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ISCHEMIC PRECONDITIONING AND EXOGENOUS L-ARGININE REDUCE INFARCT SIZE IN RABBIT HEART

DING YAN-FENG, LI YU-LONG, HO SHIU-YONG

Departnent of Physiology，Institute of Basic Medicine, Hebei Medical University，Shijiazhuang 050017)

Abstract

The effects of NO donor一L-arginine (L-arg) and ischemic preconditioning (IP)on the hemodynamics and myocardial infarct size were examined in the anesthetized rabbit subjected to myocardial ischemia- repefusion to define whether exogenous L-arg could exert a beneficial effect in this pathological model，and whether the L-arg-NOpathway was involved in the cardioprotection provided by IP. The results obtained were as follows:(1)During the course of ischemia(30 min)-reperfusion(180 min)，blood pressure，heart rate and myocardial oxygen consumption decreased progressively，and the myocardial infarct size occupied 33. 9士2. 4%of the whole left ventricle: (2)The
myocardial infarct size could be reduced to 20. 1士2. 2%(P<0. 01)by pretreatment with L-arg (300 mg/kg).This myocardial protective effect of L-arg was abolished by NO synthesis inhibitor一Nitro- L- arginine (L- NNA )，thereby indicating the involv& ment of L-arg-NO pathway.(3)IP significantly reduced the infarct size to 21 .9士2. 1%(P< 0. 01)，indicating the prominent cardioprotective effect of such an intervention. Since L-NNA showed no effect on the cardioprotection afforded by IP .

Key words: ischemia-reperfusion;ischemic preconditioning;L-arginine;nitro-L-arginine;myocardial infarct size

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Citing This Article：

DING YAN-FENG, LI YU-LONG, HO SHIU-YONG. ISCHEMIC PRECONDITIONING AND EXOGENOUS L-ARGININE REDUCE INFARCT SIZE IN RABBIT HEART. Acta Physiol Sin 1996; 48 (6): (in Chinese with English abstract).