scholarly journals Augmented cyclooxygenase-2 effects on renal function during varying states of angiotensin II

2010 ◽  
Vol 299 (5) ◽  
pp. F954-F962 ◽  
Author(s):  
Torrance Green ◽  
Jorge Rodriguez ◽  
L. Gabriel Navar
Keyword(s):  
Blood Flow ◽  
Glomerular Filtration Rate ◽  
Glomerular Filtration ◽  
Plasma Flow ◽  
Sodium Excretion ◽  
Filtration Rate ◽  
Renal Plasma Flow ◽  
Ang Ii ◽  
Series Of Experiments ◽  
Cox 2

Nonsteroidal anti-inflammatory drug usage has long revealed renoprotective prostaglandin actions on the renal microvasculature during increased pressor hormone influence, but whether increased cyclooxygenase (COX)-2 expression supports prostaglandin vasodilatory influence by interfering with the actions of ANG II remains unresolved. Therefore, we tested the hypothesis that COX-2 inhibition causes hemodynamic and excretory effects that are increased in proportion to ANG II activity. In anesthetized Sprague-Dawley rats having augmented cortical COX-2 expression but different ANG II activity, we conducted renal clearance experiments during acute inhibition of COX-2 with nimesulide (NMSLD) and inhibition of COX-1 with SC-560. In one series of experiments, acute captopril [acute angiotensin-converting enzyme (ACE) inhibitor (aACEi)] was administered alone ( n = 13) or in combination with chronic captopril [chronic ACEi (cACEi)] pretreatment ( n = 19). In another series of experiments, rats were fed a normal-sodium [0.4% (NS), n = 12] or a low-sodium [0.03% (LS), n = 18] diet. NMSLD did not alter mean arterial blood pressure in any group but, in the LS and cACEi groups, decreased renal plasma flow (from 3.99 ± 0.33 to 2.85 ± 0.26 and from 4.30 ± 0.19 to 3.22 ± 0.21 ml·min−1·g−1), cortical blood flow (−12 ± 8% and −13 ± 4%), and glomerular filtration rate (from 0.88 ± 0.04 to 0.65 ± 0.05 and from 0.95 ± 0.07 to 0.70 ± 0.05 ml·min−1·g−1). In contrast, medullary blood flow (MBF) was significantly decreased by COX-2 inhibition in NS (−24 ± 5%), LS (−27 ± 8%), aACEi (−16 ± 3.8%), and cACEi (−24 ± 4.2%) groups. Absolute and fractional sodium excretion rates were unchanged by NMSLD, except in the LS group (0.75 ± 0.05 μeq/min and 0.43 ± 0.15% and 0.51 ± 0.06 μeq/min and 0.26 ± 0.10%). SC-560 did not augment the effects of NMSLD. These results demonstrate an augmented COX-2-mediated vasodilation that is not contingent on ANG II, in contrast to COX-2-mediated augmented sodium excretion, where ANG II activity is requisite. Furthermore, the COX-2 effects on MBF are not contingent on ANG II or changes in cortical microvascular responses. These results reflect COX-2 continual regulation of MBF and adaptive opposition to ANG II prohypertensinogenic effects on renal plasma flow, cortical blood flow, glomerular filtration rate, and absolute and fractional sodium excretion.

Angiotensin II modulates the intrarenal effects of atrial natriuretic peptide

1988 ◽  
Vol 255 (3) ◽  
pp. F545-F551
Author(s):  
H. M. Siragy ◽  
N. E. Lamb ◽  
C. E. Rose ◽  
M. J. Peach ◽  
R. M. Carey
Keyword(s):  
Glomerular Filtration Rate ◽  
Angiotensin Ii ◽  
Atrial Natriuretic Peptide ◽  
Glomerular Filtration ◽  
Plasma Flow ◽  
Filtration Rate ◽  
Renal Plasma Flow ◽  
Systemic Effects ◽  
Ang Ii ◽  
Renal Effects

