CURRAN P F, SCHWARTZ G F
J Gen Physiol. 1960 Jan;43(3):555-71. doi: 10.1085/jgp.43.3.555.
Segments of the colon of anesthetized rats have been perfused in vivo with isotonic NaCl solutions and isotonic mixtures of NaCl and mannitol. Unidirectional and net fluxes of Na and Cl and the net fluxes of water and mannitol have been measured. Net water transport was found to depend directly on the rate of net Na transport. There was no water absorption from these isotonic solutions in the absence of net solute transport, indicating that water transport in the colon is entirely a passive process. At all NaCl concentrations studied, the lumen was found to be electrically negative to the surface of the colon by 5 to 15 mv. Na fluxes both into and out of the lumen were linear functions of NaCl concentration in the lumen. Net Na absorption from lumen to plasma has been observed to take place against an electrochemical potential gradient indicating that Na is actively transported. This active Na transport has been interpreted in terms of a carrier model system. Cl transport has been found to be due almost entirely to passive diffusion.
已在体内用等渗氯化钠溶液以及氯化钠与甘露醇的等渗混合物灌注麻醉大鼠的结肠段。测量了钠和氯的单向通量与净通量以及水和甘露醇的净通量。发现净水转运直接取决于净钠转运速率。在没有净溶质转运的情况下，这些等渗溶液不会发生水吸收，这表明结肠中的水转运完全是一个被动过程。在所研究的所有氯化钠浓度下，发现肠腔相对于结肠表面的电势为负5至15毫伏。钠进出肠腔的通量是肠腔中氯化钠浓度的线性函数。已观察到钠从肠腔到血浆的净吸收是逆着电化学势梯度进行的，这表明钠是被主动转运的。这种主动钠转运已根据载体模型系统进行了解释。已发现氯的转运几乎完全是由于被动扩散。
