Nitric oxide and renal effects of volume expansion in conscious monkeys

1997 ◽  
Vol 272 (4) ◽  
pp. R1033-R1038 ◽  
Author(s):  
T. V. Peterson ◽  
A. B. Carter ◽  
R. A. Miller

Experiments were performed to determine the effects of nitric oxide (NO) synthase inhibition on the renal responses to volume expansion in conscious cynomolgus monkeys. All animals were volume expanded with 3% dextran in normal saline under three conditions: 1) during a control state, 2) during constant infusion of the NO synthase inhibitor N(G)-nitro-L-arginine methyl ester (L-NAME, 30 microg x kg(-1) x min(-1)), and 3) during simultaneous infusion of L-NAME and excess NO substrate L-arginine (0.6 mg x kg(-1) x min(-1)). The control volume expansion increased urine flow from 0.27 +/- 0.05 to 0.94 +/- 0.28 ml/min and sodium excretion from 21 +/- 9 to 95 +/- 26 microeq/min. During L-NAME infusion, these responses were attenuated in that urine flow only increased from 0.13 +/- 0.03 to 0.28 +/- 0.09 ml/min and sodium excretion from 13 +/- 8 to 35 +/- 23 microeq/min. Addition of L-arginine to the L-NAME infusion abolished these renal excretory effects of L-NAME alone. With combined L-NAME/L-arginine, volume expansion increased urine flow from 0.37 +/- 0.23 to 1.09 +/- 0.23 ml/min and sodium excretion from 38 +/- 27 to 150 +/- 24 microeq/min, responses similar to control. L-Arginine also markedly attenuated the effect of L-NAME to increase mean arterial pressure and abolished the L-NAME decreases in creatinine and p-aminohippurate clearances. However, an L-NAME-induced bradycardia could only be partially reversed. These results demonstrate that a functioning NO system may be important in mediating normal renal responses to volume expansion in this primate species.

2001 ◽  
Vol 281 (2) ◽  
pp. R584-R590 ◽  
Author(s):  
Thomas V. Peterson ◽  
Claus Emmeluth ◽  
Peter Bie

The renal effects of the nitric oxide (NO) synthase inhibitor nitro-l-arginine methyl ester (l-NAME) were investigated in conscious dogs undergoing sustained water diuresis and replacement of urinary sodium losses. Experiments were performed with and without additional extracellular volume expansion (isotonic saline, 2% body wt). l-NAME (10 μg · kg−1 · min−1) infused during water diuresis decreased urine flow (2.5 ± 0.2 to 1.5 ± 0.3 ml/min), free water clearance (1.9 ± 0.2 to 1.0 ± 0.2 ml/min), and sodium excretion (4.0 ± 1.7 to 2.1 ± 0.6 μmol/min). Arterial blood pressure increased from 112 ± 2 to 126 ± 3 mmHg, but creatinine clearance did not measurably change. Plasma endothelin and vasopressin concentrations and plasma renin activity (PRA) were unchanged. Urinary endothelin concentration increased (3.4 ± 0.8 to 6.2 ± 1.7 pg/ml), but the excretion rate remained constant. l-Arginine infusion (0.6 mg · kg−1 · min−1) along withl-NAME abolished the renal effects but not the blood pressure increase. Volume expansion increased urine flow (2.5 ± 0.4 to 5.7 ± 0.5 ml/min) and sodium excretion (3.8 ± 1.6 to 76.5 ± 14.5 μmol/min). l-NAME attenuated the renal effects of volume expansion: urine flow increased to 2.8 ± 0.7 ml/min and sodium excretion to 34 ± 17 μmol/min. PRA decreased with control volume expansion but not during l-NAME. Urinary endothelin levels were elevated by l-NAME, decreased with volume expansion in all series, but excretion rate remained constant. Infusion of l-arginine partially reversed these effects of l-NAME. The results demonstrate that NO synthase inhibition increases blood pressure and blunts the renal responses to water and saline loading.


