The Role Of 5-HT_2A Receptor In Hyperreactivity Of Platelet And Artery During Myocardial Ischemia,Myocardial Ischemia/reperfusion

Interaction between platelets and arterial wall induced by pathogenetic factors plays an important role in the pathogenesis of coronary heart disease(CHD). A lot of vasoactive agents released from aggregated platelet contribute to thrombosis and vascular contraction, which will lead to myocardial ischemia and infarction. Studies implicated that 5-HT, when released from aggregated platelets, is extremly important in inducing platelet aggregation and coronary artery spasm. Platelet aggregated at any site of injuried artery wall, will release more 5-HT, which further in turn stimulate 5-HT_2A receptor located in platelet membrane. As a result, more platelet aggregates and a vicious cycle is formed. In physiological state, 5-HT is just a weak inducer of platelet aggregation, and this aggregation is reversible. However, the circumstance is quite different in CHD, in which platelet become more sensitive to 5-HT compared with normal. Our previous studies showed that platelet aggregation induced by 5-HT in patients with acute mycardial infarction was significantly higher than that of control, and snake venom anti-thrombosis enzyme(SVATE) could inhibit the platelet hyperreactivity incuced by 5-HT. No data were shown whether platelet 5-HT_2A receptor changed and contributed to platelet hyperreactivity in those patients. Another important role of 5-HT in CHD is that 5-HT can induce coronary arterial spasm. In patients with angina, intracoronary infusion of 5-HT with concentration only leads to normal coronary arterial dilation could induce...