[Human inward rectifying potassium current and Kir2.1 mRNA expression in myocytes isolated from patients with chronic atrial fibrillation].
OBJECTIVE
To compare the changes of both inward rectifying K(+) (Kir) current(I(k1)) density and mRNA expression level of Kir2.1, a major subfamily of Kir in chronic human atrial fibrillation (CAF) with those in normal sinus rhythm (NSR).


METHODS
I(k1) density was measured with whole-cell patch clamp technique in single myocyte isolated by an enzymatic dissociation method from right atrial appendages in patients with CAF (n = 8) and those with NSR (n = 12). The mRNA expression levels of Kir2.1 was determined in right atrial appendages from CAF (n = 19) and NSR (n = 18) by semiquantitative reverse-transcription polymerase chain reaction (RT-PCR).


RESULTS
The average resting membrane potentials were similar between CAF and NSR (-78.95 mV +/- 4.67 mV and -70.22 mV +/- 11.08 mV, P>0.05). I(k1) density in single myocyte significantly increased at hyperpolarized potential level (-100 mV) in CAF compared to that in NSR (-9.59 pA/pF +/- 2.47 pA/pF vs. -5.58 pA/pF +/- 2.52 pA/pF, P<0.01). The mRNA level of Kir2.1 was also significantly higher in CAF than that of NSR (0.50+/-0.16 vs. 0.34+/-0.09, P<0.05).


CONCLUSIONS
The data suggest that Kir2.1 up-regulation and I(k1) current increase might contribute to the electrical remodeling in CAF patients.
Zhang
Yu
Y
Institute of Myocardium Electrophysiology, Luzhou Medical College, Luzhou 646000, Sichuan, China.
Zeng
Xiao-rong
XR
Yang
Yan
Y
Zhang
Biao
B
Liu
Zhi-fei
ZF
Li
Miao-ling
ML
Zhou
Wen
W
Pei
Jie
J
D001281:Atrial Fibrillation / Q000235:genetics / Q000378:metabolism* / Q000503:physiopathology; D015870:Gene Expression; D006801:Humans; D032383:Myocytes, Cardiac / Q000378:metabolism* / Q000502:physiology; D018408:Patch-Clamp Techniques; D024661:Potassium Channels, Inwardly Rectifying / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics
C489457:KCNJ2 protein, human; D024661:Potassium Channels, Inwardly Rectifying; D012333:RNA, Messenger