The effect of hypoxia-early reoxygenation on persistent sodium current in single ventricular myocytes of guinea pig / 中国应用生理学杂志

ABSTRACT

<p><b>AIM</b>To investigate the effect of hypoxia/early reoxygenation on persistent sodium current (I(Na.P)) in single ventricular myocytes of guinea pig and discuss its role and significance during this pathological condition.</p><p><b>METHODS</b>The whole cell patch clamp technology was used to record this current and study its change under the condition of hypoxia/reoxygenation model.</p><p><b>RESULTS</b>(1) With 0.5 Hz, 1 Hz and 2 Hz pulse frequency, the current density gap between the first and the eighth pulse of I(Na.P) was (0.021 +/- 0.014) pA/ pF, (0.097 +/- 0.014) pA/pF and (0.133 +/- 0.024) pA/pF (P < 0.01) respectively. (2) Depolarization with membrane holding potential of -150 - -80 mV respectively, I(Na.P) density attenuated gradually. (3) The amplitude of I(Na.P) was increased consistently with the prolongation of hypoxia time during hypoxia. (4) I(Na.P) was (0.500 +/- 0.125) pA/pF, (1.294 +/- 0.321) pA/pF and (0.988 +/- 0.189) pA/pF (P < 0.01, vs normoxia, respectively) during normoxia, hypoxia after 15 min and reoxygenation after 5 min, respectively.</p><p><b>CONCLUSION</b>These results indicate that I(Na.P) has great significance in arrhythmogenesis and calcium-overload, which causes the following postischemia and post hypoxia myocardial damage.</p>