Objective: To explore the mechanism of electroacupuncture(EA) of "Neiguan"(PC 6) in relieving tachyarrhythmia in rats.Methods: Forty Wistar rats were randomly divided into normal control

model

PC-6

and non-acupoint groups

with 10 cases in each group.Tachyarrhythmia model was established by sublingual venous injection of 0.002% Aconitine((1 mL/kg)).EA(dense-sparse waves

(2/20 Hz)

2-(3 mA)) was applied to bilateral "Neiguan"(PC 6) or non-acupoints(the prominence sites of the bilateral shoulder deltoid muscles) for(10 min) after successful establishment of tachyarrhythmia.The heart rates were recorded

and myocardial stimulatory G-protein(Gs) mRNA expression was detected by using reverse transcription-polymerase chain reaction(RT-PCR) method.Results: After injection of Aconitine

the heart rate of model group increased significantly compared with normal control group(P<0.01)

and ventricular tachyarrhythmia and ventricular premature beat appeared;after acupuncture of "Neiguan"(PC 6)

the rat's heart recovered its normal sinus rhythm in PC-6 group

while the arrhythmia and heart rate of non-acupoint group had no marked recovery.Compared with normal control group

the heart rate of non-acupoint group increased apparently(P<0.01).In comparison with normal control group

the optical density(OD) values of Gs mRNA expression of model group and non-acupoint group increased significantly(P<0.01);while compared with model group

the OD value of PC-6 group decreased considerably(P<0.01)

and no significant difference was found between model and non-acupoint group in OD values(P>0.05).It suggested that EA could downregulate the expression of Gs mRNA.Conclusion: EA of "Neiguan"(PC 6) can correct Aconitine induced increase of heart rate and tachyarrhythmia which is related to its effect in reducing the upregulated expression of Gs mRNA in rats with tachyarrhythmia.