Correlation between chloride flux via the mitochondria-rich cells and transepithelial water movement in isolated frog skin (Rana esculenta).
The coupling between net transepithelial Cl- influx and net water flow was investigated. Experiments were performed on isolated frog skin bathed in isotonic Cl- Ringer's solution in the presence of the Na+ channel blocking agent amiloride in the mucosal solution. The skins were voltage-clamped at -80 or -100 mV (with the serosal solution as reference). Under these conditions the current across the skin is carried by an influx of Cl-. In the absence of antidiuretic hormone the correlation between current and net water flow was low, but in the presence of the antidiuretic hormone, arginine vasotocin, there was a highly significant correlation between current and net water flow. The data presented here indicate that under steady state conditions about 70 molecules of water follow each Cl- ion across the skin. If the water influx is driven by electroosmosis one would expect that a change in current should result in an immediate change in the water flow. There was, however, a considerable time delay between the change in current and water flow. This indicates that the observed coupling between Cl- flux and water flow is caused by current-induced local osmosis and not electroosmosis.
Nielsen
R
R
August Krogh Institute, University of Copenhagen, Denmark.
D000584:Amiloride / Q000494:pharmacology; D000818:Animals; D001834:Body Water / Q000378:metabolism*; D002712:Chlorides / Q000378:metabolism*; D002713:Chlorine; D015232:Dinoprostone / Q000494:pharmacology; D004232:Diuretics / Q000494:pharmacology; D004847:Epithelial Cells; D004848:Epithelium / Q000187:drug effects / Q000378:metabolism; D005110:Extracellular Space / Q000187:drug effects / Q000378:metabolism; D005260:Female; D066298:In Vitro Techniques; D008297:Male; D008928:Mitochondria / Q000378:metabolism*; D009994:Osmolar Concentration; D011868:Radioisotopes; D011893:Rana esculenta; D012867:Skin / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D013806:Theophylline / Q000494:pharmacology; D014665:Vasodilator Agents / Q000494:pharmacology; D014668:Vasotocin / Q000494:pharmacology
D002712:Chlorides; D004232:Diuretics; D011868:Radioisotopes; D014665:Vasodilator Agents; D002713:Chlorine; D000584:Amiloride; D013806:Theophylline; D015232:Dinoprostone; D014668:Vasotocin