Impaired Autoregulatory Responses in Contralateral Kidneys of Two-Kidney, One-Clip Hypertensive Rats

1980 ◽  
Vol 59 (s6) ◽  
pp. 381s-384s ◽  
Author(s):  
D. W. Ploth ◽  
R. N. Roy ◽  
Wann-Chu Huang ◽  
L. G. Navar
Keyword(s):  
Blood Pressure ◽  
Blood Flow ◽  
Renal Blood Flow ◽  
Vascular Resistance ◽  
Urine Flow ◽  
Renal Vascular Resistance ◽  
Hypertensive Rats ◽  
Contralateral Kidney ◽  
Arterial Blood ◽  
Renal Vascular

1. Micropuncture and clearance experiments in two-kidney, one-clip renal vascular hypertensive rats examined the ability of the kidney contralateral to renal vascular stenosis to maintain renal function during conditions of reduced renal arterial blood pressure. 2. At their respective spontaneous blood pressures, renal vascular resistance was higher and glomerular filtration rate (GFR) and renal blood flow were not different in the contralateral kidneys of the hypertensive rats (170 ± 5 mmHg) compared with normal animals (129 ± 1 mmHg). Urine flow and absolute and fractional excretion of electrolyte were greater from the kidneys of the hypertensive animals. However, pressures in cortical structures were similar in the two groups. 3. As blood pressure was reduced acutely, the kidney contralateral to the renal artery stenosis achieved only small decreases in renal vascular resistance that failed to allow GFR, renal blood flow or pressures in cortical structures to be maintained. In contrast, normal rats efficiently autoregulated renal vascular resistance to allow GFR, renal blood flow and cortical pressures to be unchanged as blood pressure was altered between 130 and 115 mmHg. Urine flow and electrolyte excretion decreased to a greater extent in the hypertensive kidneys; at comparable blood pressure these indices of excretory function were not different in the two groups. 4. These observations indicate that the contralateral kidney can maintain normal haemodynamic and glomerular function only at elevated blood pressure and suggest the possibility that the impaired capacity to autoregulate renal resistances may contribute to the maintenance of hypertension observed in this model.

Renal vascular effects of epinephrine infusion in the halothane-anesthetized piglet

1994 ◽  
Vol 72 (4) ◽  
pp. 394-396 ◽  
Author(s):  
Keith J. Harrington ◽  
Robert G. Allen ◽  
Jay W. Dewald
Keyword(s):  
Blood Pressure ◽  
Blood Flow ◽  
Renal Blood Flow ◽  
Arterial Blood Pressure ◽  
Vascular Resistance ◽  
Mean Arterial Blood Pressure ◽  
Renal Vascular Resistance ◽  
Epinephrine Infusion ◽  
Arterial Blood ◽  
Renal Vascular

The objective of this study was to determine the dose–response effects of epinephrine, given by systemic intravenous infusion to the halothane-anesthetized newborn piglet, on renal blood flow, mean arterial blood pressure, and renal vascular resistance. Seven newborn piglets were acutely instrumented. A transit-time ultrasound flow probe was placed around the renal artery and a femoral arterial catheter was placed for blood pressure monitoring. Epinephrine was infused in doubling doses from 0.2 to 3.2 μg∙kg−1∙min−1. Mean arterial blood pressure increased from 54 mmHg (1 mmHg = 133.3 Pa) to an average of 96 mmHg at 3.2 μg∙kg−1∙min−1 of epinephrine. Renal blood flow increased from 165 mL∙min−1∙100 g−1 at baseline to 185 mL∙min−1∙100 g−1 at a dose of 0.2 μg∙kg−1∙min−1 and increased further at 0.4 and 0.8 μg∙kg−1∙min−1 to reach 261 mL∙min−1∙100 g−1. Renal blood flow began to fall at a dose of 3.2 μg∙kg−1∙min−1, remaining however, significantly above baseline (211 mL∙min−1∙100 g−1). Consequently, calculated renal vascular resistance fell as the dose was increased from 0.2 to 0.8 μg∙kg−1∙min−1 and then rose again at 1.6 and 3.2 μg∙kg−1∙min−1, being significantly above baseline at 3.2 μg∙kg−1∙min−1. These results demonstrate that epinephrine when given by systemic infusion to the halothane-anesthetized newborn pig is a renal vasodilator at low doses and causes renal vasoconstriction at moderate to high doses. Renal blood flow remained above baseline at all doses tested, and thus, within the dosage range tested, epinephrine infusion should not cause renal ischemia.Key words: epinephrine, kidney blood flow, piglet, renal vascular resistance.

