Abe Y, Komori T, Miura K, Takada T, Imanishi M, Okahara T, Yamamoto K
J Cardiovasc Pharmacol. 1983 Mar-Apr;5(2):254-9. doi: 10.1097/00005344-198303000-00015.
The effects of nicardipine, classed as a calcium antagonist, on renal hemodynamics, renal function, and renin release were investigated in pentobarbital-anesthetized dogs. Intrarenal infusion of this drug at a rate of 5 micrograms/min in both hydrated and hydropenic dogs resulted in a significant increase in renal blood flow, glomerular filtration rate, urine flow, and renin release, with a significant fall in systemic blood pressure. The intrarenal blood flow as measured by the microsphere method indicated a greater increase in flow rate in the juxtamedullary than in the superficial area. During nicardipine infusion, free water reabsorption rate (TcH2O) in hydropenic dogs or free water production (CH2O) in hydrated dogs increased in proportion to the urine flow. Neither TcH2O/CH2O nor CH2O/osmolar clearance were significantly changed throughout the experiments. These data suggest that nicardipine did not inhibit sodium transport at the medullary portion of the ascending limb of Henle, and that the increase in GFR might induce an enhancement of the delivery of sodium to the Henle loop. In addition, an intrarenal hemodynamic alteration may be one possible mechanism involved in the diuretic action of nicardipine. Calcium-antagonistic actions of nicardipine may account for the changes in renal parameters.
在戊巴比妥麻醉的犬中研究了被归类为钙拮抗剂的尼卡地平对肾血流动力学、肾功能和肾素释放的影响。在水合和缺水的犬中，以5微克/分钟的速率肾内输注该药物导致肾血流量、肾小球滤过率、尿流量和肾素释放显著增加，同时全身血压显著下降。用微球法测量的肾内血流量表明，近髓质区域的流速增加幅度大于浅表区域。在输注尼卡地平期间，缺水犬的自由水重吸收率（TcH2O）或水合犬的自由水生成率（CH2O）与尿流量成比例增加。在整个实验过程中，TcH2O/CH2O和CH2O/渗透清除率均无显著变化。这些数据表明，尼卡地平并未抑制亨氏袢升支髓质部的钠转运，肾小球滤过率的增加可能导致进入亨氏袢的钠输送增加。此外，肾内血流动力学改变可能是尼卡地平利尿作用的一种可能机制。尼卡地平的钙拮抗作用可能解释了肾脏参数的变化。
