Biomaterial Database

The effect of external potassium on the blockade of the inward-going rectification by cesium ions in the frog atrial trabeculae. 1982

A Taupignon, and M Sauvignon, and J Lenfant

The effect of Cs ions on the inward-going rectification of the frog atrial trabeculae was investigated in various external K concentrations using the double sucrose gap technique. In the presence of 10 mM Cs the inward-going rectification disappeared and the steady-state background current was related linearly to the membrane potential. The Cs-sensitive current was obtained by the difference between control and membrane currents measured in the presence of Cs ions. The current rectified in the inward direction and its reversal potential was very close to the K equilibrium potential. At potentials positive to the resting value the effect of Cs was progressively reduced, leaving the outward rectifier component of the background current unaffected. The analysis of the conductances calculated from the current-voltage relationships showed that the Cs effect was insensitive to moderate changes in the external K concentration, indicating that Cs ions strongly reduced K conductance. In the presence of high K concentrations the blocking effect of Cs appeared to be diminished. The lack of Cs action on the outward rectifier component and the results obtained in high K solutions were discussed.

UI	MeSH Term	Description	Entries
D007473	Ion Channels	Gated, ion-selective glycoproteins that traverse membranes. The stimulus for ION CHANNEL GATING can be due to a variety of stimuli such as LIGANDS, a TRANSMEMBRANE POTENTIAL DIFFERENCE, mechanical deformation or through INTRACELLULAR SIGNALING PEPTIDES AND PROTEINS.	Membrane Channels,Ion Channel,Ionic Channel,Ionic Channels,Membrane Channel,Channel, Ion,Channel, Ionic,Channel, Membrane,Channels, Ion,Channels, Ionic,Channels, Membrane
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
D011188	Potassium	An element in the alkali group of metals with an atomic symbol K, atomic number 19, and atomic weight 39.10. It is the chief cation in the intracellular fluid of muscle and other cells. Potassium ion is a strong electrolyte that plays a significant role in the regulation of fluid volume and maintenance of the WATER-ELECTROLYTE BALANCE.
D011690	Purkinje Fibers	Modified cardiac muscle fibers composing the terminal portion of the heart conduction system.	Purkinje Fiber,Fiber, Purkinje,Fibers, Purkinje
D011893	Rana esculenta	An edible species of the family Ranidae, occurring in Europe and used extensively in biomedical research. Commonly referred to as "edible frog".	Pelophylax esculentus
D002462	Cell Membrane	The lipid- and protein-containing, selectively permeable membrane that surrounds the cytoplasm in prokaryotic and eukaryotic cells.	Plasma Membrane,Cytoplasmic Membrane,Cell Membranes,Cytoplasmic Membranes,Membrane, Cell,Membrane, Cytoplasmic,Membrane, Plasma,Membranes, Cell,Membranes, Cytoplasmic,Membranes, Plasma,Plasma Membranes
D002586	Cesium	A member of the alkali metals. It has an atomic symbol Cs, atomic number 55, and atomic weight 132.91. Cesium has many industrial applications, including the construction of atomic clocks based on its atomic vibrational frequency.	Caesium,Caesium-133,Cesium-133,Caesium 133,Cesium 133
D004553	Electric Conductivity	The ability of a substrate to allow the passage of ELECTRONS.	Electrical Conductivity,Conductivity, Electric,Conductivity, Electrical
D006321	Heart	The hollow, muscular organ that maintains the circulation of the blood.	Hearts
D006325	Heart Atria	The chambers of the heart, to which the BLOOD returns from the circulation.	Heart Atrium,Left Atrium,Right Atrium,Atria, Heart,Atrium, Heart,Atrium, Left,Atrium, Right