The Beneficial Effect of Electro-acupuncture Given at PC6 (Neiguan-point) by the Increase in Cardiac Transient Outward K+ Current Channel Which Depends on the Gene and Protein Expressions in Artificially Induced Myocardial Ischemia Rats

This study explored the mechanism of electro-acupuncture (EA) at PC6 to improve the heart function by regulating the cardiac transient outward potassium current (= Ito) channel in myocardial ischemia (MI). Kv1.4 is the main component of the slow Ito (Ito.s) channel. Kv4.2 and Kv4.3 are the main components of the fast Ito (Ito.f) channel. KChIP2 is a compound protein of Ito channel. In this experiment, MI was induced by injecting isoproterenol in rats, and the gene and protein expressions of Kv1.4, Kv4.2, Kv4.3 and KChIP2 were lower [The gene and protein decreased (42.8 ± 4.3)% and (37.2 ± 4.7)% respectively.] than the control rats significantly (p < 0.05). After MI induction, the MI rats were divided into three groups, including PC6, LU7 (Lieque-point) and Non-acupoint group which were acupunctured at once a day for 7 days respectively. After EA at PC6 and LU7, the gene and protein expressions showed obvious increased [EA at PC6: the gene and protein increased (50.24 ± 5.4)% and (39.14 ± 5.3)% respectively. EA at LU7: the gene and protein increased (24.6 ± 2.8)% and (22.04 ± 5.5)% respectively] and they are all higher than MI rats significantly (p < 0.05). EA at PC6 and LU7 showed the same variation, and the effects of EA at PC6 and LU7 were better than Non-acupuncture-point (p < 0.05). The effects of EA at PC6 were significantly better [The gene and protein increased (19.74 ± 2.7)% and (14.14 ± 4.4)% respectively] than LU7 (p < 0.05). PC6 is an acupoint of the pericardium meridian, and the pericardium meridian which corresponds to adrenal gland according to Omura Y's research, can affect the heart function directly LU7 belong to the lung meridian, and the lung plays an important factor in blood circulation according to TCM. So PC6 is more effective than LU7 on heart function regulation. The results suggested that PC6 showed the target effect of meridian specificity on regulating the Kv channel in MI.