Renal blood flow changes in contralateral kidney of Goldblatt hypertensive dog

1981 ◽  
Vol 241 (2) ◽  
pp. H145-H148
Author(s):  
B. G. Zimmerman ◽  
C. Mommsen
Keyword(s):  
Blood Flow ◽  
Renal Artery ◽  
Renal Blood Flow ◽  
Vascular Resistance ◽  
Control Level ◽  
Plasma Renin ◽  
Renal Vascular Resistance ◽  
Contralateral Kidney ◽  
Arterial Blood ◽  
Renal Vascular

Sequential changes in systemic arterial blood pressure (BP), renal blood flow (RBF) in the contralateral kidney, and plasma renin activity (PRA) were examined on conscious dogs with construction of a single renal artery (RAC). An increase of 24 mmHg in bP occurred within 2 days after RAC, and BP later plateaued at a lower level. RBF in the contralateral kidney transiently increased by 24% and then returned to the control level in 11-14 days. PRA also peaked early after RAC and then returned to control. The clamp was tightened and the renal artery was occluded (RAO) 3-20 days after RAC. BP, RBF, and PRA increased to an even greater degree than after RAC. BP peaked at 145 mmHg, and RBF increased 61.5% at 2-3 days after RAO. BP and RBF both decreased but remained above the control for the duration of the study, BP at 127 mmHg and RBF at 256 ml/min. RBF per gram for the hypertrophied contralateral kidney was calculated from the RBF before death and the weight at death. The final RBF per gram of the contralateral kidney (2.7 ml.min-1.g-1) decreased and renal vascular resistance increased compared with the estimated control RBF/g (3.7 ml.min-1.g-1) and renal vascular resistance. These results suggest that the final RBF of the contralateral kidney is not increased in proportion to its increase in weight and that it may be relatively hypoperfused in two-kidney one-clip Goldblatt hypertension.

Renal vasodilatation after inhibition of renin or converting enzyme in marmoset

1986 ◽  
Vol 251 (5) ◽  
pp. H897-H902
Author(s):  
D. Neisius ◽  
J. M. Wood ◽  
K. G. Hofbauer
Keyword(s):  
Blood Pressure ◽  
Blood Flow ◽  
Angiotensin Ii ◽  
Renal Blood Flow ◽  
Vascular Resistance ◽  
Enzyme Inhibitor ◽  
Renal Vascular Resistance ◽  
Converting Enzyme ◽  
Renin Inhibition ◽  
Renal Vascular

The relative importance of angiotensin II for the renal vasodilatory response after converting-enzyme inhibition was evaluated by a comparison of the effects of converting-enzyme and renin inhibition on renal vascular resistance. Renal, mesenteric, and hindquarter blood flows were measured with chronically implanted ultrasonic-pulsed Doppler flow probes in conscious, mildly volume-depleted marmosets after administration of a converting-enzyme inhibitor (enalaprilat, 2 mg/kg iv), a synthetic renin inhibitor (CGP 29,287, 1 mg/kg iv), or a renin-inhibitory monoclonal antibody (R-3-36-16, 0.1 mg/kg iv). Enalaprilat reduced blood pressure (-16 +/- 4 mmHg, n = 6) and induced a selective increase in renal blood flow (27 +/- 8%, n = 6). CGP 29,287 and R-3-36-16 induced comparable reductions in blood pressure (-16 +/- 4 mmHg, n = 6 and -20 +/- 4 mmHg, n = 5, respectively) and selective increases in renal blood flow (36 +/- 12%, n = 6 and 34 +/- 16%, n = 4, respectively). The decrease in renal vascular resistance was of similar magnitude for all of the inhibitors (enalaprilat -28 +/- 3%, CGP 29,287 -32 +/- 6%; and R-3-36-16 -33 +/- 7%). These results indicate that the renal vasodilatation induced after converting-enzyme or renin inhibition is mainly due to decreased formation of angiotensin II.

