Mosca S M, Gelpi R J, Cingolani H E
Centro de Investigaciones Cardiovasculares, Facultad de Ciencias Médicas, Universidad Nacional de La Plata, Argentina.
Acta Physiol Pharmacol Latinoam. 1987;37(4):467-77.
"In vitro" experiments in our laboratory, using coronary conductance arteries, showed that nifedipine produced selective relaxant action. The aim of the present experiments was to demonstrate if this selective vasodilating effect was also detected on coronary resistance vessels of the whole animal. The experiments were performed in anesthetized dogs. In one of the groups a dose-response curve to nifedipine was obtained. In the other group a single dose was infused to each dog. The doses used were: 0.5, 1, 5 and 10 micrograms x kg-1 x min-1. The following parameters were measured: systolic, diastolic (DAP) and mean arterial pressure (MAP); systolic, diastolic (DCF), and mean coronary blood flow; developed tension (DT), heart rate (HR) and cardiac output (CO). Diastolic coronary resistance (DCR) was calculated as the ratio of DAP and DCF. Systemic resistance (SR) was calculated as the ratio of MAP and CO. DAP, MAP, DT and HR remained unchanged with the lowest doses used (0.5 and 1 micrograms x kg-1 x min-1). DCF increased 28 +/- 7% (P less than 0.05) with 0.5 microgram x kg-1 x min-1 and 49 +/- 11% (P less than 0.05) with 1 microgram x kg-1 x min-1. CO increased 13 +/- 3% (P less than 0.05) and 20 +/- 6% (P less than 0.05) respectively. DCR decreased 31 +/- 4% (P less than 0.05) with 0.5 microgram x kg-1 x min-1 and 36 +/- 6% (P less than 0.05) with 1 microgram x kg-1 x min-1. SR decreased 19.5 +/- 5% (P less than 0.05) and 19 +/- 7% (P less than 0.05) respectively. With 5 micrograms x kg-1 x min-1 DAP, MAP and DT decreased 31 +/- 2% (P less than 0.05), 26 +/- 4% (P less than 0.05), and 15 +/- 4% (P less than 0.05) respectively. HR remained unchanged. DCF and CO increased 39 +/- 13% (P less than 0.05) and 35 +/- 11% (P less than 0.05) respectively. DCR and SR decreased 49 +/- 5% (P less than 0.05) and 43 +/- 5% (P less than 0.05) respectively. DAP, MAP and DT decreased 34 +/- 3% (P less than 0.05), 29 +/- 1% and 31 +/- 5% (P less than 0.05) respectively, with 10 micrograms x kg-1 x min-1. HR decreased 9 +/- 3% (P less than 0.05). DCF and CO remained unchanged. DCR and SR decreased 47 +/- 9% (P less than 0.05) and 36 +/- 6% (P less than 0.05) respectively.(ABSTRACT TRUNCATED AT 400 WORDS)
我们实验室使用冠状动脉传导动脉进行的“体外”实验表明，硝苯地平具有选择性舒张作用。本实验的目的是证明在完整动物的冠状阻力血管上是否也能检测到这种选择性血管舒张作用。实验在麻醉犬身上进行。在其中一组中获得了硝苯地平的剂量 - 反应曲线。在另一组中，给每只犬输注单一剂量。所用剂量为：0.5、1、5和10微克×千克⁻¹×分钟⁻¹。测量了以下参数：收缩压、舒张压（DAP）和平均动脉压（MAP）；收缩期、舒张期冠状动脉血流量（DCF）和平均冠状动脉血流量；心肌收缩张力（DT）、心率（HR）和心输出量（CO）。舒张期冠状阻力（DCR）通过DAP与DCF的比值计算得出。全身阻力（SR）通过MAP与CO的比值计算得出。使用最低剂量（0.5和1微克×千克⁻¹×分钟⁻¹）时，DAP、MAP、DT和HR保持不变。0.5微克×千克⁻¹×分钟⁻¹时DCF增加28±7%（P＜0.05），1微克×千克⁻¹×分钟⁻¹时增加49±11%（P＜0.05）。CO分别增加13±3%（P＜0.05）和20±6%（P＜0.05）。0.5微克×千克⁻¹×分钟⁻¹时DCR降低3I±4%（P＜0.05），1微克×千克⁻¹×分钟⁻¹时降低36±6%（P＜0.05）。SR分别降低19.5±5%（P＜0.05）和19±7%（P＜0.05）。5微克×千克⁻¹×分钟⁻¹时，DAP、MAP和DT分别降低31±2%（P＜0.05）、26±4%（P＜0.05）和15±4%（P＜0.05）。HR保持不变。DCF和CO分别增加39±13%（P＜0.
