Mechanism of isotonic water transport in glands
- 1 July 1989
- journal article
- research article
- Published by Wiley in Acta Physiologica Scandinavica
- Vol. 136 (3), 443-454
- https://doi.org/10.1111/j.1748-1716.1989.tb08686.x
Abstract
Since water and electrolytes pass cell membranes via separate channels, there can be no interactions in the membranes, and osmotic interactions between water and solutes can be expressed as the product of solute flux, frictional coefficient of solute, and length of pathway. It becomes clear that isotonic transport via a cell is impossible. In glands, where cation-selective junctions impede anion flux between the cells, isotonic water transport is only possible if sodium, after having passed the junction, is reabsorbed in the acinus and returned tot he serodal side. Thus it can be recycled via the cation-selective junction and exert its drag on water more than once. This hypothesis was tested on frog skin glands. Na channels of the principal cells were closed with amiloride in the outside solution, and secretion stimulated with noradrenaline in the inside solution. Influx and efflux of Na, K and Br (used as tracer for Cl) were measured on paired half-skins during the constant-secretion phase. Flux ratios for both Na and K were higher than expected for electrodiffusion, indicating outgoing solvent drag. Flux ratios for K were much higher than those for Na. This is in agreement with the concept that Na is reabsorbed in the acinus and K is not. Two independent expressions for the degree of sodium recycling are developed. Under all experimental conditions these expressions give values for the recycling which are in good agreement.Keywords
This publication has 14 references indexed in Scilit:
- Membrane mechanisms in volume and pH regulation in vertebrate cellsPhysiological Reviews, 1989
- Prostaglandin E2-stimulated glandular ion and water secretion in isolated frog skin (Rana esculenta)The Journal of Membrane Biology, 1987
- Presence of a sodium-potassium chloride cotransport system in the rectal gland ofSqualus acanthiasThe Journal of Membrane Biology, 1983
- Exchange diffusion, electrodiffusion and rectification in the chloride transport pathway of frog skinThe Journal of Membrane Biology, 1983
- Relation between chloride exchange diffusion and a conductive chloride pathway across the isolated skin of the toad (Bufo bufo)Acta Physiologica Scandinavica, 1978
- TRANSPORTING EPITHELIAPublished by Elsevier ,1972
- β-Adrenergic stimulation of frog skin mucous glands: Non-specific inhibition by adrenergic blocking agentsComparative and General Pharmacology, 1971
- The Contributions of Diffusion and Flow to the Passage of D2O through Living Membranes.: Effect of Neurohypophysenl Hormone 011 Isolated Anuran Skin.Acta Physiologica Scandinavica, 1953
- The Origin of the Short‐circuit Current in the Adrenaline Stimulated Frog Skin.Acta Physiologica Scandinavica, 1953
- Some Aspects of the Application of Tracers in Permeability StudiesPublished by Wiley ,1952