1991 ◽  
Vol 261 (3) ◽  
pp. R712-R718 ◽  
Author(s):  
D. W. Zeigler ◽  
K. P. Patel

The purpose of this study was to determine if the reflex response to a saline load is altered in the obese Zucker rat. The obese Zucker rat is a genetic model of obesity and insulin-resistant diabetes that has been reported to have high blood pressure. We examined the reflux renal responses to volume expansion in both anesthetized obese and lean Zucker rats. Initial blood pressure was significantly elevated in the obese Zucker rats compared with the lean controls. Urine flow and sodium excretion from innervated and denervated kidneys were measured before and after volume expansion with normal saline. Volume expansion resulted in significantly less urine flow and sodium excretion in the obese than the lean Zucker rats. This response was evident in both the intact and denervated kidneys. Rats were then infused with atrial natriuretic peptide (ANP) to determine if natriuretic and diuretic responses were altered in these rats. The diuretic action of ANP was not significantly reduced in the obese Zucker rat. However, the natriuretic action of ANP was significantly attenuated in the obese rats. These results indicate that the reflux response to an acute saline load is attenuated in the obese Zucker rat and that this decreased response may be due to a reduction in the direct action of ANP on the kidney.


1988 ◽  
Vol 254 (6) ◽  
pp. F780-F786
Author(s):  
R. Pichet ◽  
J. Gutkowska ◽  
M. Cantin ◽  
M. Lavallee

Hemodynamic responses, renal function, and plasma levels of immunoreactive atrial natriuretic factor (irANF) were examined following volume expansion (VE) in normal (N) conscious dogs and in conscious dogs with cardiac denervation (CD). Base-line urine flow was consistently greater (P less than 0.05) in dogs with CD (0.54 +/- 0.06 ml/min) than in N (0.29 +/- 0.03 ml/min) dogs but sodium excretion did not differ between N (2.80 +/- 0.58 mu eq.min-1.kg body wt-1) and CD (3.53 +/- 0.75 mu eq.min-1.kg-1) groups. With VE (18 ml/kg of 3% dextran in saline), mean arterial pressure (MAP) increased (P less than 0.01) by 16 +/- 3 from 103 +/- 4 mmHg in N dogs but did not change from pre-VE base line (103 +/- 2 mmHg) in dogs with CD. At 10 min after VE, urine flow increased more (P less than 0.01) in N dogs (1.39 +/- 0.24 ml/min) than in dogs with CD (0.26 +/- 0.09 ml/min). At that time, increases in sodium excretion were also greater (P less than 0.01) in N (9.13 +/- 1.96 mu eq.min-1.kg-1) dogs than in dogs with CD (1.06 +/- 0.68 mu eq.min-1.kg-1). With VE, increases in irANF plasma levels were not different in N dogs (40 +/- 12 from 34 +/- 5 pg/ml) and in dogs with CD (27 +/- 3 from 45 +/- 7 pg/ml). In dogs with CD, when MAP was increased by aortic constriction to mimic responses observed in N dogs, renal responses were similar to those of N dogs.(ABSTRACT TRUNCATEDAT 250 WORDS)


2010 ◽  
Vol 299 (1) ◽  
pp. F217-F224 ◽  
Author(s):  
Mohd Shahid ◽  
Joseph Francis ◽  
Khalid Matrougui ◽  
Dewan S. A. Majid

Systemic infusion of TNF-α exerts renal vasoconstriction but caused marked natriuresis in mice. Similar renal responses were also observed during systemic infusion of nitric oxide (NO) synthase inhibitors as opposed to their usual antinatriuretic responses when administered intrarenally. In the present study, we examined the hypothesis that acute NO blockade systemically induces TNF-α generation. which induces this natriuretic response. Renal responses to intravenous infusion of the NO synthase inhibitor nitro-l-arginine methyl ester (l-NAME; 0.2 μg·min−1·g body wt−1 for 85 min) and its impact on the plasma level of TNF-α were evaluated in anesthetized mice. Plasma TNF-α was undetected in untreated mice ( n = 7) but was elevated in l-NAME-treated mice (109 ± 22 pg/ml; P < 0.01 vs. untreated group; n = 7) along with an increase in TNF-α protein expression in kidney tissue. l-NAME infusion caused a usual increase in mean arterial pressure (MAP; 98 ± 3 to 122 ± 3 mmHg; P < 0.01) and decreases in renal blood flow (RBF; 8.6 ± 0.3 to 4.4 ± 0.2 ml·min−1·g−1; P < 0.01) and glomerular filtration rate (GFR; 1.14 ± 0.07 to 0.77 ± 0.04 ml·min−1·g−1; P < 0.01) with a marked increase in sodium excretion (UNaV; 0.48 ± 0.10 to 3.52 ± 0.85 μmol·min−1·g−1; P < 0.01). Interestingly, in mice ( n = 7) pretreated with the TNF-α blocker etanercept (5 mg/kg sc), the UNaV response to l-NAME infusion was markedly blunted (0.58 ± 0.08 to 1.22 ± 0.28 μmol·min−1·g−1; P = NS) although responses for MAP, RBF, and GFR were mostly unchanged. However, pretreatment with the superoxide scavenger tempol in mice ( n = 7) did not alter the UNaV response to l-NAME. These data demonstrate that l-NAME-induced natriuresis is mediated, at least in part, by concomitant generation of TNF-α during NO blockade.


