RESUMO
AIM: The aim was to study the effect of Allitridum (Allicin) on the heterologous expression of the late sodium current on the ΔKPQ-SCN5A mutations in HEK293 cells, with a view to screening new drugs for the treatment of long QT syndrome type 3 (LQT3). METHODS AND RESULTS: The ΔKPQ-SCN5A plasmid was transiently transferred into HEK293 cells by liposome technology and administered by extracellular perfusion, and the sodium current was recorded by whole-cell patch-clamp technology. Application of Allicin 30 µM reduced the late sodium current (I Na,L ) of the Nav1.5 channel current encoded by ΔKPQ-SCN5A from 1.92 ± 0.12 to 0.65 ± 0.03 pA/pF (P < 0.01, n = 15), which resulted in the decrease of I Na,L /I Na,P (from 0.94% ± 0.04% to 0.32% ± 0.02%). Furthermore, treatment with Allicin could move the steady-state inactivation of the channel to a more negative direction, resulting in an increase in channel inactivation at the same voltage, which reduced the increase in the window current and further increased the inactivation of the channel intermediate state. However, it had no effect on channel steady-state activation (SSA), inactivation mechanics, and recovery dynamics after inactivation. What's more, the Nav1.5 channel protein levels of membrane in the ΔKPQ-SCN5A mutation were enhanced from 0.49% ± 0.04% to 0.76% ± 0.02% with the effect of 30 mM Allicin, close to 0.89% ± 0.02% of the WT. CONCLUSION: Allicin reduced the late sodium current of ΔKPQ-SCN5A, whose mechanism may be related to the increase of channel steady-state inactivation (SSI) and intermediate-state inactivation (ISI) by the drug, thus reducing the window current.
RESUMO
OBJECTIVE: To study the effect of allitridum on the transient outward potassium current (Ito) of ventricular myocytes in heart failure (HF). METHODS: The dual enzymatic method was used to separate single ventricular myocytes from Sprague Dawley rats. Patch-clamping was used to record Ito and analyze the effect of allitridum on the current. RESULTS: The Ito current had a significant decrease in the HF group, compared with the control group. The density of Ito in the HF group was increased after treatment of allitridum (30 µmol/L). The peak current densities of Ito were enhanced in the HF group from 6.01 ± 0.30 pA/pF to 8.41 ± 0.54 pA/pF (P < 0.01) at +50 mV after treatment with allitridum (30 µmol/L). We also determined the effect of allitridum on the gating mechanism of the Ito in the HF group. CONCLUSIONS: We found that allitridum increased the Ito by accelerating the activation of channels and shortened the time constants of inactivation, and allitridum decreased the remodeling of Ito in ventricular myocytes of rats with HF.
RESUMO
This study was designed to test the allitridum (All) activity in correction of sodium current decrease caused by SCN5A-F1473S mutation in HEK293 cells. The result may provide a theoretical basis for screening of new drugs in the treatment of Brugada syndrome. We transferred SCN5A-F1473S channel plasmids into HEK293 cells in a transient transfection. All was administrated acutely and chronically using extracellular irrigation flow and co-culture model. The concentration of All was 30 μmol·L-1. We used whole cell patch clamp technique in voltage clamp mode to record current and gating kinetics. In order to explore the rescue function of All on decreased sodium peak current, we used confocal microscopy and Western blot to detect the expression of channel proteins in the cell membrane. We found a significant increase in sodium peak current of the 30 μmol·L-1 All HEK293 cells (269.8±16.6 pA/pF, PPV1/2,inact returns to -79.5±2.4 mV, PPPSCN5A-F1473S mutation cells. We consider that the main mechanism may be related to the reduced channel inactivation by the drug with an improvement of the migration barrier of the mutational channel.