The mechanism by which atrial natriuretic peptide (ANP) increases renal water and solute excretion is not fully understood. We studied the renal effects of ANP and angiotensin II (ANG II) separately and together in uninephrectomized conscious dogs (n = 7) in sodium metabolic balance (80 meq/day). Exogenous ANG II and ANP were without measurable systemic effects as demonstrated by absence of changes in blood pressure, plasma aldosterone concentration, and plasma renin activity. The quantity of ANG II that had significant renal effects that were without measurable systemic effects was 0.2 pmol.kg-1.min-1. Three infusion rates of ANP had significant renal effects (1, 10, and 20 pmol.kg-1.min-1). These quantities of ANP caused significant diuresis, natriuresis, kaliuresis, and increased glomerular filtration rate without significant changes in renal plasma flow. ANG II alone caused significant antidiuresis, antinatriuresis, and decreased glomerular filtration rate and renal plasma flow. When ANG II and ANP were given together, no change in urinary flow rate, urinary sodium or potassium excretion, or renal plasma flow was observed, whereas glomerular filtration rate increased. Filtration fraction increased significantly with ANG II and ANP separately and together. Intrarenal ANP prevents the ANG II-induced decrement in urinary sodium excretion and urine flow rate. ANP may play an important role in escape from the sodium-retaining action of intrarenal ANG II.

Differential effect of T-type voltage-gated Ca2+ channel disruption on renal plasma flow and glomerular filtration rate in vivo

2014 ◽  
Vol 307 (4) ◽  
pp. F445-F452 ◽  
Author(s):  
Anne D. Thuesen ◽  
Henrik Andersen ◽  
Majken Cardel ◽  
Anja Toft ◽  
Steen Walter ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Blood Flow ◽  
Glomerular Filtration Rate ◽  
Glomerular Filtration ◽  
Plasma Flow ◽  
Filtration Rate ◽  
Renal Plasma Flow ◽  
Voltage Gated

Voltage-gated Ca2+ (Cav) channels play an essential role in the regulation of renal blood flow and glomerular filtration rate (GFR). Because T-type Cav channels are differentially expressed in pre- and postglomerular vessels, it was hypothesized that they impact renal blood flow and GFR differentially. The question was addressed with the use of two T-type Cav knockout (Cav3.1−/− and Cav3.2−/−) mouse strains. Continuous recordings of blood pressure and heart rate, para-aminohippurate clearance (renal plasma flow), and inulin clearance (GFR) were performed in conscious, chronically catheterized, wild-type (WT) and Cav3.1−/− and Cav3.2−/− mice. The contractility of afferent and efferent arterioles was determined in isolated perfused blood vessels. Efferent arterioles from Cav3.2−/− mice constricted significantly more in response to a depolarization compared with WT mice. GFR was increased in Cav3.2−/− mice with no significant changes in renal plasma flow, heart rate, and blood pressure. Cav3.1−/− mice had a higher renal plasma flow compared with WT mice, whereas GFR was indistinguishable from WT mice. No difference in the concentration response to K+ was observed in isolated afferent and efferent arterioles from Cav3.1−/− mice compared with WT mice. Heart rate was significantly lower in Cav3.1−/− mice compared with WT mice with no difference in blood pressure. T-type antagonists significantly inhibited the constriction of human intrarenal arteries in response to a small depolarization. In conclusion, Cav3.2 channels support dilatation of efferent arterioles and affect GFR, whereas Cav3.1 channels in vivo contribute to renal vascular resistance. It is suggested that endothelial and nerve localization of Cav3.2 and Cav3.1, respectively, may account for the observed effects.

