Biomaterial Database

Influence of transepithelial potential difference on the sodium uptake at the outer surface of the isolated frog skin. 1973

T U Biber, and M L Sanders

The unidirectional uptake of sodium across the outer surface of the isolated frog skin (J(12) (Na)) was measured in the presence of transepithelial potential difference (Delta(psi)) ranging from +100 to -100 mV. With a sodium concentration of 115 mM in the bathing solutions J(12) (Na) increases significantly when the spontaneous Delta(psi) is reduced to zero by short-circuiting the skin. With an Na concentration of 6 mM a progressive increase J(12) (Na) can be observed when Delta(psi) is decreased in several steps from +100 to -100 mV (serosal side positive and negative, respectively). The observed change J(12) (Na) amounts to a fraction only of that predicted from the shift in Delta(psi). The results suggest that under open circuit conditions the potential step across the outside surface is at most one half of Delta(psi) and that the resistance across the outside and inside barrier of the skin is ohmic. This is in agreement with measurements of intracellular potentials in the frog skin and with resistance measurements carried out in the toad skin. The data strongly support the view that the saturating component of J(psi) proceeds via a charged carrier system. Exposure to negative values of Delta(psi) of 50 mV or more for times of 24 min or more result in a marked reduction of J(12) (Na) which shows only partial or no reversibility.

UI	MeSH Term	Description	Entries
D010042	Ouabain	A cardioactive glycoside consisting of rhamnose and ouabagenin, obtained from the seeds of Strophanthus gratus and other plants of the Apocynaceae; used like DIGITALIS. It is commonly used in cell biological studies as an inhibitor of the NA(+)-K(+)-EXCHANGING ATPASE.	Acocantherin,G-Strophanthin,Acolongifloroside K,G Strophanthin
D010100	Oxygen	An element with atomic symbol O, atomic number 8, and atomic weight [15.99903; 15.99977]. It is the most abundant element on earth and essential for respiration.	Dioxygen,Oxygen-16,Oxygen 16
D011894	Rana pipiens	A highly variable species of the family Ranidae in Canada, the United States and Central America. It is the most widely used Anuran in biomedical research.	Frog, Leopard,Leopard Frog,Lithobates pipiens,Frogs, Leopard,Leopard Frogs
D004594	Electrophysiology	The study of the generation and behavior of electrical charges in living organisms particularly the nervous system and the effects of electricity on living organisms.
D004848	Epithelium	The layers of EPITHELIAL CELLS which cover the inner and outer surfaces of the cutaneous, mucus, and serous tissues and glands of the body.	Mesothelium,Epithelial Tissue,Mesothelial Tissue,Epithelial Tissues,Mesothelial Tissues,Tissue, Epithelial,Tissue, Mesothelial,Tissues, Epithelial,Tissues, Mesothelial
D000584	Amiloride	A pyrazine compound inhibiting SODIUM reabsorption through SODIUM CHANNELS in renal EPITHELIAL CELLS. This inhibition creates a negative potential in the luminal membranes of principal cells, located in the distal convoluted tubule and collecting duct. Negative potential reduces secretion of potassium and hydrogen ions. Amiloride is used in conjunction with DIURETICS to spare POTASSIUM loss. (From Gilman et al., Goodman and Gilman's The Pharmacological Basis of Therapeutics, 9th ed, p705)	Amidal,Amiduret Trom,Amiloberag,Amiloride Hydrochloride,Amiloride Hydrochloride, Anhydrous,Kaluril,Midamor,Midoride,Modamide,Anhydrous Amiloride Hydrochloride,Hydrochloride, Amiloride,Hydrochloride, Anhydrous Amiloride,Trom, Amiduret
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D001001	Anura	An order of the class Amphibia, which includes several families of frogs and toads. They are characterized by well developed hind limbs adapted for jumping, fused head and trunk and webbed toes. The term "toad" is ambiguous and is properly applied only to the family Bufonidae.	Bombina,Frogs and Toads,Salientia,Toad, Fire-Bellied,Toads and Frogs,Anuras,Fire-Bellied Toad,Fire-Bellied Toads,Salientias,Toad, Fire Bellied,Toads, Fire-Bellied
D001693	Biological Transport, Active	The movement of materials across cell membranes and epithelial layers against an electrochemical gradient, requiring the expenditure of metabolic energy.	Active Transport,Uphill Transport,Active Biological Transport,Biologic Transport, Active,Transport, Active Biological,Active Biologic Transport,Transport, Active,Transport, Active Biologic,Transport, Uphill
D012867	Skin	The outer covering of the body that protects it from the environment. It is composed of the DERMIS and the EPIDERMIS.