Action potentials, afterpotentials, and arrhythmias.
نویسندگان
چکیده
منابع مشابه
Action potentials, afterpotentials, and arrhythmias.
Triggered activity must be added to spontaneous activity and to circus movement as a cause for extrasystoles and tachycardias of either atrial or ventricular origin. The activity of a triggerable focus requires phase 4 depolarization caused by an afterpotential; this distinguishes it from the activity seen in circus movement. A triggerable focus becomes rhythmically active only if driven at a c...
متن کاملAction Potentials, Afterpotentials, and Excitation-Contraction Coupling in Frog Sartorius Fibers without Transverse Tubules
In frog sartorius muscle fibers in which the transverse tubular system has been disrupted by treatment with glycerol, action potentials which are unaccompanied by twitches can be recorded. These action potentials appear to be the same as those recorded in normal fibers except that the early afterpotential usually consists of a small hyperpolarization of short duration. After a train of action p...
متن کاملMiniature potentials, light adaptation and afterpotentials in locust retinula cells.
In dark-adapted retinula cells of the locust, the miniature potentials or bumps have amplitudes of 3-7 mV when recorded in the dark-adapted state with bevelled electrodes at very low light levels. For a sample of N = 378 they had a mean amplitude of 4*55 mV and s.D. 1-59 mV. These are called dark-adapted bumps, and their distribution of amplitudes is presumably a component of the noise of the v...
متن کاملMembrane Potentials and Action Potentials
Electrical potentials exist across the membranes of virtually all cells of the body. In addition, some cells, such as nerve and muscle cells, are capable of generating rapidly changing electrochemical impulses at their membranes, and these impulses are used to transmit signals along the nerve or muscle membranes. In other types of cells, such as glandular cells, macrophages, and ciliated cells,...
متن کاملReperfusion arrhythmias in isolated perfused pig hearts. Inhomogeneities in extracellular potassium, ST and TQ potentials, and transmembrane action potentials.
We recorded direct current electrograms and local [K+]o at multiple sites and transmembrane potentials at selected sites during reperfusion after 5 minutes and 10 minutes of regional ischemia in isolated perfused pig hearts. After 10 minutes of ischemia, the incidence of ventricular fibrillation (VF) was 38%. At 80-90 seconds after reperfusion, [K+]o was 0.8 mM less than in normal tissue in hal...
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ژورنال
عنوان ژورنال: Circulation Research
سال: 1977
ISSN: 0009-7330,1524-4571
DOI: 10.1161/01.res.41.4.415