Effects of a kinin antagonist on renal function in rats

1990 ◽  
Vol 258 (3) ◽  
pp. F643-F648
Author(s):  
M. Nakagawa ◽  
J. M. Stewart ◽  
R. J. Vavrek ◽  
A. Nasjletti
Keyword(s):  
Renal Function ◽  
Glomerular Filtration Rate ◽  
Glomerular Filtration ◽  
Plasma Flow ◽  
Sodium Excretion ◽  
Filtration Rate ◽  
Renal Plasma Flow ◽  
Combined Treatment ◽  
Neutral Endopeptidase ◽  
Kinin Receptor

We contrasted the effects of D-Arg-Arg-Pro-Hyp-Gly-Thi-Ser-DPhe-Thi-Arg-TFA (kinin receptor antagonist), of aprotinin (kallikrein inhibitor), and of combined treatment with captopril (kininase II inhibitor) and phosphoramidon (neutral endopeptidase 24.11 inhibitor) on renal function of rats with and without 14-day deoxycorticosterone pretreatment (DOC, 25 mg.kg-1.wk-1 sc). Neither the kinin antagonist nor aprotinin affected renal function in rats with and without DOC pretreatment. Combined treatment with captopril and phosphoramidon caused in rats with and without DOC pretreatment augmentation (P less than 0.05) of kinin excretion (50-64%), glomerular filtration rate (12-11%), and sodium excretion (46-48%). In DOC-pretreated rats undergoing infusion of captopril and phosphoramidon, the superimposed administration of either the kinin antagonist or aprotinin caused the lowering of renal plasma flow, glomerular filtration rate, and sodium excretion. These effects of the kinin antagonist and aprotinin in rats infused with kininase inhibitors may be the consequence of blockade, respectively, of the renal actions and synthesis of kinins that, when in excess, elicit renal vasodilation and increase glomerular filtration rate and sodium excretion. Collectively, these observations suggest regulatory influence of kinins during conditions featuring increased renal kinin levels.

Effect of Serotonin on Renal Hemodynamics and Sodium Excretion in the Dog

1958 ◽  
Vol 193 (3) ◽  
pp. 639-643 ◽  
Author(s):  
William P. Blackmore
Keyword(s):  
Glomerular Filtration Rate ◽  
Glomerular Filtration ◽  
Plasma Flow ◽  
Sodium Excretion ◽  
Filtration Rate ◽  
Direct Action ◽  
Renal Plasma Flow ◽  
Specific Effect ◽  
Arterial Blood ◽  
Change In Mean

The effects of constant intravenous infusion of serotonin with doses of 5 and 10 µg/kg/min. on glomerular filtration rate, effective renal plasma flow, urine flow and sodium excretion were studied in trained, unanesthetized female dogs. A small but significant decrease in glomerular filtration rate associated with increased renal plasma flow occurred at the 5 µg/kg/min. dose indicating a specific effect of serotonin on the kidney. Similar changes were noted with the 10 µg/kg/min. dose plus a marked antidiuretic effect that occurred in the absence of any significant change in mean arterial blood pressure and an intact neurohypophysis indicating a direct action on water reabsorption in the kidney. Urinary sodium excretion decreased with both doses as a result of a decline in glomerular filtration rate associated with increased tubular reabsorption. These results indicate that serotonin has a specific effect on the kidney and suggest that this substance may alter the caliber of the glomerular vessels to decrease renal vascular resistance.

scholarly journals RENAL FUNCTION DURING CHRONIC ANEMIA IN MAN

Blood ◽  
1947 ◽  
Vol 2 (2) ◽  
pp. 192-202 ◽  
Author(s):  
STANLEY E. BRADLEY ◽  
GERALDINE P. BRADLEY
Keyword(s):  
Blood Flow ◽  
Renal Function ◽  
Glomerular Filtration Rate ◽  
Glomerular Filtration ◽  
Plasma Flow ◽  
Filtration Rate ◽  
Normal Values ◽  
Renal Plasma Flow ◽  
Filtration Fraction ◽  
Chronic Anemia

