[Effects of Electroacupuncture Stimulation of "Neiguan" (PC 6) at Different Frequencies on Plasma Vasoactive Substance Levels in Myocardial Ischemic Reperfusion Rats].

ABSTRACT

OBJECTIVE: To observe the effect of electroacupuncture (EA) stimulation of "Neiguan" (PC 6) at different frequencies on plasma vasoactive substance levels in myocardial ischemia-reperfusion (MIR) injury rats, so as to explore its mechanisms underlying improvement of acute myocardial ischemia. METHODS: A total of 40 Wistar rats were randomized into control, model, high frequency (HF, 120 Hz) and low frequency (LF, 20 Hz) groups (n = 10 in each group). The MIR model was established by occlusion of the anterior descending branch (ADB) of the left coronary artery for 30 min, followed by reperfusion for 40 min. EA (3 V, 120 Hz or 20 Hz) was applied to bilateral "Neiguan" (PC 6) for 50 min immediately after occlusion of ADB. Subsequently, the contents of plasma endothelin (ET), atrial natriuretic peptide (ANP), thromboxane B 2 (TXB2) and 6-Keto-PGF1, were assayed by radioimmunoassay, and the content of serum nitric oxide (NO) was detected by nitrate reductase method. RESULTS: Compared with the control group, the contents of plasma ET, ANP and TXB2 in the model group were significantly increased (P < 0.05), and that of plasma 6-Keto-PGF1α in the model group was notably decreased (P < 0.05), but no significant change was found in serum NO level (P > 0.05). Compared with the model group, the contents of plasma ET, ANP and TXB2 were considerably decreased, and plasma 6-Keto-PGF1α and serum NO contents were obviously increased in both HF and LF groups (P < 0.05). No significant differences were found between the HF and LF groups in plasma ET , ANP, TXB2 and 6-Keto-PGF1α contents (P > 0.05), but the HF EA was markedly superior to the LF EA in up-regulating the content of serum NO (P < 0.05). CONCLUSION: EA stimulation of "Neiguan" (PC 6) can down-regulate the contents of plasma ET, ANP and TXB2 and up-regulate contents of plasma 6-Keto-PGF1α and serum NO in MIR rats, which may contribute to its effect in relieving acute ischemic myocardial injury. The effect of HF EA is better than LF EA in raising blood NO level.