Diphenylamine-2-carboxylate stimulates sodium ion transport in frog skin epithelium.
1. Diphenylamine-2-carboxylate (DPC), added to the mucosal side of the frog skin, increased reversibly the short-circuit current (I0), even in SO2-(4) Ringer. Amiloride blocked this effect. 2. The maximal stimulation was 140% of the control value and the EC50 was 0.26 mM DPC. 3. The stimulatory effect of DPC was additive to that of oxytocin. 4. The dose-response curves for amiloride determined in the absence and in the presence of 1 mM DPC showed an IC50 of 1.0 microM and 0.8 microM amiloride, respectively. 5. Thus DPC, a blocker of Cl- channels in various Cl-transporting epithelia, exerts a stimulatory effect on the amiloride-sensitive Na+ transport in frog skin.
Durand
J
J
Institute of Physiology, University of Fribourg, Switzerland.
Lehmann
C
C
D000584:Amiloride / Q000494:pharmacology; D000818:Animals; D001692:Biological Transport / Q000187:drug effects; D018118:Chloride Channels; D002712:Chlorides; D004848:Epithelium / Q000187:drug effects / Q000378:metabolism; D008565:Membrane Proteins / Q000037:antagonists & inhibitors; D010121:Oxytocin / Q000494:pharmacology; D011895:Rana ridibunda; D012867:Skin / Q000187:drug effects / Q000378:metabolism*; D012964:Sodium / Q000378:metabolism*; D015222:Sodium Channels / Q000187:drug effects / Q000502:physiology; D062367:ortho-Aminobenzoates / Q000494:pharmacology*
D018118:Chloride Channels; D002712:Chlorides; D008565:Membrane Proteins; D015222:Sodium Channels; D062367:ortho-Aminobenzoates; D010121:Oxytocin; D000584:Amiloride; C001209:fenamic acid; D012964:Sodium