Objective: To observe the effects of electroacupuncture (EA) stimulation of "Neiguan"(PC 6) and "Shenmen" (HT 7) on 5-hydroxytryptamine (5-HT) levels in the paraventricular nucleus (PVN) region of hypothalamus and serum in hyperlipidemia rats with acute myocardial infarction (AMI).
Methods: A total of 80 SD rats with hyperlipidemia were used in the present study. Among them, 20 rats were randomly selected to be the sham-operation group, and the rest 60 cases were used to make the AMI model by occlusion of the anterior descending branch of the left coronary artery. The 60 rats who were identified to be successful in AMI were randomly divided into model group, EA-PC 6 group and EA-HT 7 group (20 rats/group). EA (2 Hz, 2 mA) was applied to bilateral PC 6 and HT 7 for 20 min, once daily for 5 days. The contents of 5-HT of hypothalamic PVN region and serum were examined by enzyme linked immunosorbent assay (ELISA) and radioimmunoassay, respectively.
Results: Following AMI, marked myocardial injury (swelling, breakage, disappearance of local transverse striations and necrosis of myocytes) with infiltration of neutrophil granulocytes was found in the model group, while in both EA-PC 6 group and EA-HT 7 group, moderate swelling (no breakage) of fewer myocardial fibers with mild infiltration of neutrophil granulocytes was found, indicating a marked improvement of myocardial injury after EA treatment. Compared with the sham-operation group, the content of 5-HT was obviously decreased in the hypothalamic PVN region and significantly increased in serum in the model group (P < 0.01). After EA intervention, the content of 5-HT was considerably up-regulated in the hypothalamic PVN region and apparently down-regulated in serum in both EA-PC 6 and EA-HT 7 groups in comparison with the model group (P < 0.01). No significant differences were found between EA-PC 6 and EA-HT 7 groups in regulating hypothalamic and serum 5-HT levels (P > 0.05).
Conclusion: EA stimulation of both PC 6 and HT 7 can relieve acute ischemic injury of the myocardium in hyperlipidemia rats, which is probably partially related to its effect in promoting the release of 5-HT from the hypothalamic PVN region.