Objective: To study the protective effect and its mechanism of Shenxiong drop pills(SDP) on the acute myocardial ischemia(AMI) induced by isoprenaline(ISO). Method: Sprogue-Dawley rats were divided randomly into seven groups

with 10 in each group. They were normal group

model group

Danshen group

metoprolol group

high

medium and low-dose SDP groups(11.2

5.6

2.8 g·kg-1). The AMI rat model was established by injection with ISO. Five days later

the effect of SDP on the electrocardiogram(ECG) at different time points were observed

after the continuos administration for another two days

the activities of Na+-K+-ATPase and Ca2+-Mg2+-ATPase in myocardial tissue

the levels of endothelin-1(ET-1)

nitric oxide(NO)

thromboxane B2(TXB2)

6-keto-prostaglandin F1a(6-keto-PGF1α) and the activities of nitric oxide synthase(NOS) in serum were detected. Meanwhile

Ca2+-Mg2+-ATP enzyme

Na+-K+-ATP enzymatic activity and ATP content in rat myocardial tissues were determined. Result: SDP inhibited the J spot downward of ECG induced by ISO during myocardial ischemia

decreased the levels of ET-1

TXB2 in serum

and increased the levels of NO

6-Keto-PGFlα and the activities of NOS in serum to varying degrees

but with no significant effect on ATP content in myocardial tissues and ATP enzymatic activity. Conclusion: The SDP has the apparent protective effect on AMI injury induced by ISO

its mechanism may be correlated with protecting endothelial cell and inhibiting platelet aggregation.