scholarly journals Exogenous and endogenous angiotensin-II decrease renal cortical oxygen tension in conscious rats by limiting renal blood flow

2016 ◽  
Vol 594 (21) ◽  
pp. 6287-6300 ◽  
Author(s):  
Tonja W. Emans ◽  
Ben J. Janssen ◽  
Maximilian I. Pinkham ◽  
Connie P. C. Ow ◽  
Roger G. Evans ◽  
...  
1978 ◽  
Vol 235 (4) ◽  
pp. F286-F290 ◽  
Author(s):  
W. S. Spielman ◽  
H. Osswald

In contrast to the postocclusive hyperemia of brain, heart, and skeletal muscle, the hemodynamic response of the kidney following renal artery occlusion is highly variable in that both hyperemia and ischemia have been reported. The present study evaluates the factors influencing the renal response to complete renal artery occlusion (5-60 s) in the anesthetized cat. Marked postocclusive vasoconstriction could only be domonstrated in meclofenamate-treated (10 mg/kg) cats. The delta% renal blood flow (RBF) (30-s occlusion) was 16 +/- 4 in controls and 54 +/- 4 after meclofenamate (n= 10; P less than 0.001). Chronic denervation of the kidney, alpha-adrenergic receptor blockade, or infusion of [Sar1, Ile8]angiotensin II(2 microgram/min per kg) did not affect the postocclusive reduction of RBF, indicating that the vasoconstriction was independent of renal nerves, catecholamines, and circulating angiotesin II. Adenosine injected into the renal artery of five cats caused a dose-dependent transient fall of RBF. A dose of 100 nmol adenosine reduced RBF by 44 +/- 6% whereas after meclofenamate only 1 nmol produced the same degree of vasoconstriction. In summary, this study demonstrates a marked potentiation of the postocclusive vasoconstrictor response and the vasoconstrictive action of adenosine by meclofenamate in the anesthetized animal. No evidence was obtained to support a role for the sympathetic nervous system or circulating angiotensin II in mediating the postocclusive vasoconstriction.


1991 ◽  
Vol 69 (4) ◽  
pp. 507-511 ◽  
Author(s):  
John C. Passmore ◽  
Agnes E. Jimenez

The effect of selective dietary sodium and (or) chloride loading on blood pressure and renal blood flow (RBF) in the rat angiotensin II (AII) model of hypertension was determined. AII (200 ng/min) or saline was infused intraperitoneally. Diets were provided with either high or low concentrations of sodium, chloride or both ions for 22 days. The blood pressure of saline-treated animals was not increased by the high sodium chloride diet. Animals on a high sodium, high chloride diet had a significantly greater increase of blood pressure at 8, 15, 18, and 22 days of AII infusion compared with AII-treated animals on a low sodium, low chloride diet (p < 0.05). Selective dietary loading of either high sodium or chloride in AII-treated rats produced no greater elevation of blood pressure than AII with the low sodium, low chloride diet. Selective high dietary chloride was associated with a lower RBF in AII- and vehicle-treated rats compared with low dietary chloride. The chloride effect on RBF was greater in AII-treated animals. In conclusion, both sodium and chloride are necessary to produce the maximum increase of blood pressure in AII animals. AII enhances the decreased RBF induced by dietary chloride.Key words: angiotensin II, sodium chloride, blood pressure.


2015 ◽  
Vol 26 (12) ◽  
pp. 2953-2962 ◽  
Author(s):  
Matthew A. Sparks ◽  
Johannes Stegbauer ◽  
Daian Chen ◽  
Jose A. Gomez ◽  
Robert C. Griffiths ◽  
...  

2002 ◽  
Vol 282 (5) ◽  
pp. R1528-R1535 ◽  
Author(s):  
N. C. F. Sandgaard ◽  
J. L. Andersen ◽  
N.-H. Holstein-Rathlou ◽  
P. Bie

We have measured total renal blood flow (TRBF) as the difference between signals from ultrasound flow probes implanted around the aorta above and below the renal arteries. The repeatability of the method was investigated by repeated, continuous infusions of angiotensin II and endothelin-1 seven times over 8 wk in the same dog. Angiotensin II decreased TRBF (350 ± 16 to 299 ± 15 ml/min), an effect completely blocked by candesartan (TRBF 377 ± 17 ml/min). Subsequent endothelin-1 infusion reduced TRBF to 268 ± 20 ml/min. Bilateral carotid occlusion (8 sessions in 3 dogs) increased arterial blood pressure by 49% and decreased TRBF by 12%, providing an increase in renal vascular resistance of 69%. Dynamic analysis showed autoregulation of renal blood flow in the frequency range <0.06–0.07 Hz, with a peak in the transfer function at 0.03 Hz. It is concluded that continuous measurement of TRBF by aortic blood flow subtraction is a practical and reliable method that allows direct comparison of excretory function and renal blood flow from two kidneys. The method also allows direct comparison between TRBF and flow in the caudal aorta.


1975 ◽  
Vol 229 (4) ◽  
pp. 983-988 ◽  
Author(s):  
PA Jose ◽  
LM Slotkoff ◽  
S Montgomery ◽  
PL Calcagno ◽  
G Eisner

The ability of the immature kidney to autoregulate blood flow was investigated. Renal blood flow was measured by electromagnetic flowmeter. In six puppies, selective blockade of the intrarenal effects of angiotensin II (AII) by [1-sarcosine, 8-alanine]angiotensin II (anti-AII) administered into the renal artery did not change renal blood flow. During selective renal AII blockade, intravenous AII raised perfusion pressure from 76 +/- 2 to 100 +/- 6 mmHg. Renal blood flow increased from 1.59 +/- 0.29 to 1.98 +/- 0.59 ml/g kidney per min, but returned to control levels within 40 s in spite of persistent arterial pressure elevation. In another group of seven puppies, renal blood flow remained constant despite reduction of renal perfusion pressure by aortic constriction to 60 mmHg. In two of these seven puppies intrarenal anti-AII did not abolish autoregulation. Autoregulation of renal blood flow occurs in the puppy and is not influenced by inhibition of angiotensin. The renin-angiotensin system does not appear to be involved in the normal regulation of renal blood flow in the puppy.


1989 ◽  
Vol 505 (2) ◽  
pp. 251-256 ◽  
Author(s):  
Rainer Rettig ◽  
Francis C. White ◽  
Morton P. Printz

2012 ◽  
Vol 150 (1-3) ◽  
pp. 285-290 ◽  
Author(s):  
Miyoko Kasai ◽  
Takashi Miyazaki ◽  
Tsuneo Takenaka ◽  
Hiroyuki Yanagisawa ◽  
Hiromichi Suzuki

1986 ◽  
Vol 251 (5) ◽  
pp. H897-H902
Author(s):  
D. Neisius ◽  
J. M. Wood ◽  
K. G. Hofbauer

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.


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