| Effects of Tityus serrulatus scorpion venom and one of its purified toxins (toxin gamma) on the isolated guinea-pig heart. | |
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MedLine Citation:
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PMID: 1676949 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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1. The effects of Tityus serrulatus scorpion venom and its most important toxin (toxin gamma) were investigated on isolated guinea-pig hearts, perfused with Locke solution, by the Langendorff's method. 2. The cardiac contraction, the coronary flow and the electrocardiogram (ECG) were simultaneously recorded. 3. Bolus injections of 25, 50 or 100 micrograms of scorpion venom and 2.5, 5 or 10 micrograms of toxin gamma in the heart evoked complex effects which were divided into 3 phases: an initial phase (tachycardia or bradycardia associated with an increase in contractile force), an intermediate phase (oscillations of cardiac rate, contractile force and coronary flow, due to wandering pacemakers) and a third phase (sinus tachycardia). 4. The bradycardia and the oscillations of rhythm were prevented by atropine, whereas the tachycardia and the increase in contractile force were prevented either by reserpine or propranolol. 5. Scorpion venom or toxin gamma induced a ST segment displacement in the ECG, explained by a transitory myocardial hypoxia, due to an increase in the contractile force and a simultaneous decrease of the coronary flow. 6. Perfusion of the heart with Locke solution containing 2% scorpion antivenom prevented almost totally the effects elicited by the venom. 7. It is concluded that the complex effects induced by scorpion venom and toxin gamma are due to the simultaneous release of acetylcholine and catecholamines from postganglionic nerve fibers in the heart. |
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Authors:
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N P Silveira; T Moraes-Santos; A D Azevedo; L Freire-Maia |
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Publication Detail:
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Type: Comparative Study; Journal Article; Research Support, Non-U.S. Gov't |
Journal Detail:
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Title: Comparative biochemistry and physiology. C, Comparative pharmacology and toxicology Volume: 98 ISSN: 0742-8413 ISO Abbreviation: Comp. Biochem. Physiol. C, Comp. Pharmacol. Toxicol. Publication Date: 1991 |
Date Detail:
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Created Date: 1991-08-21 Completed Date: 1991-08-21 Revised Date: 2007-07-23 |
Medline Journal Info:
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Nlm Unique ID: 8310013 Medline TA: Comp Biochem Physiol C Country: ENGLAND |
Other Details:
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Languages: eng Pagination: 329-36 Citation Subset: IM |
Affiliation:
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Departamento de Fisiologia e Biofisica, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brasil. |
Export Citation:
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| MeSH Terms | |
Descriptor/Qualifier:
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Animals Antivenins / pharmacology Atropine / pharmacology Coronary Vessels / drug effects Electrocardiography / drug effects Female Guinea Pigs Heart / drug effects* Heart Rate / drug effects Male Myocardial Contraction / drug effects Propranolol / pharmacology Scorpion Venoms / toxicity* |
| Chemical | |
Reg. No./Substance:
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0/Antivenins; 0/Scorpion Venoms; 51-55-8/Atropine; 525-66-6/Propranolol |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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