Van Berlo C L, Soeters P B, Charbon G A
University Hospital Maastricht, Department of Surgery, The Netherlands.
Eur J Pharmacol. 1989 Jan 24;160(1):17-21. doi: 10.1016/0014-2999(89)90649-3.
Nifedipine is a potent vasodilator, which induces various dose-related hemodynamic responses in the gastrointestinal tract, liver and kidney. Blood flow was assessed in anesthetized dogs with non-cannulating electromagnetic flow sensors. Nifedipine was injected into a brachial vein at intervals of 2 min in graded doses from 1-16 micrograms.kg-1. The pulsatile flow and pressure signals were analog-digital converted and processed by a computer program to obtain mean flow (ml.min-1) and mean pressure (mm Hg) values for every 3 s. The vascular data are presented as conductance. The arterial pressure decreased 45% while vascular conductance in vessels of the stomach, duodenum, small and large bowel increased between 75 and 128%. No response was observed in the splenic and common hepatic artery. An increase of resistance in the hepatic artery proper, while portal flow increased suggests that there were changes in liver metabolism. Although the literature indicates a decrease in renal vascular resistance, we encountered a decrease in flow but no change in resistance. Neither did we find an increase in heart rate. We propose that small intravenous doses of nifedipine reduce the afterload of the left ventricle.
硝苯地平是一种强效血管扩张剂，可在胃肠道、肝脏和肾脏引发各种剂量相关的血流动力学反应。使用非插管式电磁流量传感器对麻醉犬的血流进行评估。硝苯地平以1 - 16微克·千克⁻¹的分级剂量，每隔2分钟经肱静脉注射。脉动血流和压力信号经模数转换后由计算机程序处理，以获取每3秒的平均血流（毫升·分钟⁻¹）和平均压力（毫米汞柱）值。血管数据以传导率表示。动脉压下降45%，而胃、十二指肠、小肠和大肠血管的血管传导率增加75%至128%。脾动脉和肝总动脉未观察到反应。肝固有动脉阻力增加，而门静脉血流增加，提示肝脏代谢发生了变化。尽管文献表明肾血管阻力降低，但我们观察到血流减少而阻力无变化。我们也未发现心率增加。我们认为小剂量静脉注射硝苯地平可降低左心室的后负荷。
