Effects of ATP on the membrane currents and tension components of bullfrog atrial muscle.
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Adenosine Triphosphate↗
Biomedical subjects
A Yatani
Publications and source records attributed to A Yatani.
[Dynamic energy participation in electrogenesis of the myocardium (author's transl)].
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Acetylcholine↗
The agonist effect of dihydropyridines on Ca channels.
Dihydropyridines (DHP) have great potential for clinical use because of their inotropic and vasomotor effects. The mechanism of action is unknown although Ca currents have been implicated. Here we report measurements of single channel and whole cell cardiac Ca currents after application of two DHP agonists BAY K 8644 and CGP 28 392. Whole cell Ca currents from individual myocytes were increased and the 50% effective doses (ED50) were similar to those reported for contractility in rabbit aorta and guinea pig heart and catecholamine release from cat adrenal glands. The measured ED50 was also consistent with the apparent dissociation constant (Kd) of a high affinity binding site present in cardiac sarcolemmal vesicles. We propose that the molecular basis for these results is an increase in the probability that a single Ca channel, having opened and closed, will subsequently re-open during membrane depolarization. At high concentrations of BAY K 8644 and in the presence of 96 mM Ba, different effects are observed, primarily a marked prologation of open time.
3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethy↗
Membrane calcium current in cardiac excitation: effects of ATP and related substances and sodium pump on bullfrog atrium.
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Adenosine Triphosphate↗