Cardiac action potential and inotropic effect of noradrenaline and calcium

1975 ◽  
Vol 286 (4) ◽  
pp. 337-351 ◽  
Author(s):  
J. Quadbeck ◽  
M. Reiter
Keyword(s):  
Action Potential ◽  
Inotropic Effect ◽  
Cardiac Action Potential ◽  
Cardiac Action

Effects of Acetylcholine on Resting and Action Potentials, and on Contractile Force in the Ventricle Of Dolabella Auricularia

1974 ◽  
Vol 61 (3) ◽  
pp. 629-637
Author(s):  
ROBERT B. HILL
Keyword(s):  
Action Potential ◽  
Action Potentials ◽  
Contractile Force ◽  
Inotropic Effect ◽  
Cardiac Action Potential ◽  
Cardiac Action ◽  
Dolabella Auricularia ◽  
Isolated Ventricle

Acetylcholine (2x10-8 to 2x10-3 M depolarized the isolated ventricle of Dolabella auricularia. The depolarization was accompanied by a negatively inotropic effect from 2x10-8 M to 2x10-4 M, and by a positively tonotropic effect from 2x10-4 M to 2x10-3 M. The interaction of acetylcholine and 5-hydroxytryptamine was studied by artificially prolonging the plateau of the cardiac action potential by treatment with 5-HT. Acetylcholine had the effect of shortening the plateau established by 5-hydroxytryptamine. Force was reduced correspondingly.

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

scholarly journals Ceramide modulates HERG potassium channel gating by translocation into lipid rafts

2010 ◽  
Vol 299 (1) ◽  
pp. C74-C86 ◽  
Author(s):  
Sindura B. Ganapathi ◽  
Todd E. Fox ◽  
Mark Kester ◽  
Keith S. Elmslie
Keyword(s):  
Potassium Channels ◽  
Action Potential ◽  
Lipid Rafts ◽  
Negative Impact ◽  
Cardiac Action Potential ◽  
Cholesterol Depletion ◽  
Cardiac Action ◽  
Herg Channels ◽  
The Impact ◽  
Action Potential Repolarization

Human ether-à-go-go-related gene (HERG) potassium channels play an important role in cardiac action potential repolarization, and HERG dysfunction can cause cardiac arrhythmias. However, recent evidence suggests a role for HERG in the proliferation and progression of multiple types of cancers, making it an attractive target for cancer therapy. Ceramide is an important second messenger of the sphingolipid family, which due to its proapoptotic properties has shown promising results in animal models as an anticancer agent . Yet the acute effects of ceramide on HERG potassium channels are not known. In the present study we examined the effects of cell-permeable C6-ceramide on HERG potassium channels stably expressed in HEK-293 cells. C6-ceramide (10 μM) reversibly inhibited HERG channel current (IHERG) by 36 ± 5%. Kinetically, ceramide induced a significant hyperpolarizing shift in the current-voltage relationship (Δ V1/2 = −8 ± 0.5 mV) and increased the deactivation rate (43 ± 3% for τfast and 51 ± 3% for τslow). Mechanistically, ceramide recruited HERG channels within caveolin-enriched lipid rafts. Cholesterol depletion and repletion experiments and mathematical modeling studies confirmed that inhibition and gating effects are mediated by separate mechanisms. The ceramide-induced hyperpolarizing gating shift (raft mediated) could offset the impact of inhibition (raft independent) during cardiac action potential repolarization, so together they may nullify any negative impact on cardiac rhythm. Our results provide new insights into the effects of C6-ceramide on HERG channels and suggest that C6-ceramide can be a promising therapeutic for cancers that overexpress HERG.

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