Abstract 1. Renal function has been studied quantitatively in 15 patients with chronic anemia, 8 of whom were proved to have pernicious anemia. In 7 the anemia was secondary to chronic blood loss, iron deficiency, paroxysmal nocturnal hemoglobinuria, and leukemia. The effective renal plasma flow and glomerular filtration rate were measured by clearance technics; and tubular function, by saturation methods (diodrast Tm and glucose Tm). 2. The effective renal plasma flow, the glomerular filtration rate, and the filtration fraction (percentage of plasma filtered at the glomerulus) were reduced slightly below the normal values in most subjects. The effective renal whole blood flow was always greatly reduced, by 46 per cent on the average in males and by 31.8 per cent in females. 3. Since arterial pressure was not significantly depressed it was concluded that renal vasoconstriction occurs in chronic anemia, possibly as a homeostatic device for the diversion of blood to tissues more sensitive to oxygen lack. The relatively small reduction of filtration fraction implies afferent and efferent arteriolar vasoconstriction with dominance by the afferent arterioles. These changes were shown to be reversible, a return to normal values paralleling the return of the blood picture to normal. 4. Diodrast Tm was reduced significantly in 9 of 10 patients while the values of glucose Tm were normal in 6 of 7 patients. The normal values for glucose Tm indicated continued operation of all glomeruli and implied the absence of shunting or of cessation of blood flow in any significant portion of the kidney. The fall in diodrast Tm, which appeared to be reversible in 2 of 4 individuals, was interpreted as evidence of intracellular dysfunction rather than destruction or inactivation of nephrons.

Renal function in high-altitude natives and in natives with chronic mountain sickness

1965 ◽  
Vol 20 (5) ◽  
pp. 1026-1027 ◽  
Author(s):  
Rodolfo Lozano ◽  
Carlos Monge C.
Keyword(s):  
Blood Flow ◽  
Glomerular Filtration Rate ◽  
Glomerular Filtration ◽  
Sea Level ◽  
Plasma Flow ◽  
Filtration Rate ◽  
Renal Plasma Flow ◽  
Filtration Fraction ◽  
Chronic Mountain Sickness ◽  
Mountain Sickness

When compared with sea-level residents, the healthy natives living at an altitude of 4,540 m show a 12% reduction in the glomerular filtration rate, a 37% reduction in effective renal plasma flow, a 12% reduction in effective renal blood flow, and an increase of 39% in the filtration fraction. The corresponding values in patients with chronic mountain sickness living at 4,300 m above sea level are: glomerular filtration rate, 32% reduction; effective renal plasma flow, 57% reduction; effective renal blood flow, 9% increase; and filtration fraction, 56% increase. The mean hematocrit values of the healthy and sick natives investigated were 59 and 79%, respectively. The possible relationships between cardiac output, hematocrit values, and renal hemodynamics are discussed. altitude stress; blood flow, kidney; glomerular filtration Submitted on October 5, 1964

Vasoregulatory hormones and the hyperfiltration of diabetes

1988 ◽  
Vol 254 (2) ◽  
pp. F202-F209
Author(s):  
N. Bank ◽  
M. A. Lahorra ◽  
H. S. Aynedjian ◽  
D. Schlondorff
Keyword(s):  
Glomerular Filtration Rate ◽  
Glomerular Filtration ◽  
Plasma Flow ◽  
Filtration Rate ◽  
Renal Plasma Flow ◽  
Insulin Dependent Diabetes Mellitus ◽  
Diabetic Rats ◽  
Dependent Diabetes Mellitus ◽  
Ang Ii ◽  
Single Nephron

The role of renal vasoregulatory hormones in the hyperfiltration of early insulin-dependent diabetes mellitus (IDDM) was studied by micropuncture methods in rats with streptozotocin-induced diabetes. Seven to ten days after streptozotocin injection, untreated diabetic rats had elevated glomerular filtration rate (GFR) and single-nephron glomerular filtration rate (SNGFR), compared with normal euvolemic rats. Infusion of indomethacin (5 mg/kg) markedly reduced urinary and proximal tubular fluid prostaglandin E2 (PGE2), but GFR and SNGFR did not change. In a second group, intrarenal infusion of aprotinin (1,000 kallikrein inhibitor units.min-1.kg-1) to inhibit kallikrein also had no effect on GFR or SNGFR. In a third group, intrarenal infusion of angiotensin II (ANG II, 0.1 microgram.min-1.kg-1) reduced GFR, renal plasma flow (RPF), SNGFR, and glomerular plasma flow rate (QA) to values close to those in normal euvolemic rats. Single-nephron filtration fraction rose significantly with ANG II, but glomerular pressure (PG) was unaltered. Tubular fluid PGE2 increased in response to ANG II. Saralasin infusion following ANG II returned GFR, RPF, SNGFR, and QA to supernormal levels, and PG fell. In chronically salt-loaded normal rats, the responses to intrarenal ANG II and saralasin were similar to those observed in the diabetic rats. We conclude that hyperfiltration in early IDDM is not dependent on intact renal PGE2 or bradykinin synthesis. The results with ANG II infusion indicate that pre- and postglomerular and glomerular contractile cells of the diabetic kidney are able to constrict in response to this hormone.

