scholarly journals Alterations in electrical activity and membrane currents induced by intracellular oxygen-derived free radical stress in guinea pig ventricular myocytes.

1993 ◽  
Vol 72 (6) ◽  
pp. 1229-1244 ◽  
Author(s):  
R I Jabr ◽  
W C Cole
1999 ◽  
Vol 277 (2) ◽  
pp. H826-H833 ◽  
Author(s):  
Seiko Tanabe ◽  
Toshio Hata ◽  
Masayasu Hiraoka

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.


1997 ◽  
Vol 29 (5) ◽  
pp. 593-598 ◽  
Author(s):  
Shuichi Takagi ◽  
Yasuki Kihara ◽  
Tamotsu Mitsuiye ◽  
Zhuren Wang ◽  
Shigetake Sasayama

2006 ◽  
Vol 41 (6) ◽  
pp. 1072-1072
Author(s):  
Y WATANABE ◽  
C NIU ◽  
T IWAMOTO ◽  
K YAMASHITA ◽  
H SATOH ◽  
...  

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