1988 ◽  
Vol 254 (5) ◽  
pp. R727-R729
Author(s):  
J. P. Gilmore ◽  
K. G. Cornish ◽  
M. W. Barazanji

We determined the influence of pentobarbital sodium on the renal responses of the monkey to acute intravascular volume expansion. Before volume expansion, the anesthetized animals had a significantly lower blood pressure and creatinine clearance and a significantly higher urine flow and sodium excretion than the conscious animals. After volume expansion with an isotonic, isoncotic, dextran solution, sodium excretion and urine flow increased significantly in both groups of animals. However, both responses were significantly greater in the anesthetized animals. The greater natriuresis in the anesthetized animals was associated with a greater fractional sodium excretion than in the conscious animals. The potentiated response of the anesthetized animal may be the result of a direct renal tubular effect of pentobarbital and/or the result of the anesthetic removing an inhibitory influence on sodium excretion.


2004 ◽  
Vol 287 (1) ◽  
pp. R27-R32 ◽  
Author(s):  
Dewan S. A. Majid ◽  
Akira Nishiyama ◽  
Keith E. Jackson ◽  
Alexander Castillo

To evaluate the role of a potential interaction between superoxide anion (O2−) and nitric oxide (NO) in regulating kidney function, we examined the renal responses to intra-arterial infusion of a superoxide dismutase mimetic, tempol (0.5 mg·kg−1·min−1), in anesthetized dogs treated with or without NO synthase inhibitor, Nω-nitro-l-arginine (NLA; 50 μg·kg−1·min−1). In one group of dogs ( n = 10), tempol infusion alone for 30 min before NLA infusion did not cause any significant changes in renal blood flow (RBF; 5.2 ± 0.4 to 5.0 ± 0.4 ml·min−1·g−1), glomerular filtration rate (GFR; 0.79 ± 0.04 to 0.77 ± 0.04 ml·min−1·g−1), urine flow (V; 13.6 ± 2.1 to 13.9 ± 2.5 μl·min−1·g−1), or sodium excretion (UNaV; 2.4 ± 0.3 to 2.2 ± 0.3 μmol·min−1·g−1). Interestingly, when tempol was infused in another group of dogs ( n = 12) pretreated with NLA, it caused increases in V (4.4 ± 0.4 to 9.7 ± 1.4 μl·min−1·g−1) and in UNaV (0.7 ± 0.1 to 1.3 ± 0.2 μmol·min−1·g−1) without affecting RBF or GFR. Although NO inhibition caused usual qualitative responses in both groups of dogs, the antidiuretic (47 ± 5 vs. 26 ± 4%) and antinatriuretic (67 ± 4 vs. 45 ± 11%) responses to NLA were seen much less in dogs pretreated with tempol. NLA infusion alone increased urinary excretion of 8-isoprostane (13.9 ± 2.7 to 22.8 ± 3.6 pg·min−1·g−1; n = 7), which returned to the control levels (11.6 ± 3.4 pg·min−1·g−1) during coadministration of tempol. These data suggest that NO synthase inhibition causes enhancement of endogenous O2− levels and support the hypothesis that NO plays a protective role against the actions of O2− in the kidney.


