尼群地平(NT)和硝苯吡啶(NF)对离体豚鼠工作心脏的作用

连续记录的豚鼠离体工作心脏100min,50min内各项指标(AF、CF、LVP、dp/dtmax、ASP和HR等)值较稳定和可靠。其后有自然衰竭趋势,-dp/dtmax最先减慢,提示心脏的自然衰竭与心室舒张功能受损有关。0.1-100nMN T和0.001—10nM有负性肌力和降低心泵的作用,且呈剂量依赖关系。NT和NF抑制AF的ID_(50),分别为15.2nM和1.03nM;+dp/dtmax的ID_(50),分别为52.4nM和3.3nM;-dp/dtmax的ID_(50),分别为56.3nM和1.6nM,两者相差15倍以上,差异显著,提示NT对心脏的抑制作用比NF弱得多。

EFFECTS OF NITRENDIPINE AND NIFEDIPINE ON THE ISOLATED, PERFUSED, WORKING GUINEA-PIG HEART

An isolated working guinea-pig heart preparation was made. All the measured indices such as AF, CF, CO, LVP, dp/dtmax, HR and Ap were observed for 100 rain. Then the spontaneous heart failure appeared. The dp/dtmax was the first to markedly decline. It was suggested that the heart failure was related to the impairment of ventricular re- laxation. The main indices (AF, CO, LVP and dp/dtmax ) were inhibited by i. a. 1-100 nM NT or 0.1-10nM NF in a dose-dependent manner. According to the measured indices of the isolated working guinea-pig hearts after NT and NF, it could be suggested that there was a significant difference between the two groups. The ID_(50) of NF which inhibited 50% of AF was 15.2nM and that of NF was 1.03nM. The ID_(50) of NT dp/dtmax and NF dp/dt- max was 52. 4nM and 3. 3nM respectively. The ID_(50) of NT-dp/dtmax and NT-dp/dtmax of NF was 56.3nM and 1.6 nM respectively. The dose of NT was 15 times less than that of NF. It was suggested that NT was much less potent than NF with respect to the inhibited effect on the isolated working guinea-pig heart.