Effect of Captopril on Renal Vascular Tone in Patients with Essential Hypertension

1979 ◽  
Vol 57 (s5) ◽  
pp. 421s-423s ◽  
Author(s):  
A. Mimran ◽  
H. R. Brunner ◽  
G. A. Turini ◽  
B. Waeber ◽  
D. Brunner

1. The effect of acute inhibition of angiotensin-converting enzyme by captopril (50 mg) on renal haemodynamics and function was assessed in nine patients with essential hypertension on unrestricted sodium intake (n = 8) or low sodium diet (n = 1). 2. Captopril induced a rapid and significant decrease in arterial pressure, which was maximal within 60 min. 3. Effective renal plasma flow (ERPF) increased, glomerular filtration rate (GFR) did not change and filtration fraction (FF) decreased after captopril. No change in sodium excretion and a decrease in urinary potassium occurred. 4. In the patient on low sodium diet, captopril induced striking increases in GFR and ERPF (64 and 106% respectively). 5. The logarithm of baseline plasma renin activity was positively correlated with the change in ERPF and negatively correlated with changes in FF and renal resistance. 6. The results indicate that in patients with essential hypertension angiotensin participates actvely in the maintenance of renal vascular tone at the efferent arteriolar level. A possible influence of kinins remains to be defined.

1989 ◽  
Vol 77 (4) ◽  
pp. 389-394 ◽  
Author(s):  
Minoru Kawamura ◽  
Yuhei Kawano ◽  
Kaoru Yoshida ◽  
Masahito Imanishi ◽  
Satoshi Akabane ◽  
...  

1. Angiotensin (ANG) levels were measured in the cerebrospinal fluid of 15 patients with essential hypertension on a high sodium diet for 1 week and on a low sodium diet for a further week. ANGs were determined using a system of extraction by Sep-Pak cartridges followed by h.p.l.c. combined with radioimmunoassay. 2. Sodium depletion resulted in increases of ANG II in the cerebrospinal fluid from 1.16 ± 0.38 (sem) to 1.83 ± 0.43 fmol/ml (P < 0.01) and of ANG III from 0.65 ± 0.11 to 0.86 ± 0.15 fmol/ml (P < 0.01). 3. The ANG II level in the cerebrospinal fluid was found to be unchanged and recovery of added ANG II was approximately 90%, even after incubation for 3 h, on both diets. Thus, it is unlikely that ANG II is produced or degraded in the cerebrospinal fluid in vitro. 4. There was no significant correlation between the cerebrospinal fluid and the plasma ANG II concentration on the low sodium diet. 5. These results suggest that the cerebrospinal fluid ANG II level increases with sodium depletion, and that the effect of the level of ANG II on the activity of the angiotensin-forming system in the central nervous system may be assessed by determination of ANG II in the cerebrospinal fluid in patients with essential hypertension.


2021 ◽  
Author(s):  
Rosa D Wouda ◽  
Femke Waanders ◽  
Dick de Zeeuw ◽  
Gerjan Navis ◽  
Liffert Vogt ◽  
...  

Abstract Background Angiotensin receptor blockers (ARBs) lower blood pressure (BP) and proteinuria and reduce renal disease progression in many—but not all—patients. Reduction of dietary sodium intake improves these effects of ARBs. Dietary potassium intake affects BP and proteinuria. We set out to address the effect of potassium intake on BP and proteinuria response to losartan in non-diabetic proteinuric chronic kidney disease (CKD) patients. Methods We performed a post-hoc analysis of a placebo-controlled interventional cross-over study in 33 non-diabetic proteinuric patients (baseline mean arterial pressure and proteinuria: 105 mmHg and 3.8 g/d, respectively). Patients were treated for 6 weeks with placebo, losartan, and losartan/hydrochlorothiazide, combined with a habitual (∼200 mmol/d) and low-sodium diet (&lt;100 mmol/d), in randomized order. To analyze the effects of potassium intake, we categorized patients based on median split of 24 h urinary potassium excretion, reflecting potassium intake. Results Mean potassium intake was stable during all 6 treatment periods. Losartan and losartan/hydrochlorothiazide lowered BP and proteinuria in all treatment groups. Patients with high potassium intake showed no difference in the BP effects compared to patients with low potassium intake. The antiproteinuric response to losartan monotherapy and losartan combined with hydrochlorothiazide during the habitual sodium diet was significantly diminished in patients with high potassium intake (20% vs. 41%, p = 0.011 and 48% vs 64%, p = 0.036). These differences in antiproteinuric response abolished when shifting to the low sodium diet. Conclusions In proteinuric CKD patients, the proteinuria, but not BP-lowering response to losartan during a habitual high sodium diet was hampered during high potassium intake. Differences disappeared after sodium status change by low-sodium diet.


