Objective: To observe the effect of electroacupuncture (EA) of "Neiguan" (PC 6) and "Zusanli" (ST 36) on c-fos expression in the nucleus of the solitary tract (NTS)and ischemic electrocardiogram (ECG) in acute myocardial ischemia (AMI) rats, so as to study the role of NTS in EA-induced improvement of AMI.
Methods: Thirty-six male SD rats were randomly divided into control, model, ST 36, PC 6, "Pianli" (LI 6), and "Heyang" (BL 55) groups, with 6 cases in each. AMI model was established by intraperitoneal injection of Isoproterenol (5 mg/kg). EA (4 Hz/20 Hz, 1 mA) was applied to PC 6, ST 36, LI 6 and BL 55 for 20 min separately. c-fos expression in the NTS was detected by immunohistochemistry and ECG-ST(II) was recorded before and after AMI and EA.
Results: (1) Compared to control group, ECG-ST(II) of model group elevated significantly, while in comparison with model group, ECG-ST(II) values of ST 36 and PC 6 groups decreased significantly (P < 0.01), suggesting an improvement of AMI after EA. No significant changes of ECG-ST(II) were found in LI 6 and BL 55 groups (P > 0.05). (2) The number of fos-immunoreaction (fos-IR) positive neurons in the NTS in ST 36 and PC 6 groups was significantly lower than that in model, LI 6 and BL 55 groups (P < 0.01).
Conclusion: EA of PC 6 and ST 36 can improve ischemic ECG in AMI rats and NTS is one of the centers for integrating cardiac functional activity and information from EA of PC 6 and ST 36.