Effect of a Calcium-Entry Blocker, Nicardipine, on Intrarenal Hemodynamics in Essential Hypertension
| Autor: | Yuhei Kawano, Toru Sanai, Shunichi Kojima, Hitoshi Abe, Terunao Ashida, Kaoru Yoshida, Masahito Imanishi, Genjiro Kimura, Minoru Kawamura, Morio Kuramochi, Hiroki Yoshimi, Fujio Deguchi, Teruo Omae |
|---|---|
| Rok vydání: | 1991 |
| Předmět: |
Male
medicine.medical_specialty Mean arterial pressure Afferent arterioles Sodium Kidney Glomerulus Nicardipine Urology Natriuresis Renal function chemistry.chemical_element Essential hypertension Renal Circulation Excretion Internal medicine medicine Humans business.industry Sodium Dietary Diet Sodium-Restricted Middle Aged medicine.disease Endocrinology medicine.anatomical_structure chemistry Nephrology Renal blood flow Hypertension Female business Glomerular Filtration Rate medicine.drug |
| Zdroj: | American Journal of Kidney Diseases. 17:47-54 |
| ISSN: | 0272-6386 |
| DOI: | 10.1016/s0272-6386(12)80250-2 |
| Popis: | The effects of a calcium-entry blocker, nicardipine, on intrarenal hemodynamics were studied in essential hypertension. A 4-week study was performed in eight patients with essential hypertension who were given a regular sodium diet in the first and third weeks, and a sodium-restricted diet in the second and fourth weeks. Nicardipine, 60 mg/d, was administered in the third and fourth weeks. The urinary sodium excretion rate (U Na V) was plotted on the y-axis against the mean arterial pressure (MAP) on the x-axis before and after the administration of nicardipine. Assuming the difference between MAP and the x-intercept of this renal function curve represents the effective filtration pressure across the glomerular capillaries, the intrarenal hemodynamics such as afferent arteriolar resistance (R A ) and efferent arteriolar resistances (R E ), glomerular pressure (P G ), and gross filtration coefficient (K FG ) were calculated. Although the MAP on regular salt diet was lowered from 125 ± 3 to 109 ± 2 mm Hg by nicardipine, neither the renal blood flow rate (RBF) (670 ± 40 mLlmin) nor the glomerular filtration rate (GFR) (79 ± 2 mLlmin) was altered. The R A was estimated to be reduced from 9,300 ± 900 to 7,400 ± 700 dyne·s·cm −5 ( P E (4,900 ± 400 dyne·s·cm −5 ), P G (50 ± 1 mm Hg), or K FG (0.180 ± 0.041 [mL/s]/mm Hg). Essential hypertension has been chararacterized by a prominent increase in R A , resulting in maintenance of normal P G . This Ca-entry blocker worked to normalize intrarenal hemodynamics in essential hypertension by dilating afferent arterioles alone. The reason why neither the RBF nor the GFR was increased by a longterm administration of nicardipine seemed due mainly to a parallel reduction in MAP with the reduced R A . |
| Databáze: | OpenAIRE |
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