Intrarenal Role of Angiotensin II in Controlling Sodium Excretion during Dehydration in Dogs

1977 ◽  
Vol 52 (5) ◽  
pp. 545-548 ◽  
Author(s):  
N. C. Trippodo ◽  
J. E. Hall ◽  
T. E. Lohmeier ◽  
A. C. Guyton
Keyword(s):  
Sodium Chloride ◽  
Angiotensin Ii ◽  
Sodium Excretion ◽  
Chloride Solution ◽  
Water Retention ◽  
Sodium Chloride Solution ◽  
Urinary Sodium Excretion ◽  
Urine Flow ◽  
Angiotensin Ii Antagonist

1. The intrarenal role of angiotensin II in controlling sodium excretion was examined in anaesthetized, dehydrated dogs by infusing the angiotensin II antagonist Sar1-Ile8-angiotensin II directly into the renal artery. Comparisons were made with dehydrated dogs receiving only sodium chloride solution intrarenally. 2. Intrarenal angiotensin II blockade resulted in significant increases in urinary sodium excretion and urine flow rate. 3. The results indicate that during the high-renin state of dehydration endogenous angiotensin II has intrarenal effects which lead to salt and water retention.

Excretion of Salt and Water by Patients with Sickle-Cell Anaemia: Effect of a Diuretic and Solute Diuresis

1977 ◽  
Vol 53 (6) ◽  
pp. 523-527 ◽  
Author(s):  
T. E. Forrester ◽  
G. A. O. Alleyne
Keyword(s):  
Sodium Chloride ◽  
Sickle Cell ◽  
Sodium Excretion ◽  
Chloride Solution ◽  
Sodium Chloride Solution ◽  
Sickle Cell Anaemia ◽  
Ethacrynic Acid ◽  
Free Water ◽  
Loop Of Henle ◽  
Water Reabsorption

1. Patients with sickle-cell anaemia were unable to increase free water reabsorption (TcH2O) in response to intravenous hypertonic sodium chloride solution. 2. Ethacrynic acid caused a brisk natriuresis in patients with sickle-cell anaemia but fractional sodium excretion was lower in these patients. 3. These findings could be explained by abnormal function of the loop of Henle.

Mechanisms of angiotensin II natriuresis and antinatriuresis

1985 ◽  
Vol 249 (2) ◽  
pp. F299-F307 ◽  
Author(s):  
M. E. Olsen ◽  
J. E. Hall ◽  
J. P. Montani ◽  
A. C. Guyton ◽  
H. G. Langford ◽  
...  
Keyword(s):  
Angiotensin Ii ◽  
Sodium Excretion ◽  
Distal Tubule ◽  
Urinary Sodium Excretion ◽  
Sodium Reabsorption ◽  
Ang Ii ◽  
Sodium Load ◽  
Proximal Tubular ◽  
Anesthetized Dogs

The aim of this study was to determine the role of changes in renal arterial pressure (RAP), renal hemodynamics, and tubular reabsorption in mediating the natriuretic and antinatriuretic actions of angiotensin II (ANG II). In seven anesthetized dogs, endogenous ANG II formation was blocked with captopril, and ANG II was infused intravenously at rates of 5-1,215 ng X kg-1 X min-1 while RAP was either servo-controlled at the preinfusion level or permitted to increase. When RAP was servo-controlled, ANG II infusion at all rates from 5-1,215 ng X kg-1 X min-1 decreased urinary sodium excretion (UNaV) and fractional sodium excretion (FENa) while increasing fractional reabsorption of lithium (FRLi) (an index of proximal tubular fractional sodium reabsorption) and causing no change in calculated distal tubule fractional sodium reabsorption (FRDNa). When RAP was permitted to increase, ANG II infusion rates up to 45 ng X kg-1. min-1 also decreased UNaV and FENa while increasing FRLi and causing no change in FRDNa. However, at 135 ng X kg-1 X min-1 and above, UNaV and FENa increased while FRLi and FRDNa decreased when RAP was allowed to rise, even though renal blood flow and filtration fraction were not substantially different from the values observed when RAP was servo-controlled. Filtered sodium load was slightly higher when RAP was permitted to increase during ANG II infusion compared with when RAP was servo-controlled, although the differences were not statistically significant. Thus, even very large doses of ANG II cause antinatriuresis when RAP is prevented from increasing.(ABSTRACT TRUNCATED AT 250 WORDS)

Role of atrial natriuretic peptide in volume-expansion natriuresis

1986 ◽  
Vol 251 (2) ◽  
pp. R310-R313 ◽  
Author(s):  
T. R. Schwab ◽  
B. S. Edwards ◽  
D. M. Heublein ◽  
J. C. Burnett
Keyword(s):  
Atrial Natriuretic Peptide ◽  
Sodium Excretion ◽  
Volume Expansion ◽  
Fractional Excretion ◽  
Urinary Sodium Excretion ◽  
Urine Flow ◽  
Urinary Sodium ◽  
Right Atrial ◽  
Fractional Excretion Of Sodium