scholarly journals Endothelin induces diuresis and natriuresis in the rat by acting on proximal tubular cells through a mechanism mediated by lipoxygenase products.

1991 ◽  
Vol 2 (1) ◽  
pp. 57-69
Author(s):  
N Perico ◽  
R P Cornejo ◽  
A Benigni ◽  
B Malanchini ◽  
J R Ladny ◽  
...  
Keyword(s):  
Glomerular Filtration Rate ◽  
Atrial Natriuretic Peptide ◽  
Glomerular Filtration ◽  
Plasma Flow ◽  
Sodium Excretion ◽  
Filtration Rate ◽  
Renal Plasma Flow ◽  
Lipoxygenase Products ◽  
Natriuretic Effect

Besides being a potent renal vasoconstrictor, endothelin causes diuresis and natriuresis. At which site along the nephron and how endothelin alters water and sodium handling in the tubule remain to be clarified. It was found that endothelin (75 pmol) given as an i.v. infusion in vivo to rats caused diuresis and urinary sodium excretion to double but did not affect glomerular filtration rate and renal plasma flow. On raising the dose of endothelin to 150 pmol, a further increase in diuresis and natriuresis was found, whereas glomerular filtration rate fell 33% and renal plasma flow fell 36%; 300 pmol of endothelin reduced glomerular filtration rate by 73% and renal plasma flow by 77% but did not significantly affect diuresis and absolute sodium excretion. It did, however, increase fractional sodium excretion eightfold. Lithium clearance studies of changes in tubular handling of water and sodium indicated that infusion of 150 pmol of endothelin to rats caused a reduction in absolute (pre, 84.7 +/- 5.9; post, 47.9 +/- 6.1 microEq/min/100 g) and fractional (pre, 85.7 +/- 3.0; post, 64.7 +/- 6.4%) proximal reabsorption of sodium. Endothelin infusion (150 pmol) was not associated with any significant change in plasma atrial natriuretic peptide levels, which on average remained comparable to those in rats given the vehicle alone (49.7 +/- 8.4 versus 46.3 +/- 5.6 pg/mL). In the isolated perfused rat kidney preparation, exposure to 150 pmol of endothelin significantly increased fractional sodium excretion over preinjection values (pre, 2.2 +/- 0.2; post, 7.3 +/- 1.0%) despite a marked decrease in glomerular filtration rate and renal perfusate flow. Additional in vivo experiments showed that oral administration of the specific 5-lipoxygenase inhibitor L-651,392 to rats prevented the increase in urine flow rate (pre, 5.7 +/- 0.1; post, 6.6 +/- 0.8 microL/min), and in absolute (pre, 0.33 +/- 0.04; post, 0.37 +/- 0.05 microEq/min) and fractional (pre, 0.10 +/- 0.02; post, 0.11 +/- 0.03%) sodium excretion caused by bolus i.v. infusion of endothelin (150 pmol). Similarly, a specific leukotriene C4/D4 receptor antagonist, L-649,923, also prevented the diuretic and natriuretic effect of 150 pmol of endothelin i.v. infusion. These findings show that (1) endothelin has a diuretic and natriuretic effect that is independent of its action on renal hemodynamics; (2) this effect depends on a direct action on the proximal tubules; (3) atrial natriuretic peptide does not appear to be involved in this effect; and (4) the diuretic and natriuretic responses to endothelin are mediated by 5-lipoxygenase products.

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