Ouabain-induced negative frequency-force relationship in the isolated, blood-perfused dog atrium.
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چکیده
منابع مشابه
Ouabain-induced negative frequency-force relationship in the isolated, blood-perfused dog atrium.
Effects of ouabain, CaCl2 and verapamil on the frequency-force relationship (FFR) were investigated in the isolated, blood-perfused dog atrial muscle preparation. When ouabain (3 and 10 micrograms) or CaCl2 (0.5, 1 and 2 mg/min) was given into the sinus node artery, the contractile force of the atrial muscle, driven at a constant pacing rate of 2 Hz, increased dose-dependently. Verapamil (1 and...
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Isometric developed tension and rate of development of tension in the in situ atrium of the anesthetized dog have been shown to increase consistently with increasing heart rate over a wide range. This study thus definitely demonstrates that both the ascending and descending staircase effects occur in the dog atrium in situ. At high cardiac rates the velocity of force development may increase wi...
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Using an isolated, blood-perfused canine atrial preparation, we investigated the effects of omega-conotoxin GVIA (omega-CgTX), a blocker of N-type voltage-operated calcium channels, on the atrial contractile force and sinus rate. Omega-CgTX in a dose range of 0.3-3 nmol gradually attenuated the atrial contractile force in a dose-dependent manner, but did not affect the sinus rate, indicating th...
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In the isolated, blood-perfused dog atrium, strychnine evoked dose-dependent decreases in atrial rate and contractile force, and the negative cardiac effects were not influenced by atropine. Strychnine suppressed dose-dependently the negative chronotropic and inotropic responses to intramural parasympathetic nerve stimulation, but not the response to acetylcholine. These results suggest that st...
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Both bethanechol and physostigmine produced dose-dependent negative chrono-, dromo- and inotropic effects in the dog isolated atrial preparation. Within a relatively small dose of bethanechol and physostigmine, negative inotropic effect was clearly induced but no significant chrono- and dromotropic changes were observed. With a relatively large dose, the two cholinomimetics caused negative chro...
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ژورنال
عنوان ژورنال: Japanese Heart Journal
سال: 1986
ISSN: 0021-4868,1348-673X
DOI: 10.1536/ihj.27.223