Woods L L, Smith B E, De Young D R
Division of Nephrology and Hypertension, Oregon Health Sciences University, Portland 97201.
Am J Physiol. 1992 Dec;263(6 Pt 2):F1044-50. doi: 10.1152/ajprenal.1992.263.6.F1044.
This study was designed to test the hypothesis that the changes in renal hemodynamics that occur after a high-protein meal involve voltage-dependent calcium channels. In chronically instrumented female dogs, a 10-g/kg meal of raw beef caused plasma alpha-amino nitrogen levels to increase from 3.9 +/- 0.2 to 6.7 +/- 0.5 mg/dl after 90 min, and glomerular filtration rate (GFR) rose from 59 +/- 6 to 85 +/- 7 ml/min, effective renal plasma flow (ERPF) rose from 130 +/- 22 to 213 +/- 36 ml/min, and sodium excretion rose from 21 +/- 4 to 84 +/- 20 mu eq/min. On another day the dogs were pretreated with verapamil (0.075 mg/kg + 0.005 mg.kg-1.min-1 iv), which did not change arterial pressure significantly but increased GFR by 25 +/- 7% and ERPF by 23 +/- 5%. After a subsequent meat meal, plasma alpha-amino nitrogen increased from 4.0 +/- 0.3 to 6.6 +/- 0.1 mg/dl but GFR, ERPF, and sodium excretion did not change significantly. On the other hand, pretreatment with dopamine, which caused a similar degree of vasodilation to that caused by verapamil, did not prevent the response to a subsequent meat meal. Thus verapamil specifically prevented the normal increases in renal hemodynamics after protein feeding, suggesting that protein-stimulated renal vasodilation requires intact voltage-dependent calcium channels.
本研究旨在验证高蛋白饮食后发生的肾血流动力学变化涉及电压依赖性钙通道这一假说。在长期植入监测设备的雌性犬中，给予10 g/kg的生牛肉餐，90分钟后血浆α-氨基氮水平从3.9±0.2 mg/dl升至6.7±0.5 mg/dl，肾小球滤过率（GFR）从59±6 ml/min升至85±7 ml/min，有效肾血浆流量（ERPF）从130±22 ml/min升至213±36 ml/min，钠排泄量从21±4 μeq/min升至84±20 μeq/min。另一天，给犬预先注射维拉帕米（0.075 mg/kg + 0.005 mg·kg⁻¹·min⁻¹静脉注射），这并未显著改变动脉血压，但GFR增加了25±7%，ERPF增加了23±5%。在随后的肉餐之后，血浆α-氨基氮从4.0±0.3 mg/dl升至6.6±0.1 mg/dl，但GFR、ERPF和钠排泄量没有显著变化。另一方面，预先注射多巴胺，其引起的血管舒张程度与维拉帕米相似，但并不能阻止对随后肉餐的反应。因此，维拉帕米特异性地阻止了蛋白质喂养后肾血流动力学的正常增加，这表明蛋白质刺激的肾血管舒张需要完整的电压依赖性钙通道。
