Key result
Verapamil pretreatment prevented the normal increases in glomerular filtration rate and effective renal plasma flow after a high-protein meal in dogs.
Why the study?
Does verapamil pretreatment prevent protein-stimulated increases in renal hemodynamics in dogs?
Does verapamil pretreatment prevent protein-stimulated increases in renal hemodynamics in dogs?
Protein-stimulated renal vasodilation requires intact voltage-dependent calcium channels, as demonstrated by verapamil's ability to prevent normal increases in renal hemodynamics after protein feeding.
No clinical implications in humans; leaves open whether calcium channel blockade modulates protein-stimulated renal hemodynamics beyond this canine model.
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.
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Woods et al. (1992) studied Healthy. Verapamil vs. No pretreatment (baseline meal response) and dopamine pretreatment was evaluated on Changes in glomerular filtration rate (GFR), effective renal plasma flow (ERPF), and sodium excretion after a meat meal. Verapamil pretreatment prevented the normal increases in glomerular filtration rate and effective renal plasma flow after a high-protein meal in dogs.
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