Biomaterial Database

Effect of prolonged saline-exposure on sodium transport across frog skin. 1969

R Hornby, and S Thomas

1. Differences in Na transport between skins from Rana temporaria and R. esculenta maintained for up to several weeks in water or 0.7% saline (0.7 g NaCl in 100 ml. H(2)O), with and without daily injections of 4% saline (4 g NaCl in 100 ml. H(2)O), were measured, in vitro.2. In saline-treated skins, the following changes were found:(a) An increased Na content.(b) A consistent decrease in short-circuit current (I(sc)).(c) An increased d.c. resistance, R, the consistency of which varied with the anion content of the Ringer solution.(d) A highly significant fall in Na influx, accounting for the reduced I(sc); a small reduction in Na efflux was not significant, statistically.(e) The Pitressin-induced increment in I(sc) was usually considerably lower compared with that in water-exposed skins; considered relative to the pre-Pitressin values, however, there were no clear differences.(f) By calculation from the changes in resistance (R) caused by replacement of outer Na(2)SO(4) Ringer by K(2)SO(4) Ringer solution,I. E(0), the electromotive force of the active sodium transport system, was moderately, but significantly, reduced,II. R(shunt), the shunt path resistance, was moderately, but significantly, increased, andIII. R(ser), the series path resistance, was considerably, and highly significantly, increased.(g) K influx from outer K(2)SO(4) Ringer solution was reduced.3. Differences between skins from water-exposed and saline-treated frogs persisted, in vitro, despite the occurrence of anionic-dependent acute changes after mounting in Ringer solution.4. There were seasonal changes in I(sc), and in the effects of saline treatment.5. The findings are discussed in terms of decreased permeability of outer barriers to ion-diffusion, and reduced activity of a Na pump.

UI	MeSH Term	Description	Entries
D008564	Membrane Potentials	The voltage differences across a membrane. For cellular membranes they are computed by subtracting the voltage measured outside the membrane from the voltage measured inside the membrane. They result from differences of inside versus outside concentration of potassium, sodium, chloride, and other ions across cells' or ORGANELLES membranes. For excitable cells, the resting membrane potentials range between -30 and -100 millivolts. Physical, chemical, or electrical stimuli can make a membrane potential more negative (hyperpolarization), or less negative (depolarization).	Resting Potentials,Transmembrane Potentials,Delta Psi,Resting Membrane Potential,Transmembrane Electrical Potential Difference,Transmembrane Potential Difference,Difference, Transmembrane Potential,Differences, Transmembrane Potential,Membrane Potential,Membrane Potential, Resting,Membrane Potentials, Resting,Potential Difference, Transmembrane,Potential Differences, Transmembrane,Potential, Membrane,Potential, Resting,Potential, Transmembrane,Potentials, Membrane,Potentials, Resting,Potentials, Transmembrane,Resting Membrane Potentials,Resting Potential,Transmembrane Potential,Transmembrane Potential Differences
D002463	Cell Membrane Permeability	A quality of cell membranes which permits the passage of solvents and solutes into and out of cells.	Permeability, Cell Membrane
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.
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
D012621	Seasons	Divisions of the year according to some regularly recurrent phenomena usually astronomical or climatic. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)	Seasonal Variation,Season,Seasonal Variations,Variation, Seasonal,Variations, Seasonal
D012867	Skin	The outer covering of the body that protects it from the environment. It is composed of the DERMIS and the EPIDERMIS.
D012964	Sodium	A member of the alkali group of metals. It has the atomic symbol Na, atomic number 11, and atomic weight 23.	Sodium Ion Level,Sodium-23,Ion Level, Sodium,Level, Sodium Ion,Sodium 23
D012965	Sodium Chloride	A ubiquitous sodium salt that is commonly used to season food.	Sodium Chloride, (22)Na,Sodium Chloride, (24)NaCl