Reduction of calcium-independent transient outward potassium current density in DOCA salt hypertrophied rat ventricular myocytes

1994 ◽  
Vol 427 (1-2) ◽  
pp. 47-55 ◽  
Author(s):  
Alain Coulombe ◽  
Abdelhaq Momtaz ◽  
Paulette Richer ◽  
Bernard Swynghedauw ◽  
Edouard Coraboeuf
Keyword(s):  
Current Density ◽  
Potassium Current ◽  
Ventricular Myocytes ◽  
Transient Outward Potassium Current ◽  
Rat Ventricular Myocytes ◽  
Outward Potassium Current

Effect of antipsychotic drug perphenazine on fast sodium current and transient outward potassium current in rat ventricular myocytes

2009 ◽  
Vol 380 (2) ◽  
pp. 125-133 ◽  
Author(s):  
Markéta Bébarová ◽  
Peter Matejovič ◽  
Michal Pásek ◽  
Dagmar Jansová ◽  
Milena Šimurdová ◽  
...  
Keyword(s):  
Antipsychotic Drug ◽  
Potassium Current ◽  
Ventricular Myocytes ◽  
Sodium Current ◽  
Transient Outward Potassium Current ◽  
Rat Ventricular Myocytes ◽  
Outward Potassium Current ◽  
Fast Sodium Current

scholarly journals Neuropeptide Y increases 4-aminopyridine-sensitive transient outward potassium current in rat ventricular myocytes

2002 ◽  
Vol 136 (7) ◽  
pp. 1079-1079
Author(s):  
M P Heredia ◽  
M Fernandez-Velasco ◽  
G Benito ◽  
C Delgado
Keyword(s):  
Neuropeptide Y ◽  
Potassium Current ◽  
Ventricular Myocytes ◽  
Transient Outward Potassium Current ◽  
Rat Ventricular Myocytes ◽  
Outward Potassium Current

scholarly journals Neuropeptide Y increases 4-aminopyridine-sensitive transient outward potassium current in rat ventricular myocytes

2002 ◽  
Vol 135 (7) ◽  
pp. 1701-1706 ◽  
Author(s):  
M P Heredia ◽  
M Fernández-Velasco ◽  
G Benito ◽  
C Delgado
Keyword(s):  
Neuropeptide Y ◽  
Potassium Current ◽  
Ventricular Myocytes ◽  
Transient Outward Potassium Current ◽  
Rat Ventricular Myocytes ◽  
Outward Potassium Current

scholarly journals Depressed transient outward potassium current density in catecholamine-depleted rat ventricular myocytes

2002 ◽  
Vol 282 (4) ◽  
pp. H1237-H1247 ◽  
Author(s):  
Gilles Bru-Mercier ◽  
Edith Deroubaix ◽  
Delphine Rousseau ◽  
Alain Coulombe ◽  
Jean-François Renaud
Keyword(s):  
Potassium Current ◽  
Ventricular Myocytes ◽  
Cell Voltage ◽  
Wistar Rat ◽  
Perfused Heart ◽  
Transient Outward Potassium Current ◽  
Rat Ventricular Myocytes ◽  
Control Value ◽  
Steady State Inactivation ◽  
Outward Potassium Current

The effect of catecholamine depletion (induced by prior treatment with reserpine) was studied in Wistar rat ventricular myocytes using whole cell voltage-clamp methods. Two calcium-independent outward currents, the transient outward potassium current ( I to) and the sustained outward potassium current ( I sus), were measured. Reserpine treatment decreased tissue norepinephrine content by 97%. Action potential duration in the isolated perfused heart was significantly increased in reserpine-treated hearts. In isolated ventricular myocytes, I to density was decreased by 49% in reserpine-treated rats. This treatment had no effect on I sus. The I tosteady-state inactivation-voltage relationship and recovery from inactivation remained unchanged, whereas the conductance-voltage activation curve for reserpine-treated rats was significantly shifted (6.7 mV) toward negative potentials. The incubation of myocytes with 10 μM norepinephrine for 7–10 h restored I to, an effect that was abolished by the presence of actinomycin D. Norepinephrine (0.5 μM) had no effect on I to. However, in the presence of both 0.5 μM norepinephrine and neuropeptide Y (0.1 μM), I to density was restored to its control value. These results suggest that the sympathetic nervous system is involved in I to regulation. Sympathetic norepinephrine depletion decreased the number of functional channels via an effect on the α-adrenergic cascade and norepinephrine is able to restore expression of I to channels.

Effect of haloperidol on transient outward potassium current in rat ventricular myocytes

2006 ◽  
Vol 550 (1-3) ◽  
pp. 15-23 ◽  
Author(s):  
Markéta Bébarová ◽  
Peter Matejovič ◽  
Michal Pásek ◽  
Marie Nováková
Keyword(s):  
Potassium Current ◽  
Ventricular Myocytes ◽  
Transient Outward Potassium Current ◽  
Rat Ventricular Myocytes ◽  
Outward Potassium Current

Abstract 16953: Role of the Fast Transient Outward Current Ito,f in Shaping Action Potential Waveforms in Human iPSC-derived Cardiomyocytes

Circulation ◽  
2014 ◽  
Vol 130 (suppl_2) ◽  
Author(s):  
Scott Marrus ◽  
Steven Springer ◽  
Rita Martinez ◽  
Edward Dranoff ◽  
Rebecca Mellor ◽  
...  
Keyword(s):  
Action Potential ◽  
Potassium Current ◽  
Ventricular Myocytes ◽  
Current Clamp ◽  
Transient Outward Potassium Current ◽  
Fast Transient ◽  
Human Ipsc ◽  
Outward Potassium Current ◽  
Upstroke Velocity

Abnormalities of a key repolarizing cardiac potassium current, the fast transient outward potassium current, I to,f , are associated with both heart failure and congenital arrhythmia syndromes. However, the precise role of I to,f in shaping action potential waveforms remains unclear. This study was designed to define the functional role of the fast transient outward potassium current, I to,f , in shaping action potentials in human iPSC-derived cardiomyocytes (iPSC-CMs). Most iPSC-CMs (29 of 43 cells) demonstrated spontaneous electrical activity, slow upstroke velocity (63±71 V/s), a wide range of action potential durations (APD90 = 860±722 ms) and heterogeneous action potential waveforms. Using dynamic current clamp, a modeled human ventricular inwardly rectifying K + current, I K1 , was introduced into iPSC-CMs, resulting in silencing of spontaneous activity, hyperpolarization of the resting membrane potential (RMP = -90±3 mV), increased peak upstroke velocity (dV/dt = 346±71 V/s) and decreased APD90 (420±211 ms) to values similar to those recorded in isolated adult human ventricular myocytes (RMP = -84±3 mV, dV/dt = 348±101 V/s and APD90 = 468±133 ms, all p>0.05). Importantly, a ventricular-like action potential waveform was observed in 25 of the 26 cells studied following the dynamic clamp addition of I K1 . Using these cells as a model of human ventricular myocytes, further dynamic current clamp experiments introduced a modeled human fast transient outward K + current, I to,f , and revealed that increasing in the amplitude of I to,f results in an increase in the phase 1 notch and a progressive shortening of the action potential duration in iPSC-CMs. Together, the experiments here demonstrate that combining human iPSC-CMs with the power of the dynamic current clamp technique to modulate directly and precisely the “expression” of individual ionic currents provides a novel and quantitative approach to defining the roles of specific ionic conductances in regulating the excitability of human cardiomyocytes.

Sign in / Sign up

Export Citation Format

Share Document