Hemodynamic and renal effects of low-dose infusions of atrial peptide in awake dogs

1988 ◽  
Vol 254 (2) ◽  
pp. R161-R169 ◽  
Author(s):  
P. Bie ◽  
B. C. Wang ◽  
R. J. Leadley ◽  
K. L. Goetz
Keyword(s):  
Atrial Natriuretic Peptide ◽  
Natriuretic Peptide ◽  
Sodium Excretion ◽  
Plasma Renin ◽  
Urine Flow ◽  
Right Atrial ◽  
Experimental Protocols ◽  
Cardiac Filling ◽  
Left And Right ◽  
Atrial Natriuretic

The effects of alpha-human atrial natriuretic peptide (alpha-hANP) on cardiovascular and renal function in conscious dogs were evaluated in two experimental protocols. In one protocol, alpha-hANP was infused intravenously at increasing rates of 50, 100, and 200 ng.min-1.kg-1 (stepup infusion) during successive 20-min periods. The greatest responses occurred during the final 20-min period of the stepup infusion when the plasma concentration of immunoreactive atrial natriuretic peptide (irANP) was increased by 44-fold over preinfusion values; pressures in the aorta and both atria were decreased at this time, whereas glomerular filtration rate, urine flow, and sodium excretion were increased. In a second protocol, alpha-hANP was infused for 1 h at constant rates of either 12.5, 25, or 50 ng.min-1.kg-1; these constant infusions increased plasma irANP by 3-, 7-, and 12-fold, respectively. Each infusion rate decreased left and right atrial pressures and increased urine flow and sodium excretion. The two lowest infusion rates elevated plasma irANP to levels that would be expected to occur only during unusual physiological, or perhaps pathophysiological, conditions. The two highest infusion rates decreased plasma renin activity. Nevertheless, the accompanying maximal increases in sodium excretion were modest (41-72%). These data imply that small changes in circulating atrial peptides that presumably occur under normal physiological conditions would not have a dominant effect on the regulation of sodium excretion; the peptides may, however, play a modulatory role on sodium excretion under these conditions. It remains to be determined whether the ability of atrial peptides to lower cardiac filling pressures is of physiological significance.

Blunted natriuresis to atrial natriuretic peptide in chronic sodium-retaining disorders

1987 ◽  
Vol 252 (5) ◽  
pp. F865-F871 ◽  
Author(s):  
J. P. Koepke ◽  
G. F. DiBona
Keyword(s):  
Heart Failure ◽  
Congestive Heart Failure ◽  
Atrial Natriuretic Peptide ◽  
Natriuretic Peptide ◽  
Flow Rate ◽  
Sodium Excretion ◽  
Urinary Sodium Excretion ◽  
Urine Flow ◽  
Urine Flow Rate ◽  
Atrial Natriuretic

Renal responses to atrial natriuretic peptide were examined in conscious dogs with congestive heart failure (tricuspid insufficiency) and in conscious rats with nephrotic syndrome (adriamycin). Heart-failure dogs displayed elevated atrial pressure and heart weights, blunted natriuresis to a saline load, and ascites. Nephrotic rats displayed proteinuria, hypoproteinemia, sodium retention, and ascites. In control animals, atrial natriuretic peptide increased absolute and fractional urine flow rate and urinary sodium excretion. Although atrial natriuretic peptide increased absolute and fractional urine flow rate and urinary sodium excretion in conscious heart-failure dogs and nephrotic rats, the responses were markedly blunted. In heart-failure dogs, infusion of atrial natriuretic peptide increased plasma concentrations of norepinephrine and epinephrine. In nephrotic rats, renal denervation reversed the blunted diuretic and natriuretic responses to atrial natriuretic peptide. Mean arterial pressure, glomerular filtration rate, and p-aminohippurate clearance were affected similarly by atrial natriuretic peptide in heart-failure dogs or nephrotic rats vs. control animals. Conscious congestive heart-failure dogs and conscious nephrotic rats have blunted diuretic and natriuretic responses to atrial natriuretic peptide.

