Abstract: The early changs of ischemic/repurfusion ventricular arrhythmia(VA,、the blood nitric oxide(NO)and the myocardial nitrio oxide synthetase(NOS)were observed for the study of effects of endogenous NO on ischemic/reperfusion VA. It was found that: ① the VA of myocardial ischemic/repurfusion rats(I/R)was more than(P<0.01)and NO was less than(P<0.05)the control group; there was the negative interrelationship botween NO and VA grade(r=-0.745 14 , P<0.05). It indicated that there was the relationship between the dicrease of NO and the increase of VA. ② there was no notable difference of NOS between I/R and control group. It seems to point out that the increased consumption increase leads to the dicrease of NO.

Key words: nitric oxide, nitric oxide synthetase, ischemic/repurfusion injury, vetricullar arrhythmia