2003 ◽  
Vol 285 (4) ◽  
pp. H1738-H1746 ◽  
Author(s):  
Yi-Fan Li ◽  
William G. Mayhan ◽  
Kaushik P. Patel

Acute volume expansion (VE) produces a suppression of renal sympathetic nerve discharge (RSND) resulting in diuresis and natriuresis. Recently, we have demonstrated that the endogenous nitric oxide (NO) system within the paraventricular nucleus (PVN) produces a decrease in RSND. We hypothesized that endogenous NO in the PVN is involved in the suppression of RSND leading to diuretic and natriuretic responses to acute VE. To test this hypothesis, we first measured the VE-induced increase in renal sodium excretion and urine flow with and without blockade of NO, with microinjection of NG-monomethyl-l-arginine (l-NMMA; 200 pmol in 200 nl), within the PVN of Inactin-anesthetized male Sprague-Dawley rats. Acute VE produced significant increases in urine flow and sodium excretion, which were diminished in rats treated with l-NMMA within the PVN. This effect of NO blockade within the PVN on VE-induced diuresis and natriuresis was abolished by renal denervation. Consistent with these data, acute VE induced a decrease in RSND (52% of the baseline level), which was significantly blunted by prior administration of l-NMMA into the PVN (28% of the baseline level) induced by a comparable level of acute VE. Using the push-pull perfusion technique, we found that acute VE induced a significant increase in NOx concentration in the perfusate from the PVN region. Taken together, these results suggest that acute VE induces an increase in NO production within the PVN that leads to renal sympathoinhibition, resulting in diuresis and natriuresis. We conclude that NO within the PVN plays an important role in regulation of sodium and water excretions in the volume reflex via modulating renal sympathetic outflow.


2002 ◽  
Vol 282 (4) ◽  
pp. R1149-R1155 ◽  
Author(s):  
Jens Lundbæk Andersen ◽  
Niels C. F. Sandgaard ◽  
Peter Bie

The responses to infusion of nitric oxide synthase substrate (l-arginine 3 mg · kg−1 · min−1) and to slow volume expansion (saline 35 ml/kg for 90 min) alone and in combination were investigated in separate experiments. l-Arginine left blood pressure and plasma ANG II unaffected but decreased heart rate (6 ± 2 beats/min) and urine osmolality, increased glomerular filtration rate (GFR) transiently, and caused sustained increases in sodium excretion (fourfold) and urine flow (0.2 ± 0.0 to 0.7 ± 0.1 ml/min). Volume expansion increased arterial blood pressure (102 ± 3 to 114 ± 3 mmHg), elevated GFR persistently by 24%, and enhanced sodium excretion to a peak of 251 ± 31 μmol/min, together with marked increases in urine flow, osmolar and free water clearances, whereas plasma ANG II decreased (8.1 ± 1.7 to 1.6 ± 0.3 pg/ml). Combined volume expansion and l-arginine infusion tended to increase arterial blood pressure and increased GFR by 31%, whereas peak sodium excretion was enhanced to 335 ± 23 μmol/min at plasma ANG II levels of 3.0 ± 1.1 pg/ml; urine flow and osmolar clearance were increased at constant free water clearance. In conclusion, l-arginine 1) increases sodium excretion, 2) decreases basal urine osmolality, 3) exaggerates the natriuretic response to volume expansion by an average of 50% without persistent changes in GFR, and 4) abolishes the increase in free water clearance normally occurring during volume expansion. Thus l-arginine is a natriuretic substance compatible with a role of nitric oxide in sodium homeostasis, possibly by offsetting/shifting the renal response to sodium excess.


1988 ◽  
Vol 255 (3) ◽  
pp. R388-R394 ◽  
Author(s):  
T. V. Peterson ◽  
B. A. Benjamin ◽  
N. L. Hurst

Experiments were performed in conscious macaque monkeys to determine the effect of renal denervation on the diuresis and natriuresis of blood volume expansion. When the kidneys were innervated, expansion of estimated blood volume by 20% with 3% dextran in isotonic saline caused increases in urine flow (V), from 0.28 +/- 0.07 ml/min to a peak response of 1.08 +/- 0.20 ml/min, absolute sodium excretion (UNaV), from 30.0 +/- 11.2 to 99.8 +/- 11.7 mueq/min, and fractional sodium excretion (FENa+), from 1.24 +/- 0.51 to 3.19 +/- 0.56%. The animals then underwent bilateral renal denervation and were volume expanded a second time 6-13 days postdenervation. Under this condition, V increased from 0.32 +/- 0.05 to 0.64 +/- 0.08 ml/min, UNaV, from 22.2 +/- 4.6 to 46.2 +/- 8.0 mueq/min, and FENa+, from 0.91 +/- 0.26 to 1.92 +/- 0.41%, these increases being significantly less than when the kidneys were innervated. These results demonstrate that the renal nerves play an important role in the nonhuman primate in mediating increases in renal excretion during hypervolemia.


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