意义，其中特别提出，高渗区域代表了解释肠道水吸收所需的高渗区室。
