Tetrodotoxin exerts a large frequency-dependent depression of the maximum rate of rise of action potentials in guinea pig ventricular myocytes

1986 ◽  
Vol 406 (6) ◽  
pp. 645-647 ◽  
Author(s):  
Toshifumi Watanabe ◽  
Terence F. McDonald
Keyword(s):  
Guinea Pig ◽  
Action Potentials ◽  
Maximum Rate ◽  
Ventricular Myocytes ◽  
Frequency Dependent ◽  
Large Frequency ◽  
Maximum Rate Of Rise

scholarly journals Use-dependent blocking action of newly developed lidocaine-analogs on maximum rate of rise of action potentials in guinea pig papillary muscle.

1987 ◽  
Vol 28 (2) ◽  
pp. 273-285 ◽  
Author(s):  
Junji TOYAMA ◽  
Itsuo KODAMA ◽  
Takahiro KUSUNOKI ◽  
Takafumi ISHIHARA ◽  
Yoshikazu HATTORI ◽  
...  
Keyword(s):  
Guinea Pig ◽  
Papillary Muscle ◽  
Action Potentials ◽  
Maximum Rate ◽  
Lidocaine Analogs ◽  
Maximum Rate Of Rise

Effects of estrogen on action potential and membrane currents in guinea pig ventricular myocytes

1999 ◽  
Vol 277 (2) ◽  
pp. H826-H833 ◽  
Author(s):  
Seiko Tanabe ◽  
Toshio Hata ◽  
Masayasu Hiraoka
Keyword(s):  
Guinea Pig ◽  
Action Potential ◽  
Action Potentials ◽  
Voltage Dependence ◽  
Ventricular Myocytes ◽  
Membrane Currents ◽  
Patch Clamp Technique ◽  
17Β Estradiol ◽  
Electrophysiological Effects ◽  
Ionic Basis

To explore a possible ionic basis for the prolonged Q-T interval in women compared with that in men, we investigated the electrophysiological effects of estrogen in isolated guinea pig ventricular myocytes. Action potentials and membrane currents were recorded using the whole cell configuration of the patch-clamp technique. Application of 17β-estradiol (10–30 μM) significantly prolonged the action potential duration (APD) at 20% (APD20) and 90% repolarization (APD90) at stimulation rates of 0.1–2.0 Hz. In the presence of 30 μM 17β-estradiol, APD20 and APD90 at 0.1 Hz were prolonged by 46.2 ± 17.1 and 63.4 ± 11.7% of the control ( n = 5), respectively. In the presence of 30 μM 17β-estradiol the peak inward Ca2+ current ( I CaL) was decreased to 80.1 ± 2.5% of the control ( n = 4) without a shift in its voltage dependence. Application of 30 μM 17β-estradiol decreased the rapidly activating component of the delayed outward K+ current ( I Kr) to 63.4 ± 8% and the slowly activating component ( I Ks) to 65.8 ± 8.7% with respect to the control; the inward rectifier K+ current was barely affected. The results suggest that 17β-estradiol prolonged APD mainly by inhibiting the I Kcomponents I Krand I Ks.

scholarly journals Frequency-dependent block of T-type Ca2+ current by efonidipine in guinea-pig ventricular myocytes

2000 ◽  
Vol 82 ◽  
pp. 195
Author(s):  
Junya Kase ◽  
Haruko Masumiya ◽  
Yoshio Tanaka ◽  
Hikaru Tanaka ◽  
Koki Shigenobu
Keyword(s):  
Guinea Pig ◽  
Ventricular Myocytes ◽  
Frequency Dependent

scholarly journals Effects of BDF 9198 on action potentials and ionic currents from guinea-pig isolated ventricular myocytes

2000 ◽  
Vol 130 (8) ◽  
pp. 1753-1766 ◽  
Author(s):  
K H Yuill ◽  
M K Convery ◽  
P C Dooley ◽  
S A Doggrell ◽  
J C Hancox
Keyword(s):  
Guinea Pig ◽  
Action Potentials ◽  
Ventricular Myocytes ◽  
Ionic Currents ◽  
Isolated Ventricular Myocytes
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