Early down-regulation of K+ channel genes and currents in the postinfarction heart.

摘要: Down-Regulation oi K+ Channel Genes and Currents. Introduction: Down-regulaticn of key channel subunit gene expression currents is a universal response to cardiac hypertrophy, whatever the cause, including postmyocdardial infarction (post-Ml) remodeled heart. Methods Results: We investigated hypothesis that down-regulation genes post-MI occurs early before significant hypertrophy noninfarcted myocardium could be detected. (1) incidence induced ventricular tachyar-rhythmias (VT) in 3-day rat heart; (2) action potential (AP) characteristics isolated left (LV) myocytes from sham-operated (3) time course changes outward Ito-fast(f) Ikin 4-week LV compared with animals; (4) messenger protein levels Kv2.1, Kv4.2. Kv4.3 right ventricle heart. Sustained VT was 6 10 rats none 8 sham rats. The membrane capacitance not significantly different control, whereas higher, reflecting development hypertrophy. AP duration increased density Ito-f Ik were decreased sham. reduced Ito, did differ myocytes, further at 4 weeks post-MI. correlated Kv4.2/Kv4.3 Kv2.l, respectively. Conclusion: These results support current may dissociated slower contribute arrhythmogenesis