Adrenaline and the plateau phase of the cardiac action potential

1969 ◽  
Vol 313 (4) ◽  
pp. 300-315 ◽  
Author(s):  
Edward Carmeliet ◽  
Johan Vereecke
Keyword(s):  
Action Potential ◽  
Cardiac Action Potential ◽  
Plateau Phase ◽  
Cardiac Action

AN ANALYSIS OF CONTROL OF THE VENTRICLE OF THE MOLLUSC MERCENARIA MERCENARIA

1993 ◽  
Vol 179 (1) ◽  
pp. 47-61
Author(s):  
C. L. Devlin
Keyword(s):  
Action Potential ◽  
Mercenaria Mercenaria ◽  
Lanthanum Chloride ◽  
Cardiac Action Potential ◽  
Extracellular Potassium ◽  
Plateau Phase ◽  
Progressive Reduction ◽  
Barium Ions ◽  
Cardiac Action ◽  
Ionophore Monensin

During spontaneous beating (autorhythmicity) in the bivalve ventricle, the cardiac action potential (AP) was generated by calcium (Ca2+) and sodium (Na+) influx. The initial fast rising phase (the ‘spike’) of the cardiac AP was dependent on extracellular Ca2+ concentration, whereas the slow plateau phase was Na+-dependent. The initial fast rising phase of the cardiac AP was abolished by treatment with a Ca2+-free saline or inorganic Ca2+ entry blockers, such as lanthanum chloride or cobalt. Conversely, this fast rising phase of the AP was potentiated by treatment with barium ions, the dihydropyridine-sensitive Ca2+ channel agonist Bay K 8644 or, unexpectedly, by the organic Ca2+ entry blocker diltiazem. The force of systolic beating was directly proportional to the amplitude of the fast rising phase of the cardiac AP. The Ca2+-dependent, fast rising phase of the AP was modulated by the level of extracellular Na+. Both the amplitude of the fast rising phase of the AP and coupled systolic force were increased by progressive reduction of extracellular Na+ concentration. The slow plateau phase was abolished by treatment with a Na+-free saline and potentiated by the Na+ ionophore monensin. The size of the Na+-dependent plateau was modulated by the level of extracellular Ca2+. When extracellular Ca2+ was removed from the bathing saline, both the amplitude and duration of the plateau phase were increased. Conversely, restoring extracellular Ca2+ to physiological levels decreased the size of the Na+-dependent plateau. Autorhythmicity was dependent on the level of extracellular potassium. In the absence of K+, neither a Ca2+-dependent fast rising phase nor a Na+-dependent plateau phase was recorded.

Effects of 5-Hydroxytryptamine on Action Potentials and on Contractile Force in the Ventricle of Dolabella Auricularia

1974 ◽  
Vol 61 (2) ◽  
pp. 529-539
Author(s):  
ROBERT B. HILL
Keyword(s):  
Action Potential ◽  
Action Potentials ◽  
Entire Range ◽  
Contractile Force ◽  
Cardiac Action Potential ◽  
Force Of Contraction ◽  
Plateau Phase ◽  
Cardiac Action ◽  
Dolabella Auricularia

1. Concentrations of 5-hydroxytryptamine from 10-8 to 10-5M had the effect of starting quiescent ventricles, with a slow slight depolarization followed by the onset of beating, with hyperpolarization between beats. 2. Concentrations of 5-hydroxytryptamine from 10-7 to 10-3M had the effect of prolonging the cardiac action potential and increasing force. Over the entire range, an increase in concentration led to an increase in the duration and amplitude of the plateau phase of the action potential, and an increase in force of contraction.

scholarly journals Stochastic pacing reveals the propensity to cardiac action potential alternans and uncovers its underlying dynamics

2016 ◽  
Vol 594 (9) ◽  
pp. 2537-2553 ◽  
Author(s):  
Yann Prudat ◽  
Roshni V. Madhvani ◽  
Marina Angelini ◽  
Nils P. Borgstom ◽  
Alan Garfinkel ◽  
...  
Keyword(s):  
Action Potential ◽  
Cardiac Action Potential ◽  
Cardiac Action

scholarly journals Dynamics of the late Na+ current during cardiac action potential and its contribution to afterdepolarizations

2013 ◽  
Vol 64 ◽  
pp. 59-68 ◽  
Author(s):  
Balazs Horvath ◽  
Tamas Banyasz ◽  
Zhong Jian ◽  
Bence Hegyi ◽  
Kornel Kistamas ◽  
...  
Keyword(s):  
Action Potential ◽  
Cardiac Action Potential ◽  
Na Current ◽  
Cardiac Action
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