Open AccessEffect of hydrogen peroxide on persistent sodium current in guinea pig ventricular myocytes 1
Author(s) -
MA Jihua,
LUO Antao,
ZHANG Peihua
Publication year - 2005
Publication title -
acta pharmacologica sinica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.514
H-Index - 90
eISSN - 1745-7254
pISSN - 1671-4083
DOI - 10.1111/j.1745-7254.2005.00154.x
Subject(s) - guinea pig , hydrogen peroxide , glutathione , sodium , myocyte , chemistry , mole , medicine , patch clamp , endocrinology , biophysics , biochemistry , biology , enzyme , receptor , organic chemistry
Aim: To study the effect of hydrogen peroxide (H 2 O 2 ) on persistent sodium current ( I Na. P) in guinea pig ventricular myocytes. Methods: The whole‐cell, cell‐attached, and inside‐out patch‐clamp techniques were applied on isolated ventricular myocytes from guinea pig. Results: H 2 O 2 (0.1 mmol/L, 0.5 mmol/L and 1.0 mmol/L) increased the amplitude of whole‐cell I Na.P in a concentration‐dependent manner, and glutathione (GSH 1 mmol/L) reversed the increased I Na.P. H 2 O 2 (1 mmol/L) increased persistent sodium channel activity in cell‐attached and inside out patches. The mean open probability was increased from control values of 0.015±0.004 and 0.012±0.003 to 0.106±0.011 and 0.136±0.010, respectively ( P < 0.01 vs control). They were then decreased to 0.039±0.024 and 0.027±0.006, respectively, after the addition of 1 mmol/L GSH ( P < 0.01 vs H 2 O 2 ). The time when open probability began to increase and reached a maximum was shorter in inside out patches than that in cell‐attached patches (4.8±1.0 min vs 11.5±3.9 min, P < 0.01; 9.6±1.6 min vs 18.7±4.7 min, P < 0.01). Conclusion: H 2 O 2 increased the I Na.P of guinea pig ventricular myocytes in a concentration‐dependent manner, possibly by directly oxidating the cell membrane.