Effects of electroacupuncture on cardiac and gastric activities in acute myocardial ischemia rats.

AIM To observe the effect of electroacupuncture (EA) of "Neiguan" (PC6) and "Gongsun" (SP4) on pathological changes of the heart and stomach in rats with acute myocardial ischemia (AMI), and to explore its underlying mechanism. METHODS Fifty Wistar rats were randomized into control, model, PC6, SP4 and PC6 + SP4 groups (n = 8 each group). An AMI model was established by occlusion of the descending anterior branch (DAB) of the left coronary artery. ECG-ST of cervico-thoracic lead and electrogastrogram (EGG) were recorded. EA was applied to PC6, SP4 and PC6 + SP4 groups, respectively. At the end of experiments, the rats were transcardically perfused with 4% paraformaldehyde, and the heart base myocardium, gastric antrum and duodenum tissues were sampled, sectioned and stained with a reduced form of nicotinamide-adenine dinucleotide phosphate (NADPH)-diaphorase histochemical method for displaying nitric oxide synthase (NOS) activity. RESULTS After AMI, ECG-ST values elevated. After EA, the elevated ECG-ST values at 20 min in PC6 group, at 30 min in PC6 + SP4 and SP4 groups had no significant differences in comparison with their respective basal values before AMI. Following AMI, the amplitude and frequency of slow waves of EGG decreased remarkably (P < 0.05). At 30 min after EA, the mean amplitude and frequency of slow waves of EGG in the three EA groups had no marked differences compared with their individual basal levels and those in the control group. After AMI, the mean integral grey values of NOS-positive product in myocardium, gastric antrum and duodenum tissues in the model group increased remarkably in comparison with the control group, while those in three EA groups were lower than those in the model group. No significant differences were found in ECG-ST and EGG improvement among the three EA groups. However, EA of PC6 had a better effect on ECG-ST and EA of PC4 had a better effect on EGG, respectively. CONCLUSION EA of PC6, SP4 and PC6 + SP4 can significantly promote the recovery of cardiac and gastric electrical activities after AMI, and up-regulate NOS expression in myocardium, gastric antrum and duodenum tissues.