| Effects of procainamide on automatic and triggered impulse initiation in isolated preparations of canine cardiac Purkinje fibers. | |
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MedLine Citation:
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PMID: 2459539 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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The effects of procainamide (40 mg/L) were studied on automatic and triggered impulse initiation in isolated preparations of canine cardiac Purkinje fibers using standard microelectrode techniques. Procainamide decreased normal automaticity by 48% in Purkinje fibers superfused with standard (KCl 4 mM) Tyrode's solution. In contrast, procainamide decreased the rate of normal Purkinje fibers that had been treated with isoproterenol (1 microM) by only 6% (NS). For comparison, the effects of lidocaine (4 mg/L) and quinidine (5 mg/L) were studied on isoproterenol-treated fibers. Lidocaine and quinidine both significantly decreased the isoproterenol-enhanced rate of normal automaticity (by 45 and 10%, respectively). In studies of the effects of procainamide on Purkinje fibers with abnormal automaticity (i.e., the pacemakers had maximal diastolic potentials less than -60 mV), it was found that drug treatment decreased the rate of 24 h infarct zone Purkinje fibers by 22% and barium chloride (250 microM) treated Purkinje fibers by 51%. In studies of another five infarct zone preparations, the Purkinje fibers had maximal diastolic potentials greater than -75 mV and showed triggered activity with delayed afterdepolarizations. Procainamide decreased the triggered activity in only one of these preparations. Ventricular tachycardias that respond to procainamide may be caused by abnormal automaticity, whereas procainamide refractory tachycardias may result from triggered activity or from catecholamine-enhanced normal automaticity. |
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Authors:
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K H Dangman |
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Publication Detail:
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Type: In Vitro; Journal Article; Research Support, U.S. Gov't, P.H.S. |
Journal Detail:
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Title: Journal of cardiovascular pharmacology Volume: 12 ISSN: 0160-2446 ISO Abbreviation: J. Cardiovasc. Pharmacol. Publication Date: 1988 Jul |
Date Detail:
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Created Date: 1988-11-08 Completed Date: 1988-11-08 Revised Date: 2007-11-14 |
Medline Journal Info:
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Nlm Unique ID: 7902492 Medline TA: J Cardiovasc Pharmacol Country: UNITED STATES |
Other Details:
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Languages: eng Pagination: 78-87 Citation Subset: IM |
Affiliation:
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Department of Pharmacology, College of Physicians and Surgeons of Columbia University, New York, NY 10032. |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Action Potentials
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drug effects Animals Barium / pharmacology Barium Compounds* Chlorides* Dogs Heart Conduction System / drug effects* Isoproterenol / pharmacology Lidocaine / pharmacology Procainamide / pharmacology* Purkinje Fibers / drug effects*, physiology Quinidine / pharmacology |
| Grant Support | |
ID/Acronym/Agency:
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HL-24354/HL/NHLBI NIH HHS |
| Chemical | |
Reg. No./Substance:
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0/Barium Compounds; 0/Chlorides; 10361-37-2/barium chloride; 137-58-6/Lidocaine; 51-06-9/Procainamide; 56-54-2/Quinidine; 7440-39-3/Barium; 7683-59-2/Isoproterenol |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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