Kir2.3 knock‐down decreases I_K1 current in neonatal rat cardiomyocytes

Abstract

Inward rectifier potassium Kir2.x channels mediate cardiac inward rectifier potassium currents (I K1 ). As a subunit of Kir2.x, the physiological role of Kir2.3 in native cardiomyocytes has not been reported. This study shows that Kir2.3 knock-down remarkably down-regulates Kir2.3 expression (Kir2.3 protein was reduced to 19.91 ± 3.24% on the 2nd or 3rd day) and I K1 current densities (at À120 mV, control vs. knockdown: À5.03 ± 0.24 pA/pF, n = 5 vs. À1.16 ± 0.19 pA/pF, n = 7, P < 0.001) in neonatal rat cardiomyocytes. The data suggest that Kir2.3 plays a potentially important role in I K1 currents in neonatal rat cardiomyocytes.

Postnatal developmental decline in I K1 in mouse ventricular myocytes isolated by the Langendorff perfusion method: comparison with the chunk method

“…Whereas Kir2.1 and 2.2 are more abundant in the day-14 and adult ventricles than in the day-0 ventricle, Kir2.3 is most abundant in the day-0 mouse ventricles, thus suggesting that there are also developmental changes in the expression patterns of Kir subunits. Previous workers have indicated the functional importance of Kir2.3 in cardiac I K1 in neonatal rat [11]. However, the present examination for the expression of Kir subunits at mRNA and protein levels can provide little convincing explanation for a postnatal developmental decrease in the density of I K1 , and futures studies are required to further elucidate the molecular basis for postnatal developmental changes in cardiac I K1 .…”

Extracellular pH regulates autophagy via the AMPK–ULK1 pathway in rat cardiomyocytes

“…Neonatal Sprague‐Dawley rats (1–3 days old) were provided by the Animal Center of the Third Military Medical University. Rat hearts were harvested and digested with pancreatin and then cultured according to the protocols published previously . Rat cardiomyocytes were cultured in Dulbecco's modified Eagle's medium (DMEM)/F‐12 supplemented with 10% fetal bovine serum and antibiotics.…”

Functional Characterization of Inward Rectifier Potassium Ion Channel in Murine Fetal Ventricular Cardiomyocytes

“…About 50% reduction in IK1 currents is observed in Kir2.2 -/-mouse cardiomyocytes [15]. In neonatal rat cardiomyocytes the Kir2.3 knockdown leads to IK1 current densities decreased by about 80% [16]. Moreover, Kir2.1 and Kir2.3 are found to differentially distribute in the canine atrium and ventricle [17].…”