title: K+-permeability of the outer border of the frog skin (R. temporaria).
abstract: Skins from Rana temporaria, investigated with microelectrode techniques in the absence of Na uptake across the outer border (Na-free epithelial solution or amiloride), were found to be permeable to K+ at the apical membrane in 10-20% of the experiments. Full development of the K+-permeable state requires the absence of Na+ uptake for certain periods of time, which suggests that the K+-permeability of the apical membrane is higher at lower intracellular [Na]. The addition of Ba++ reduces the K+-permeability of the apical membrane. These skins may provide a model for the study of transcellular K+ movements.
mesh_terms: D000584:Amiloride / Q000494:pharmacology; D000818:Animals; D001001:Anura; D001464:Barium / Q000494:pharmacology; D001692:Biological Transport; D066298:In Vitro Techniques; D008564:Membrane Potentials; D008566:Membranes / Q000378:metabolism; D008839:Microelectrodes; D010539:Permeability; D011188:Potassium / Q000378:metabolism*; D011896:Rana temporaria; D012867:Skin / Q000378:metabolism*; D012964:Sodium / Q000378:metabolism
chemical_list: D001464:Barium; D000584:Amiloride; D012964:Sodium; D011188:Potassium