MacLaughlin M, de Mello Aires M, Malnic G
Ren Physiol. 1985;8(2):112-9. doi: 10.1159/000173042.
The effect of verapamil, a Ca++ antagonist drug, on renal function and proximal fluid reabsorption in normal and hypertensive (GII) rats was studied. During intravenous infusion of verapamil, mean arterial pressure (MAP) fell significantly in both groups, 23% more in hypertensive than in normotensive rats. Glomerular filtration rate (GFR) was significantly higher in hypertensive rats and also increased significantly in this group during verapamil infusion. Effective renal plasma flow (ERPF) was similar in both groups and did not change significantly during verapamil infusion. The increase in urine flow, Na+ and Ca++ excretion was higher in hypertensive than in normotensive rats during verapamil infusion. When 10(-5) M verapamil was added to the luminal perfusate of proximal tubules, fluid reabsorption was reduced to 64% in normotensive and to 42% in hypertensive rats. When added to capillary perfusate, fluid reabsorption was almost completely but reversibly inhibited (92% in normotensive and 83% in hypertensive rats). Our findings indicate a direct effect of verapamil on renal Na+ and possibly also on Ca++ reabsorption, suggesting involvement of the Na+-Ca++ countertransport system. The greater effect of verapamil on Na+ excretion in hypertensive rats was not due to increased action on proximal Na+ reabsorption.
研究了钙拮抗剂维拉帕米对正常大鼠和高血压（GII）大鼠肾功能及近端小管液体重吸收的影响。静脉输注维拉帕米期间，两组大鼠的平均动脉压（MAP）均显著下降，高血压大鼠下降幅度比正常血压大鼠多23%。高血压大鼠的肾小球滤过率（GFR）显著更高，且在输注维拉帕米期间该组GFR也显著增加。两组的有效肾血浆流量（ERPF）相似，在输注维拉帕米期间无显著变化。输注维拉帕米期间，高血压大鼠的尿流量、钠和钙排泄量增加幅度高于正常血压大鼠。当向近端小管的管腔灌流液中加入10⁻⁵ M维拉帕米时，正常血压大鼠的液体重吸收减少至64%，高血压大鼠减少至42%。当加入到毛细血管灌流液中时，液体重吸收几乎完全但可逆地受到抑制（正常血压大鼠为92%，高血压大鼠为83%）。我们的研究结果表明维拉帕米对肾脏钠重吸收有直接作用，可能对钙重吸收也有直接作用，提示钠-钙逆向转运系统参与其中。维拉帕米对高血压大鼠钠排泄的更大作用并非由于对近端钠重吸收的作用增强。