A perinatal nitric oxide donor increases renal vascular resistance and ameliorates hypertension and glomerular injury in adult fawn-hooded hypertensive rats

2008 ◽  
Vol 294 (6) ◽  
pp. R1847-R1855 ◽  
Author(s):  
Maarten P. Koeners ◽  
Branko Braam ◽  
Dionne M. van der Giezen ◽  
Roel Goldschmeding ◽  
Jaap A. Joles
Keyword(s):  
Nitric Oxide ◽  
Blood Pressure ◽  
Blood Flow ◽  
Vascular Resistance ◽  
Renal Injury ◽  
Renal Vascular Resistance ◽  
Perinatal Exposure ◽  
Hypertensive Rats ◽  
No Donor ◽  
Renal Vascular

Enhancing perinatal nitric oxide (NO) availability persistently reduces blood pressure in spontaneously hypertensive rats. We hypothesize that this approach can be generalized to other models of genetic hypertension, for instance those associated with renal injury. Perinatal exposure to the NO donor molsidomine was studied in fawn-hooded hypertensive (FHH) rats, a model of mild hypertension, impaired preglomerular resistance, and progressive renal injury. Perinatal molsidomine increased urinary NO metabolite excretion at 8 wk of age, i.e., 4 wk after treatment was stopped ( P < 0.05). Systolic blood pressure was persistently reduced after molsidomine (42-wk females: 118 ± 3 vs. 141 ± 5 and 36-wk males: 139 ± 4 vs. 158 ± 4 mmHg; both P < 0.001). Perinatal treatment decreased glomerular filtration rate ( P < 0.05) and renal blood flow ( P < 0.01) and increased renal vascular resistance ( P < 0.05), without affecting filtration fraction, suggesting persistently increased preglomerular resistance. At 4 wk of age natriuresis was transiently increased by molsidomine ( P < 0.05). Molsidomine decreased glomerulosclerosis ( P < 0.05). Renal blood flow correlated positively with glomerulosclerosis in control ( P < 0.001) but not in perinatally treated FHH rats. NO dependency of renal vascular resistance was increased by perinatal molsidomine. Perinatal enhancement of NO availability can ameliorate development of hypertension and renal injury in FHH rats. Paradoxically, glomerular protection by perinatal exposure to the NO donor molsidomine may be due to persistently increased preglomerular resistance. The mechanisms by which increased perinatal NO availability can persistently reprogram kidney function and ameliorate hypertension deserve further study.

Effects of volume expansion on renal nerve activity, renal blood flow, and sodium and water excretion in conscious dogs

1985 ◽  
Vol 249 (5) ◽  
pp. F680-F687 ◽  
Author(s):  
H. Morita ◽  
S. F. Vatner
Keyword(s):  
Blood Flow ◽  
Renal Blood Flow ◽  
Vascular Resistance ◽  
Volume Expansion ◽  
Renal Vascular Resistance ◽  
Conscious Dogs ◽  
Renal Nerve ◽  
Water Excretion ◽  
Renal Nerve Activity ◽  
Renal Vascular

Effects of acute volume expansion with isotonic isoncotic 3% dextran in saline were examined on renal nerve activity (RNA), renal blood flow, vascular resistance, and sodium and water excretion in conscious dogs. In intact dogs, acute volume expansion increased mean arterial pressure 15 +/- 3 mmHg, left atrial pressure 5.5 +/- 0.6 mmHg, and decreased RNA 88 +/- 2%, whereas renal blood flow did not change and renal vascular resistance increased slightly. When renal perfusion pressure was maintained at control levels, volume expansion decreased RNA 87 +/- 2% and renal vascular resistance 15 +/- 4%. During the 80-min period after volume expansion, urine flow rate increased 0.66 +/- 0.13 ml/min and sodium excretion rose 3.89 +/- 0.54 mueq X min-1 X kg-1, whereas RNA remained depressed. Arterial baroreceptor denervation (ABD) did not diminish responses of RNA, renal blood flow, renal vascular resistance, or sodium and water excretion to volume expansion. After ABD plus bilateral cervical vagotomy, volume expansion did not decrease RNA, and diuretic and natriuretic responses were significantly attenuated (P less than 0.025). However, responses of renal blood flow to volume expansion were not altered significantly. In conscious dogs with renal denervation, responses of renal blood flow to volume expansion were not impaired, whereas diuretic and natriuretic responses were attenuated (P less than 0.025). Thus, in intact conscious dogs, vagally mediated reflex decreases in RNA induced by acute volume expansion exerted a significant effect on sodium and water excretion but little control of renal blood flow and renal vascular resistance.

