Abstract: Objective　To explore the use of antispasmodic drugs to prevent norepinephrine- induced vasospasm. 　Methods　Sixty-four SD rats were randomly divided into 8 groups. The rats were pretreated with 7 kinds of antispasmodic drugs for 30 minutes（Prostaglandin E1, sodium nitroprusside, magnesium sulfate, papaverine, phentolamine, verapamil and lidocainehydrocloride). Normal saline was used as a control agent. Then 0.1 ml norepinephrine (1:1000) was added to trigger vasospasm. The perfusion intensity and diameter of the femoral artery and vein were monitored by a laser speckle blood flow imaging system. Spss19.0 was used to compare the perfusion difference between groups.　Results　In the control group (normal saline), local application of norepinephrine for 5 minutes reduced arterial perfusion by 91% and venous perfusion by 78%. Both sodium nitroprusside and phentolamine could prevent the vasospasm of femoral artery and vein (P<0.05); papaverine only prevented the spasm of the femoral artery, and prostaglandin E1 only prevented the spasm of the femoral vein.　Conclusions　Pretreatment with sodium nitroprusside and phentolamine can prevent norepinephrine-induced vasospasm. Sodium nitroprusside has the strongest preventive effect, followed by phentolamine.

Key words: Vasospasm, 　Antispasmodic drugs, 　Preoperative prevention