Circulation ◽  
2014 ◽  
Vol 130 (suppl_2) ◽  
Author(s):  
Eun Kyeung Song ◽  
Debra K Moser ◽  
Seok-Min Kang ◽  
Terry A Lennie

Background: Despite the clinical emphasis on recommending a low sodium diet (LSD), adherence to a LSD remains poor in patients with heart failure (HF). Additional research is needed to determine successful interventions to improve adherence to a LSD and health outcomes. Purpose: To determine the effect of an education intervention on adherence to a LSD and health outcomes. Method: A total of 109 HF patients (age 64±9 years, 29% female) who were non-adherent to LSD, indicating > 3g of 24-hour urinary sodium excretion (24hr UNa) at baseline, were randomly assigned to one of 3 groups: 1) symptom monitoring and restricted 3 gram sodium diet (SMART) group, 2) the telephone monitoring (TM) group, or 3) usual care control group. The SMART group received individualized teaching and guidance of self-monitoring for worsening symptom and sodium intake using symptom and food diary for 4 sessions over 8 weeks. Patients assigned to either of the 2 intervention groups (SMART or TM) received phone calls every 2 weeks over 8 weeks. At 6 months follow-up, adherence to a LSD was assessed using 24hr UNa. Patients were followed for 1 year to determine time to first event of hospitalization or death due to cardiac problems. Repeated measures ANOVA and Cox regression were used to determine the effect of intervention. Results: The SMART group (n=37) showed a significant reduction in sodium intake across time compared to the TM group (n=35) and control group (n=37) (p= .022). In the Cox regression, patients in the SMART group had longer cardiac event-free survival compared to the control group after controlling for age, gender, ejection fraction, angiotensin-converting enzyme inhibitor use, and better blocker use (p=.008). Conclusion: An education intervention focused on self-monitoring for symptom and sodium intake improved adherence to LSD and health outcomes in patients with HF. Helping patients engage in self-monitoring for symptom and sodium intake by themselves can promote better health outcome.


1989 ◽  
Vol 256 (6) ◽  
pp. E863-E871 ◽  
Author(s):  
H. Hisa ◽  
Y. H. Chen ◽  
K. J. Radke ◽  
J. L. Izzo ◽  
C. D. Sladek ◽  
...  

These experiments evaluated the contribution of alpha- and beta-adrenergic stimulation to plasma renin activity (PRA) during early and long-term dietary sodium restriction, compared with normal sodium intake. Uninephrectomized conscious dogs with catheters in the aorta, vena cava, and remaining renal artery were studied during normal sodium diet (approximately 70 meq/day), after 2-3 days of low-sodium diet (5-7 meq/day), and after greater than or equal to 2 wk of low-sodium diet. Direct renal arterial (ira) infusion of phenoxybenzamine plus propranolol decreased PRA by similar proportions (39-48%) during all three states of dietary sodium intake. The PRA achieved after adrenergic blockade remained higher (P less than 0.05) during early and long-term sodium restriction than during normal sodium intake. The effect on PRA of ira infusion of propranolol alone was not different from that of phenoxybenzamine plus propranolol during normal or low-sodium diet, and the magnitude of decrease in PRA during low-sodium diet was the same whether propranolol (1 microgram.kg-1.min-1) was infused ira or intravenously. In summary, beta-adrenergic stimulation accounts for similar proportions of PRA during early and long-term dietary sodium restriction and during normal sodium intake. Renal alpha-adrenoceptors appear to play little or no role in control of PRA under these conditions.


1984 ◽  
Vol 66 (3) ◽  
pp. 269-276 ◽  
Author(s):  
M. H. De Keijzer ◽  
A. P. Provoost ◽  
E. D. Wolff ◽  
W. J. Kort ◽  
I. M. Weijma ◽  
...  