Limb tourniquet and intramuscular clostridial toxin effects on renal function

1962 ◽  
Vol 17 (1) ◽  
pp. 83-86 ◽  
Author(s):  
James F. Nickel ◽  
John A. Gagnon ◽  
Leonard Levine
Keyword(s):  
Blood Pressure ◽  
Vascular Resistance ◽  
Sodium Excretion ◽  
Renal Vascular Resistance ◽  
Arterial Blood ◽  
Hind Limbs ◽  
Renal Changes ◽  
Anesthetized Dogs ◽  
Peripheral Trauma ◽  
Renal Vascular

Eight anesthetized dogs, given Clostridium perfringens type A toxic filtrate into the hind-limb muscles, showed severe spreading edema, hemoconcentration, marked reduction in para-aminohippurate (PAH) and creatinine clearances, and a rise in the renal vascular resistance. In the first 4 hr sodium excretion fell sharply, and mean arterial blood pressure, slightly. In eight similar dogs venous-occlusive pneumatic tourniquets were applied high on both hind limbs for 90 min. Edema was localized and minimal. Hematocrit was unchanged. PAH and creatinine clearances were extremely low in the second 30-min period of the occlusion but had risen somewhat in the last 30-min period. Sodium excretion was greatly reduced. Arterial pressure and vascular resistance rose very significantly. Upon removal of the tourniquets, PAH and creatinine clearances, blood pressure, and renal vascular resistance returned toward normal. Sodium excretion continued to fall. In many respects the renal changes resulting from two different forms of peripheral trauma are similar. Submitted on August 14, 1959

scholarly journals Losartan does not decrease renal oxygenation and norepinephrine effects in rats after resuscitated hemorrhage

2018 ◽  
Vol 315 (2) ◽  
pp. F241-F246
Author(s):  
Sofia Jönsson ◽  
Jacqueline M. Melville ◽  
Mediha Becirovic-Agic ◽  
Michael Hultström
Keyword(s):  
Blood Flow ◽  
Mean Arterial Pressure ◽  
Arterial Pressure ◽  
Renal Blood Flow ◽  
Oxygen Tension ◽  
Vascular Resistance ◽  
Renal Vascular Resistance ◽  
Renal Oxygen Consumption ◽  
Significant Difference ◽  
Renal Vascular

Renin-angiotensin-system blockers are thought to increase the risk of acute kidney injury after surgery and hemorrhage. We found that losartan does not cause renal cortical hypoxia after hemorrhage in rats because of decreased renal vascular resistance, but we did not evaluate resuscitation. We aimed to study losartan’s effect on renal cortical and medullary oxygenation, as well as norepinephrine’s vasopressor effect in a model of resuscitated hemorrhage. After 7 days of losartan (60 mg·kg−1·day−1) or control treatment, male Wistar rats were hemorrhaged 20% of their blood volume and resuscitated with Ringerʼs acetate. Mean arterial pressure, renal blood flow, and kidney tissue oxygenation were measured at baseline and after resuscitation. Finally, the effect of norepinephrine on mean arterial pressure and renal blood flow was investigated. As expected, losartan lowered mean arterial pressure but not renal blood flow. Losartan did not affect renal oxygen consumption and oxygen tension. Mean arterial pressure and renal blood flow were lower after resuscitated hemorrhage. A smaller increase of renal vascular resistance in the losartan group translated to a smaller decrease in cortical oxygen tension, but no significant difference was seen in medullary oxygen tension, either between groups or after hemorrhage. The effect of norepinephrine on mean arterial pressure and renal blood flow was similar in control- and losartan-treated rats. Losartan does not decrease renal oxygenation after resuscitated hemorrhage because of a smaller increase in renal vascular resistance. Further, losartan does not decrease the efficiency of norepinephrine as a vasopressor, indicating that blood pressure may be managed effectively during losartan treatment.

