The inhibitory effect of β-stimulation on the Na/K pump current in guinea pig ventricular myocytes is mediated by a cAMP-dependent PKA pathway

1998 ◽  
Vol 435 (4) ◽  
pp. 479-484 ◽  
Author(s):  
J. Gao ◽  
I. S. Cohen ◽  
R. T. Mathias ◽  
G. J. Baldo
Keyword(s):  
Guinea Pig ◽  
Ventricular Myocytes ◽  
Pump Current ◽  
Inhibitory Effect ◽  
Pka Pathway

scholarly journals Inhibition of Na-K pump current in guinea pig ventricular myocytes by dihydroouabain occurs at high- and low-affinity sites.

1989 ◽  
Vol 64 (6) ◽  
pp. 1063-1069 ◽  
Author(s):  
D J Mogul ◽  
H H Rasmussen ◽  
D H Singer ◽  
R E Ten Eick
Keyword(s):  
Guinea Pig ◽  
Ventricular Myocytes ◽  
Pump Current

scholarly journals Inhibitory effect of aprindine on Na+ /Ca2+ exchange current in guinea-pig cardiac ventricular myocytes

2002 ◽  
Vol 136 (3) ◽  
pp. 361-366 ◽  
Author(s):  
Yasuhide Watanabe ◽  
Takahiro Iwamoto ◽  
Munekazu Shigekawa ◽  
Junko Kimura
Keyword(s):  
Guinea Pig ◽  
Ventricular Myocytes ◽  
Inhibitory Effect ◽  
Exchange Current ◽  
Cardiac Ventricular Myocytes

scholarly journals Inhibitory Effect of Cibenzoline on Na+/Ca2+ Exchange Current in Guinea-Pig Cardiac Ventricular Myocytes

2012 ◽  
Vol 120 (1) ◽  
pp. 59-62 ◽  
Author(s):  
Tomomi Yamakawa ◽  
Yasuhide Watanabe ◽  
Hiroshi Watanabe ◽  
Junko Kimura
Keyword(s):  
Guinea Pig ◽  
Ventricular Myocytes ◽  
Inhibitory Effect ◽  
Exchange Current ◽  
Cardiac Ventricular Myocytes

scholarly journals Inhibitory effect of 2,3-butanedione monoxime (BDM) on Na+ /Ca2+ exchange current in guinea-pig cardiac ventricular myocytes

2001 ◽  
Vol 132 (6) ◽  
pp. 1317-1325 ◽  
Author(s):  
Yasuhide Watanabe ◽  
Takahiro Iwamoto ◽  
Isao Matsuoka ◽  
Satoko Ohkubo ◽  
Tomoyuki Ono ◽  
...  
Keyword(s):  
Guinea Pig ◽  
Ventricular Myocytes ◽  
Inhibitory Effect ◽  
Exchange Current ◽  
Butanedione Monoxime ◽  
Cardiac Ventricular Myocytes

Palmitoyl-L-carnitine acts like ouabain on voltage, current, and contraction in guinea pig ventricular cells

1995 ◽  
Vol 268 (3) ◽  
pp. H1027-H1036 ◽  
Author(s):  
J. B. Shen ◽  
A. J. Pappano
Keyword(s):  
Guinea Pig ◽  
Ventricular Myocytes ◽  
Present Report ◽  
Ionic Currents ◽  
Pump Current ◽  
Membrane Potentials ◽  
Cell Shortening ◽  
Ventricular Cells ◽  
Ramp Voltage ◽  
Inward Currents

We previously showed that palmitoyl-L-carnitine (L-PC) inhibits the Na/K pump current (INa/K). In the present report, we test the hypothesis that L-PC, like ouabain, should increase myocyte shortening. Membrane potentials or ionic currents were recorded simultaneously with cell shortening in single guinea pig ventricular myocytes at room temperature (22 degrees C). Like ouabain, L-PC (1 microM) reversibly depolarized the resting membrane, decreased action potential duration, and increased the amplitude of myocyte contractions. Neither L-PC nor ouabain had a significant effect on Ca current (ICa). When L-PC increased cell shortening during ramp voltage clamp, membrane current shifted inward at voltages negative to -20 mV and shifted outward at more positive voltages. Similar to toxic concentrations of ouabain, L-PC induced transient inward currents and aftercontractions. At concentrations that inhibit INa/K, L-PC acted like ouabain to produce characteristic effects on membrane potentials, currents, and cell contractions that were unrelated to significant changes in ICa. L-PC reduces surface negative charge of erythrocytes and myocytes (C. Gruver and A. J. Pappano, J. Mol. Cell. Cardiol. 25: 1275–1284, 1993), and we speculate that L-PC inhibits INa/K by this mechanism.

scholarly journals Steady-state current-voltage relationship of the Na/K pump in guinea pig ventricular myocytes.

1989 ◽  
Vol 94 (3) ◽  
pp. 511-537 ◽  
Author(s):  
D C Gadsby ◽  
M Nakao
Keyword(s):  
Steady State ◽  
Guinea Pig ◽  
Rate Constants ◽  
Ventricular Myocytes ◽  
Pump Current ◽  
Membrane Current ◽  
Negative Slope ◽  
Current Voltage ◽  
State Cycle ◽  
External K

Whole-cell currents were recorded in guinea pig ventricular myocytes at approximately 36 degrees C before, during, and after exposure to maximally effective concentrations of strophanthidin, a cardiotonic steroid and specific inhibitor of the Na/K pump. Wide-tipped pipettes, in combination with a device for exchanging the solution inside the pipette, afforded reasonable control of the ionic composition of the intracellular solution and of the membrane potential. Internal and external solutions were designed to minimize channel currents and Na/Ca exchange current while sustaining vigorous forward Na/K transport, monitored as strophanthidin-sensitive current. 100-ms voltage pulses from the -40 mV holding potential were used to determine steady-state levels of membrane current between -140 and +60 mV. Control experiments demonstrated that if the Na/K pump cycle were first arrested, e.g., by withdrawal of external K, or of both internal and external Na, then neither strophanthidin nor its vehicle, dimethylsulfoxide, had any discernible effect on steady-state membrane current. Further controls showed that, with the Na/K pump inhibited by strophanthidin, membrane current was insensitive to changes of external [K] between 5.4 and 0 mM and was little altered by changing the pipette [Na] from 0 to 50 mM. Strophanthidin-sensitive current therefore closely approximated Na/K pump current, and was virtually free of contamination by current components altered by the changes in extracellular [K] and intracellular [Na] expected to accompany pump inhibition. The steady-state Na/K pump current-voltage (I-V) relationship, with the pump strongly activated by 5.4 mM external K and 50 mM internal Na (and 10 mM ATP), was sigmoid in shape with a steep positive slope between about 0 and -100 mV, a less steep slope at more negative potentials, and an extremely shallow slope at positive potentials; no region of negative slope was found. That shape of I-V relationship can be generated by a two-state cycle with one pair of voltage-sensitive rate constants and one pair of voltage-insensitive rate constants: such a two-state scheme is a valid steady-state representation of a multi-state cycle that includes only a single voltage-sensitive step.

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