Amphotericin B enhanced anomalous potential difference response to changes in aqueous K+ in frog cornea.
An increase in aqueous K+ from 0 to 4 mM increased the potential difference (anomalous response of electrogenic (Na+ + K+)-ATPase antiport) by 1.1 mV in Cl(-)-free solutions compared to 6.8 mV in Cl- solutions. With amphotericin B added to the tear solution in Cl(-)-free solutions, the anomalous PD response for the addition of 4 mM K+ to the aqueous solution was about 20 mV, significantly greater than in Cl- solutions. This anomalous response was inhibited by ouabain. These data support the electrogenicity of the (Na+ + K+)-ATPase pump. It is also evident that, for the pump to respond, Na+ should readily enter the cell. This may be accomplished experimentally, either across the basolateral membrane in Cl- solutions or across the apical membrane in Cl(-)-free solutions with amphotericin B present in the tear solution.
D000666:Amphotericin B / Q000494:pharmacology*; D000818:Animals; D002712:Chlorides / Q000502:physiology; D003315:Cornea / Q000187:drug effects / Q000378:metabolism* / Q000502:physiology; D066298:In Vitro Techniques; D008564:Membrane Potentials; D010042:Ouabain / Q000494:pharmacology; D011188:Potassium / Q000378:metabolism*; D011892:Rana catesbeiana; D012964:Sodium / Q000378:metabolism; D000254:Sodium-Potassium-Exchanging ATPase / Q000032:analysis
D002712:Chlorides; D010042:Ouabain; D000666:Amphotericin B; D012964:Sodium; D000254:Sodium-Potassium-Exchanging ATPase; D011188:Potassium