Magnolol, an antioxidant, has been reported to possess various protective e
ffects on the cardiovascular system. However, its effect on myocardial stun
ning has not been elucidated. The purpose of this study was to investigate
the anti-stunning effect of magnolol by evaluating the recovery of regional
myocardial function after 10-minute coronary artery occlusion in anestheti
zed, open-chest rabbits. There was no significant hemodynamic change after
intravenous infusion of magnolol. Systolic wall thickening fraction (WThF)
measured with an epicardial Doppler sensor in animals pretreated with norma
l saline and vehicle solution remained significantly depressed (60 +/- 7% a
nd 77 +/- 4% of baseline WThF, respectively) 3 hours after coronary artery
reperfusion (CAR). Pretreatment with magnolol (10(-7) and 10(-6) g/kg, intr
avenous infusion) significantly enhanced the recovery of systolic wall thic
kening fraction (98 +/- 1 and 99 +/- 4% of baseline WThF, respectively) 60
minutes after CAR. This study demonstrated that intravenous pretreatment wi
th magnolol protected myocardium against stunning.