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Characterization of potassium currents modulated by BRL 38227 in rat portal vein. 1992

T Noack, and P Deitmer, and G Edwards, and A H Weston
Department of Physiology, Philipps University, Marburg, Germany.

1. Smooth muscle cells of the rat portal vein were dispersed by enzymatic treatment and recordings of whole-cell membrane potassium currents were made by the voltage-clamp technique. In isolated cells by use of combined voltage- and current-clamp the effect of BRL 38227 on membrane potential and ionic currents was also studied. 2. BRL 38227 (0.1 to 10 microM) induced a non-inactivating potassium current (IKCO) which developed slowly (900 s to 300 s, respectively) to its full size. These effects of BRL 38227 were reversible. 3. In addition to its K-channel opening properties, BRL 38227 (1 to 10 microM) inhibited the amplitude and changed the activation and inactivation characteristics of a slowly-inactivating, calcium influx-independent, outward potassium current (I(TO)). 4. Application of stationary fluctuation analysis to IKCO, showed a mean single channel current of 0.65 pA at -10 mV under a quasi-physiological potassium gradient. 5. In a combined voltage-clamp/current-clamp configuration, BRL 38227 (1 microM) induced a mean hyperpolarization of 22 mV. 6. The induction of IKCO by BRL 38227 and the associated hyperpolarization were suppressed by glibenclamide (1 to 10 microM) in a concentration-dependent manner. Glibenclamide (1 microM) had no effect on the inhibition of I(TO) by BRL 38227 (1 microM).

UI MeSH Term Description Entries
D008297 Male Males
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
D011169 Portal Vein A short thick vein formed by union of the superior mesenteric vein and the splenic vein. Portal Veins,Vein, Portal,Veins, Portal
D011758 Pyrroles Azoles of one NITROGEN and two double bonds that have aromatic chemical properties. Pyrrole
D011919 Rats, Inbred Strains Genetically identical individuals developed from brother and sister matings which have been carried out for twenty or more generations or by parent x offspring matings carried out with certain restrictions. This also includes animals with a long history of closed colony breeding. August Rats,Inbred Rat Strains,Inbred Strain of Rat,Inbred Strain of Rats,Inbred Strains of Rats,Rat, Inbred Strain,August Rat,Inbred Rat Strain,Inbred Strain Rat,Inbred Strain Rats,Inbred Strains Rat,Inbred Strains Rats,Rat Inbred Strain,Rat Inbred Strains,Rat Strain, Inbred,Rat Strains, Inbred,Rat, August,Rat, Inbred Strains,Rats Inbred Strain,Rats Inbred Strains,Rats, August,Rats, Inbred Strain,Strain Rat, Inbred,Strain Rats, Inbred,Strain, Inbred Rat,Strains, Inbred Rat
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.
D005905 Glyburide An antidiabetic sulfonylurea derivative with actions like those of chlorpropamide Glibenclamide,Daonil,Diabeta,Euglucon 5,Euglucon N,Glybenclamide,HB-419,HB-420,Maninil,Micronase,Neogluconin,HB 419,HB 420,HB419,HB420
D000465 Algorithms A procedure consisting of a sequence of algebraic formulas and/or logical steps to calculate or determine a given task. Algorithm
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
D001578 Benzopyrans Compounds with a core of fused benzo-pyran rings. Benzopyran,Chromene,Chromenes

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