The APS Journal Legacy Content is the corpus of 100 years of historical scientific research from the American Physiological Society research journals. This package goes back to the first issue of each of the APS journals including the American Journal of Physiology, first published in 1898. The full text scanned images of the printed pages are easily searchable. Downloads quickly in PDF format.

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The unidirectional fluxes of sodium and chloride across stripped rat colon mucosa were measured and compared with the electrical characteristics of the tissue under voltage-clamped conditions. The relationship between the serosal-mucosal fluxes of the two ions and an imposed potential revealed that the serosal-mucosal flux of sodium was entirely paracellular, whereas there was also a transcellular component of the corresponding chloride flux. In the absence of sodium, the short-circuit current and net chloride flux were abolished; in the absence of chloride, the net sodium flux was reduced but not abolished, and the short-circuit current was unchanged. From an analysis of the effects of the inhibitors, amiloride, theophylline, acetazolamide, furosemide and piretanide, a plausible model was developed to explain the characteristics of these transports. It was proposed that both membranes possess Cl-/HCO-3 antiports, though their sensitivities to inhibitors were different. There is also a Na+/Cl- symport and an electrogenic sodium entry mechanism in the brushborder membrane.

SUMMARY1. A method has been developed to maintain the electrical characteristics of dog colon mucosa stable over prolonged periods in vivo. This was achieved by paying special attention to the constancy of the volume of the organ and its intraluminal pressure during perfusion.2. Intraluminal glucose elicits an increase in transmural potential and short-circuit current; this has been attributed to the presence of a Na-glucose co-transport process in this tissue.3. Na replacement by K in the perfusate caused an increase in the transmural potential, whereas mannitol substitution evoked an inversion. These observations are probably the result of diffusion potentials. In the mannitol solution, glucose effectively abolished the negative transmural potential, whereas in the K solution, the effect of the sugar was smaller than in the control.4. Perfusion of a hyperosmotic solution containing mannitol resulted in the development of streaming potentials across the mucosa. Their magnitude was reduced by addition of 2,4-dinitrophenol or by removal of Na from the perfusate. They were counteracted by replacement of mannitol by glucose. The streaming potentials showed no sign of saturability, reflecting a pronounced hydraulic conductivity of the epithelium.5. The rapidity of onset of the potential response to glucose was enhanced by increasing the perfusion rate, but the response to hyperosmolality was unaffected.6. Streaming potentials, diffusion potentials and glucose-evoked potentials are generally considered to be features of the small intestinal mucosa; their existence in the dog colon indicates that this epithelium has more in common with small gut than with the majority of mammalian colons.