Long-Term versus Short-Term Effects of Hydrochlorothiazide on Renal Haemodynamics in Essential Hypertension

1979 ◽  
Vol 56 (5) ◽  
pp. 463-469 ◽  
Author(s):  
P. Van Brummelen ◽  
M. Woerlee ◽  
M. A. D. H. Schalekamp
Keyword(s):  
Blood Flow ◽  
Essential Hypertension ◽  
Renal Blood Flow ◽  
Vascular Resistance ◽  
Plasma Renin ◽  
Renal Vascular Resistance ◽  
Vanillylmandelic Acid ◽  
Plasma Renin Concentration ◽  
Renal Vascular

1. Renal blood flow, glomerular filtration rate, renal vascular resistance and filtration fraction were studied in ten patients with essential hypertension, during placebo, and after 1 week, 3, 6 and 9 months of hydrochlorothiazide. Plasma renin concentration and urinary excretion of vanillylmandelic acid were also measured. 2. Mean arterial pressure was lowered significantly during hydrochlorothiazide, the long-term effect being slightly more pronounced than the short-term effect. 3. The decrease in renal blood flow during the first week (P < 0·01) was followed by a progressive rise. After 9 months renal blood flow was above placebo level in eight of the ten patients. After an initial decrease, glomerular filtration rate returned gradually to its original value. Renal vascular resistance and filtration fraction increased during the first week and declined thereafter. After 3, 6 and 9 months renal vascular resistance was significantly lower compared with placebo values. 4. Plasma renin concentration and urinary excretion of vanillylmandelic acid increased significantly during the first week of hydrochlorothiazide. Subsequently, vanillylmandelic acid fell to below pretreatment amounts (P < 0·05), whereas plasma renin concentration remained elevated. 5. Long-term treatment of essential hypertension with hydrochlorothiazide has a favourable effect on abnormal renal haemodynamics. Besides the influence of blood pressure reduction per se, humoral and neural factors may be involved.

scholarly journals Impact of Iodinated Contrast on Renal Function and Hemodynamics in Rats with Chronic Hyperglycemia and Chronic Kidney Disease

2016 ◽  
Vol 2016 ◽  
pp. 1-5 ◽  
Author(s):  
Sheila Marques Fernandes ◽  
Daniel Malisani Martins ◽  
Cassiane Dezoti da Fonseca ◽  
Mirian Watanabe ◽  
Maria de Fátima Fernandes Vattimo
Keyword(s):  
Blood Pressure ◽  
Chronic Kidney Disease ◽  
Blood Flow ◽  
Renal Function ◽  
Kidney Disease ◽  
Renal Blood Flow ◽  
Arterial Blood ◽  
Chronic Hyperglycemia ◽  
Iodinated Contrast ◽  
Renal Vascular

Iodinated contrast (IC) is clinically used in diagnostic and interventional procedures, but its use can result in contrast-induced acute kidney injury (CI-AKI). Chronic kidney disease (CKD) and chronic hyperglycemia (CH) are important predisposing factors to CI-AKI. The aim of this study was to investigate the impact of iodinated contrast on the renal function and hemodynamics in rats with chronic hyperglycemia and chronic kidney disease. A total of 30 rats were divided into six groups; Sham: control of chronic renal disease; Citrate: control of chronic hyperglycemia (CH); Nx5/6: rats with 5/6 nephrectomy; Chronic Hyperglycemia: rats receiving Streptozotocin 65 mg/kg; Nx5/6 + IC: rats Nx5/6 received 6 mL/kg of IC; CH + IC: Chronic hyperglycemia rats receiving 6 mL/kg of IC. Renal function (inulinclearance; urinary neutrophil gelatinase-associated lipocalin, NGAL) and hemodynamics (arterial blood pressure; renal blood flow; renal vascular resistance) were evaluated. Iodinated contrast significantly increased urinary NGAL and reduced inulinclearance, while the hemodynamics parameters showed changes in arterial blood pressure, renal blood flow, and renal vascular resistance in both CKD and CH groups. The results suggest that the iodinated contrast in risk factors models has important impact on renal function and hemodynamics. NGAL was confirmed to play a role of highlight in diagnosis of CI-AKI.

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