Studies were performed to investigate the role of circulating atrial natriuretic peptide (ANP) in acute volume-expansion natriuresis. Sham-operated (SHAM, n = 6) and right atrial appendectomized (ATRX, n = 12) anesthetized rats underwent acute volume expansion with isoncotic albumin. After equilibration and control periods, volume expansion increased urine flow rate, urinary sodium excretion, fractional excretion of sodium, and circulating ANP. Absolute increases in urine flow rate (delta 46 +/- 4 SHAM; delta 25 +/- 5 microliter/min ATRX), urinary sodium excretion (delta 9.48 +/- 1.01 SHAM; delta 4.77 +/- 1.03 mueq/min ATRX), fractional excretion of sodium (delta 3.16 +/- 0.53 SHAM; delta 1.65 +/- 0.32% ATRX), and ANP (delta 303.3 +/- 35.9 SHAM; delta 156.6 +/- 26.0 pg/ml ATRX) were significantly reduced by right atrial appendectomy. No significant differences in mean arterial pressure, central venous pressure, or glomerular filtration rate during volume expansion were observed between groups. These studies support the hypothesis that right atrial appendectomy in the rat attenuates acute volume expansion-induced increases in circulating ANP and urinary sodium excretion and that the natriuresis of acute volume expansion is mediated in part by an increase in circulating ANP.

Activation of histamine H3 receptors inhibits renal noradrenergic neurotransmission in anesthetized dogs

2001 ◽  
Vol 280 (5) ◽  
pp. R1450-R1456 ◽  
Author(s):  
Tomoyuki Yamasaki ◽  
Isao Tamai ◽  
Yasuo Matsumura
Keyword(s):  
Receptor Antagonist ◽  
Sodium Excretion ◽  
Urinary Sodium Excretion ◽  
Urine Flow ◽  
Urinary Sodium ◽  
Renal Nerve ◽  
Anesthetized Dogs ◽  
Induced Changes ◽  
Antidiuretic Action

To investigate the possible involvement of histamine H3 receptors in renal noradrenergic neurotransmission, effects of (R)alpha-methylhistamine (R-HA), a selective H3-receptor agonist, and thioperamide (Thiop), a selective H3-receptor antagonist, on renal nerve stimulation (RNS)-induced changes in renal function and norepinephrine (NE) overflow in anesthetized dogs were examined. RNS (0.5–2.0 Hz) produced significant decreases in urine flow and urinary sodium excretion and increases in NE overflow rate (NEOR), without affecting renal hemodynamics. When R-HA (1 μg · kg−1 · min−1) was infused intravenously, mean arterial pressure and heart rate were significantly decreased, and there was a tendency to reduce basal values of urine flow and urinary sodium excretion. During R-HA infusion, RNS-induced antidiuretic action and increases in NEOR were markedly attenuated. Thiop infusion (5 μg · kg−1 · min−1) did not affect basal hemodynamic and excretory parameters. Thiop infusion caused RNS-induced antidiuretic action and increases in NEOR similar to the basal condition. When R-HA was administered concomitantly with Thiop infusion, R-HA failed to attenuate the RNS-induced antidiuretic action and increases in NEOR. However, in the presence of pyrilamine (a selective H1-receptor antagonist) or cimetidine (a selective H2-receptor antagonist) infusion, R-HA attenuated the RNS-induced actions, similarly to the case without these antagonists. Thus functional histamine H3 receptors, possibly located on renal noradrenergic nerve endings, may play the role of inhibitory modulators of renal noradrenergic neurotransmission.

Neurohypophyseal Responsiveness in the Hypertensive Rat

1956 ◽  
Vol 186 (3) ◽  
pp. 529-531
Author(s):  
Sydney M. Friedman ◽  
J. A. M. Hinke ◽  
Constance L. Friedman
Keyword(s):  
Sodium Chloride ◽  
Antidiuretic Hormone ◽  
Chloride Solution ◽  
Sodium Chloride Solution ◽  
Urine Flow ◽  
Hypertensive Rats ◽  
Hypertensive Rat ◽  
Before And After ◽  
Osmotic Stimulus

Neurohypophyseal responsiveness in normotensive and hypertensive rats was studied using a standardized intracarotid injection of a sodium chloride solution as osmotic stimulus. The response was judged by measuring the rate of urine flow before and after stimulation. Rats under DCA treatment for 3 or 6 months, as well as rats with permanent post-DCA hypertension or with spontaneous senescent hypertension were used in four separate experiments. All experiments showed the neurohypophysis of the hypertensive groups to be more responsive than its control. This is interpreted to mean that the secretion of antidiuretic hormone is inhibited and tends to accumulate in hypertension.

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