1. In an experimental model of post-renal transplantation hypertension in rats, we studied the effect of a reduction of sodium intake on the development of this type of hypertension. 2. Systolic blood pressure, plasma- renin concentration and renal function were measured regularly in recipients of an allogeneic kidney transplant that had previously undergone active immunological enhancement. 3. Transplant recipients on a normal diet showed a rise in systolic blood pressure during the second week after transplantation. The systolic blood pressure of recipients on a low sodium diet remained normotensive throughout the 15 weeks follow-up period. 4. The plasma renin concentration was low in the hypertensive recipients on a normal diet, as compared with unilaterally nephrectomized controls. Although the plasma renin concentration of recipients on a low sodium diet fell below that of unilaterally nephrectomized controls on a low sodium diet, it was higher than that of recipients on a normal diet. 5. The renal function of transplant recipients was greatly reduced compared with that of control rats. The glomerular filtration rate was reduced to a greater extent than the effective renal plasma flow. 6. In a separate experiment it was revealed that a similar reduction in the glomerular filtration rate of kidneys permanently damaged by temporary ischaemia did not result in an increase in the systolic blood pressure. 7. Survival up to 6 weeks after transplantation was the same for both groups of recipients. Recipients on a low sodium diet, however, showed a better 15 weeks survival, probably owing to the absence of hypertension in this group. 8. The prevention of the development of hypertension by means of a reduction of sodium intake, points to an involvement of sodium retention in this post-transplantation hypertension model.


2017 ◽  
pp. 163-165 ◽  
Author(s):  
A. WALKOWSKA ◽  
M. PAWLAK ◽  
S. M. JANE ◽  
E. KOMPANOWSKA-JEZIERSKA ◽  
T. WILANOWSKI

Hypertension is a major health problem throughout the world because of its high prevalence and its association with increased risk of cardiovascular disease. Two independent studies discovered a locus conferring susceptibility to essential hypertension on chromosome 2, in the 2p25 region, but the causative gene remains unknown. Grainyhead-like 1 (GRHL1) is one of the genes located in this region. Our experiments determined that the Grhl1-null mice, when fed standard diet, have the same blood pressure as their wild type littermate controls. However, we discovered that blood pressure of these mice increases following high sodium diet and decreases when they are fed low sodium diet, and similar effects were not observed in the control wild type littermates. This suggests that the Grhl1-null mice are sensitive to the development of salt-sensitive hypertension. Thus it is possible that the GRHL1 gene is involved in the regulation of blood pressure, and it may be the causative gene for the locus of susceptibility to essential hypertension in the 2p25 region.


1957 ◽  
Vol 189 (1) ◽  
pp. 181-184 ◽  
Author(s):  
M. Jay Goodkind ◽  
Wilmot C. Ball ◽  
James O. Davis

Chronic hemorrhage in normal dogs resulted in increased urinary aldosterone-like activity and a reduction in renal sodium excretion which was approximately equivalent to the sodium content of the blood removed. Glomerular filtration rate either increased or did not change. A comparable increase in aldosterone-like activity was observed in urine from normal dogs fed a low sodium diet equivalent to the net sodium intake of dogs subjected to hemorrhage.


Hypertension ◽  
1997 ◽  
Vol 29 (3) ◽  
pp. 802-807 ◽  
Author(s):  
Guido Grassi ◽  
Bianca Maria Cattaneo ◽  
Gino Seravalle ◽  
Antonio Lanfranchi ◽  
Giambattista Bolla ◽  
...  

2013 ◽  
Vol 304 (3) ◽  
pp. R260-R266 ◽  
Author(s):  
Julie O'Neill ◽  
Alan Corbett ◽  
Edward J. Johns

Angiotensin II at the kidney regulates renal hemodynamic and excretory function, but the actions of an alternative metabolite, angiotensin (1–7), are less clear. This study investigated how manipulation of dietary sodium intake influenced the renal hemodynamic and excretory responses to intrarenal administration of angiotensin (1–7). Renal interstitial infusion of angiotensin (1–7) in anesthetized rats fed a normal salt intake had minimal effects on glomerular filtration rate but caused dose-related increases in urine flow and absolute and fractional sodium excretions ranging from 150 to 200%. In rats maintained for 2 wk on a low-sodium diet angiotensin (1–7) increased glomerular filtration rate by some 45%, but the diuretic and natriuretic responses were enhanced compared with those in rats on a normal sodium intake. By contrast, renal interstitial infusion of angiotensin (1–7) in rats maintained on a high-sodium intake had no effect on glomerular filtration rate, whereas the diuresis and natriuresis was markedly attenuated compared with those in rats fed either a normal or low-sodium diet. Plasma renin and angiotensin (1–7) were highest in the rats on the low-sodium diet and depressed in the rats on a high-sodium diet. These findings demonstrate that the renal hemodynamic and excretory responses to locally administered angiotensin (1–7) is dependent on the level of sodium intake and indirectly on the degree of activation of the renin-angiotensin system. The exact way in which angiotensin (1–7) exerts its effects may be dependent on the prevailing levels of angiotensin II and its receptor expression.


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