[Effects of allitridum on rapidly delayed rectifier potassium current in HEK293 cell line].
OBJECTIVE
To study the effect of allitridum on rapidly delayed rectifier potassium current (IKr) in HEK293 cell line.


METHODS
HEK293 cells were transiently transfected with HERG channel cDNA plasmid pcDNA3.1 via Lipofectamine. Allitridum was added to the extracellular solution by partial perfusion after giga seal at the final concentration of 30 µmol/L. Whole-cell patch clamp technique was used to record the HERG currents and gating kinetics before and after allitridum exposure at room temperature.


RESULTS
The amplitude and density of IHERG were both suppressed by allitridum in a voltage-dependent manner. In the presence of allitridum, the peak current of IHERG was reduced from 73.5∓4.3 pA/pF to 42.1∓3.6 pA/pF at the test potential of +50 mV (P<0.01). Allitridum also concentration-dependently decreased the density of the IHERG. The IC50 of allitridum was 34.74 µmol/L with a Hill coefficient of 1.01. Allitridum at 30 µmol/L caused a significant positive shift of the steady-state activation curve of IHERG and a markedly negative shift of the steady-state inactivation of IHERG, and significantly shortened the slow time constants of IHERG deactivation.


CONCLUSIONS
Allitridum can potently block IHERG in HEK293 cells, which might be the electrophysiological basis for its anti-arrhythmic action.
Department of Cardiology, Provincial Clinical Medicine College of Fujian Medical University, Fuzhou 350001, China. E-mail: fjzhangjiancheng@126.com.
Jiancheng
J
Zhang
Kun
K
Lin
Zhixiong
Z
Wei
Qian
Q
Chen
Li
L
Liu
Xiaojing
X
Zhao
Ying
Y
Zhao
Bin
B
Xu
Xi
X
Chen
Yang
Y
Li
D000498:Allyl Compounds / Q000494:pharmacology*; D000889:Anti-Arrhythmia Agents; D051668:Delayed Rectifier Potassium Channels / Q000187:drug effects*; D051638:Ether-A-Go-Go Potassium Channels; D057809:HEK293 Cells / Q000187:drug effects; D006801:Humans; D018408:Patch-Clamp Techniques; D026902:Potassium Channel Blockers / Q000494:pharmacology*; D013440:Sulfides / Q000494:pharmacology*; D014162:Transfection
D000498:Allyl Compounds; D000889:Anti-Arrhythmia Agents; D051668:Delayed Rectifier Potassium Channels; D051638:Ether-A-Go-Go Potassium Channels; D026902:Potassium Channel Blockers; D013440:Sulfides; C042577:diallyl trisulfide