Abstract
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.
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Selected References
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- ATKINSON R. M., PARSONS B. J., SMYTH D. H. The intestinal absorption of glucose. J Physiol. 1957 Mar 11;135(3):581–589. doi: 10.1113/jphysiol.1957.sp005732. [DOI] [PMC free article] [PubMed] [Google Scholar]
- COOPERSTEIN I. L., BROCKMAN S. K. The electrical potential difference generated by the large intestine: its relation to electrolyte and water transfer. J Clin Invest. 1959 Feb;38(2):435–442. doi: 10.1172/JCI103818. [DOI] [PMC free article] [PubMed] [Google Scholar]
- COOPERSTEIN I. L., HOGBEN C. A. Ionic transfer across the isolated frog large intestine. J Gen Physiol. 1959 Jan 20;42(3):461–473. doi: 10.1085/jgp.42.3.461. [DOI] [PMC free article] [PubMed] [Google Scholar]
- CURRAN P. F., SOLOMON A. K. Ion and water fluxes in the ileum of rats. J Gen Physiol. 1957 Sep 20;41(1):143–168. doi: 10.1085/jgp.41.1.143. [DOI] [PMC free article] [PubMed] [Google Scholar]
- D'AGOSTINO A., LEADBETTER W. F., SCHWARTZ W. B. Alterations in the ionic composition of isotonic saline solution instilled into the colon. J Clin Invest. 1953 May;32(5):444–448. doi: 10.1172/JCI102757. [DOI] [PMC free article] [PubMed] [Google Scholar]
- HEARON J. Z. The steady state kinetics of some biological systems. Bull Math Biophys. 1949 Jun;11(2):83–95. doi: 10.1007/BF02477495. [DOI] [PubMed] [Google Scholar]
- HOGBEN C. A. Active transport of chloride by isolated frog gastric epithelium; origin of the gastric mucosal potential. Am J Physiol. 1955 Mar;180(3):641–649. [PubMed] [Google Scholar]
- KARNOVSKY M. L., BRUMM A. F. Studies on naturally occurring alpha-glycerol ethers. J Biol Chem. 1955 Oct;216(2):689–701. [PubMed] [Google Scholar]
- McHARDY G. J., PARSONS D. S. The absorption of water and salt from the small intestine of the rat. Q J Exp Physiol Cogn Med Sci. 1957 Jan;42(1):33–48. doi: 10.1113/expphysiol.1957.sp001241. [DOI] [PubMed] [Google Scholar]
- SOLOMON A. K. The permeability of the human erythrocyte to sodium and potassium. J Gen Physiol. 1952 May;36(1):57–110. doi: 10.1085/jgp.36.1.57. [DOI] [PMC free article] [PubMed] [Google Scholar]