间硝苯啶与硝苯啶对急性心肌缺血大鼠左心室舒张功能的影响

结扎大鼠冠脉引起T值延长,-dP/dt_(max)和-dP/dt_(max)·LVSP~(-1)降低、LVEDP抬高等心肌舒张功能降低的改变。预先分别iv M-Nif,Nif 15μg/kg均能不同程度地改善急性缺血心肌的舒张功能,其中M-Nif作用较强。此外,iv M-Nif尚有一过性增强舒张功能的作用。

Effects of M-nifedipine and nifedipine on left ventricular relaxation during acute myocardial ischemia in rats

Hemodynamic study showed that left ventricular relaxation markedly decreased in anesthetized rats with acute myocardial ischemia.The constant of isovolumic diastolic pressure decay(T)was prolonged;-dP/dtmax,-dP/dtmax LVSP-1 were declined and LVEDP was elevated significantly.The impairment of left ventricular relaxation occurred after the onset of coronary artery occlusion and reached the peak at 30 s,then lightened gradually during 5 to 30 min and was aggravated again at 60 min.M-Nif(15μg/kg iv)caused the increase in left ventricular dilatation as assessed by a shortening of T,slowing of heart rate and apparent reduction of both-dP/dtmax and SBP.But Nif only lowered BP tempo-rarily and increased heart rate obviously.M-Nif and Nif administered 15 min prior to occlusion resulted in significant decrease in T,LVEDP and augment in-dP/dtmax and-dP/dtmax LVSP-1 when compared with NS group although the relaxation was still impaired as compared with the preischemic control values.However,the action of M-Nif was greater than that of Nif.The results suggested that M-Nif,which is more beneficial than Nif,markedly improve the left ventricular relaxation of normal and acute ischemic heart in rats.