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Cardiotoxins from Cobra Naja oxiana Change the Force of Contraction and the Character of Rhythmoinotropic Phenomena in the Rat Myocardium
The study of the influence of cobra Naja oxiana cardiotoxins on the contractility of the rat papillary muscles and its rhythmoinotropic characteristics has shown that the presence of toxins induces a slight contractility decrease in the stimulation frequency range up to 0.1 Hz. In the stimulation fr...
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Published in: | Doklady. Biochemistry and biophysics 2019-07, Vol.487 (1), p.282-286 |
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Main Authors: | , , , , |
Format: | Article |
Language: | English |
Subjects: | |
Citations: | Items that this one cites Items that cite this one |
Online Access: | Get full text |
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Summary: | The study of the influence of cobra
Naja oxiana
cardiotoxins on the contractility of the rat papillary muscles and its rhythmoinotropic characteristics has shown that the presence of toxins induces a slight contractility decrease in the stimulation frequency range up to 0.1 Hz. In the stimulation frequency range from 0.1 to 0.5 Hz, a positive inotropic effect is found. However, the positive inotropic effect is replaced by a negative one with further increase in the frequency up to 3 Hz. In the presence of cardiotoxins, the positive force–frequency relationship in the region of 1–3 Hz, characteristic of healthy rat myocardium, disappears and the relationship becomes completely negative. L-type calcium channel blocker nifedipine does not affect the changes induced by toxins, while a high concentration (10 mM) of calcium prevents the effects of cardiotoxins on the muscle. The results obtained show that the impairment of the force–frequency relationship occurs long before the development of irreversible damage in the myocardium and may be the first sign of the pathological action of cardiotoxins. |
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ISSN: | 1607-6729 1608-3091 |
DOI: | 10.1134/S1607672919040094 |