Block of sodium current by heptanol in voltage-clamped canine cardiac Purkinje cells.
نویسندگان
چکیده
منابع مشابه
Extracellular [K+] fluctuations in voltage-clamped canine cardiac Purkinje fibers.
Membrane currents and extracellular [K+] were measured in canine Purkinje strands during voltage-clamp steps to plateau or diastolic potentials. Extracellular [K+] increased during step depolarizations and decreased during step hyperpolarizations. On hyperpolarization, the largest fraction of the K+ depletion occurred during the initial 500 ms of the voltage-clamp step and was correlated with a...
متن کاملMembrane current following activity in canine cardiac Purkinje fibers
Membrane current following prolonged periods of rapid stimulation was examined in short (less than 1.5 mm) canine cardiac Purkinje fibers of radius less than 0.15 mm. The Purkinje fibers were repetitively stimulated by delivering trains of depolarizing voltage clamp pulses at rapid frequencies. The slowly decaying outward current following repetitive stimulation ("post-drive" current) is elimin...
متن کاملVoltage-dependent block of calcium channel current in the calf cardiac Purkinje fiber by dihydropyridine calcium channel antagonists.
We have investigated the mechanisms of blockade of calcium channel current by the dihydropyridines, e.g. nisoldipine, nitrendipine, and nicardipine. Membrane current was recorded in isolated calf Purkinje fibers using a two-microelectrode voltage-clamp technique, and voltage protocols were designed to identify voltage- and use-dependent block by these compounds systematically. Our results show ...
متن کاملKinetic analysis of single sodium channels from canine cardiac Purkinje cells
Single sodium channel events were recorded from cell-attached patches on single canine cardiac Purkinje cells at 10-13 degrees C. Data from four patches containing two to four channels and one patch with one channel were selected for quantitative analysis. The channels showed prominent reopening behavior at voltages near threshold, and the number of reopenings declined steeply with depolarizati...
متن کاملBarbiturates Block Sodium and Potassium Conductance Increases in Voltage-Clamped Lobster Axons
Sodium pentobarbital and sodium thiopental decrease both the peak initial (Na) and late steady-state (K) currents and reduce the maximum sodium and potassium conductance increases in voltage-clamped lobster giant axons. These barbiturates also slow the rate at which the sodium conductance turns on, and shift the normalized sodium conductance vs. voltage curves in the direction of depolarization...
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ژورنال
عنوان ژورنال: Circulation Research
سال: 1991
ISSN: 0009-7330,1524-4571
DOI: 10.1161/01.res.68.4.977