scholarly journals Developmental changes in the pacemaker current and membrane currents of the guinea pig myocardium.

1996 ◽  
Vol 107 (6) ◽  
pp. 259-272
Author(s):  
Koki SHIGENOBU ◽  
Hikaru TANAKA ◽  
Hiroyasu SATOH
Keyword(s):  
Guinea Pig ◽  
Membrane Currents ◽  
Developmental Changes ◽  
Pacemaker Current

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 Developmental changes in potassium and calcium currents of guinea-pig ventricular myocytes

1995 ◽  
Vol 67 ◽  
pp. 130
Author(s):  
Yoshimitsu Kato ◽  
Naoki Agata ◽  
Hikaru Tanaka ◽  
Koki Shiaenobu
Keyword(s):  
Guinea Pig ◽  
Ventricular Myocytes ◽  
Calcium Currents ◽  
Developmental Changes

scholarly journals Developmental Changes in Sodium Nitroprusside and Atrial Natriuretic Factor Mediated Relaxation in the Guinea Pig Aorta

1990 ◽  
Vol 27 (4) ◽  
pp. 392-395 ◽  
Author(s):  
Venkataraman Balaraman ◽  
Linda K Kullama ◽  
David Easa ◽  
Jean E Robillard ◽  
Glenn M Hashiro ◽  
...  
Keyword(s):  
Guinea Pig ◽  
Sodium Nitroprusside ◽  
Atrial Natriuretic Factor ◽  
Developmental Changes ◽  
Natriuretic Factor ◽  
Atrial Natriuretic
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