Natriuresis induced by mild hypernatremia in humans

2002 ◽  
Vol 282 (6) ◽  
pp. R1754-R1761 ◽  
Author(s):  
Lars Juel Andersen ◽  
Jens Lundbæk Andersen ◽  
Bettina Pump ◽  
Peter Bie
Keyword(s):  
Atrial Natriuretic Peptide ◽  
Natriuretic Peptide ◽  
Sodium Excretion ◽  
Sodium Intake ◽  
Plasma Renin ◽  
Sodium Concentration ◽  
Plasma Sodium ◽  
Renal Sodium Excretion ◽  
Body Fluid Volume ◽  
Atrial Natriuretic

The hypothesis that increases in plasma sodium induce natriuresis independently of changes in body fluid volume was tested in six slightly dehydrated seated subjects on controlled sodium intake (150 mmol/day). NaCl (3.85 mmol/kg) was infused intravenously over 90 min as isotonic (Iso) or as hypertonic saline (Hyper, 855 mmol/l). After Hyper, plasma sodium increased by 3% (142.0 ± 0.6 to 146.2 ± 0.5 mmol/l). During Iso a small decrease occurred (142.3 ± 0.6 to 140.3 ± 0.7 mmol/l). Iso increased estimates of plasma volume significantly more than Hyper. However, renal sodium excretion increased significantly more with Hyper (291 ± 25 vs. 199 ± 24 μmol/min). This excess was not mediated by arterial pressure, which actually decreased slightly. Creatinine clearance did not change measurably. Plasma renin activity, ANG II, and aldosterone decreased very similarly in Iso and Hyper. Plasma atrial natriuretic peptide remained unchanged, whereas plasma vasopressin increased with Hyper (1.4 ± 0.4 to 3.1 ± 0.5 pg/ml) and decreased (1.3 ± 0.4 to 0.6 ± 0.1 pg/ml) after Iso. In conclusion, the natriuretic response to Hyper was 50% larger than to Iso, indicating that renal sodium excretion may be determined partly by plasma sodium concentration. The mechanism is uncertain but appears independent of changes in blood pressure, glomerular filtration rate, the renin system, and atrial natriuretic peptide.

Atrial natriuretic peptide response to rapid atrial pacing in cardiac-denervated dogs

1989 ◽  
Vol 257 (1) ◽  
pp. R162-R167 ◽  
Author(s):  
T. D. Williams ◽  
K. P. Walsh ◽  
R. Canepa-Anson ◽  
M. I. Noble ◽  
A. J. Drake-Holland ◽  
...  
Keyword(s):  
Atrial Natriuretic Peptide ◽  
Natriuretic Peptide ◽  
Flow Rate ◽  
Free Water ◽  
Urine Flow ◽  
Urine Flow Rate ◽  
Right Atrial ◽  
Atrial Pacing ◽  
Cardiac Denervation ◽  
Atrial Natriuretic

The effects of rapid atrial pacing on central hemodynamics, plasma hormones, and renal function were investigated in eight control and nine cardiac-denervated dogs under chloralose anesthesia. Pacing at approximately 250 ppm for 60 min caused similar increases in pulmonary wedge and right atrial pressures, systemic vascular resistance, and plasma atrial natriuretic peptide (ANP) in both groups. In control dogs, pacing produced a fall in both plasma vasopressin (AVP) and plasma renin activity (PRA) and a rise in urine flow rate associated with an increase in free water but not sodium clearance. In contrast, in cardiac-denervated dogs, both plasma AVP and PRA increased during pacing; urine flow rate did not change, and marked sodium retention occurred. This study supports the concept that the increase in urine flow during rapid atrial pacing is mediated by inhibition of renin and AVP secretion through intact cardiac nerves. The secretion of ANP is unaffected by cardiac denervation. The natriuretic and vasodilator actions of high plasma ANP concentrations during rapid atrial pacing can be inhibited either by neurally mediated cardiorenal effects in normal animals or by stimulation of the renin-angiotensin system after cardiac denervation.

Atrial natriuretic peptide, right atrial pressure, and sodium excretion rate in the rat

1987 ◽  
Vol 253 (5) ◽  
pp. F969-F975 ◽  
Author(s):  
T. A. Fried ◽  
M. A. Ayon ◽  
G. McDonald ◽  
A. Lau ◽  
T. Inagami ◽  
...  
Keyword(s):  
Atrial Natriuretic Peptide ◽  
Natriuretic Peptide ◽  
Flow Rate ◽  
Sodium Excretion ◽  
Volume Expansion ◽  
Excretion Rate ◽  
Balloon Catheter ◽  
Urine Flow ◽  
Urine Flow Rate ◽  
Right Atrial

This study examined the relationship between right atrial pressure (RAP), urine flow rate, sodium excretion rate, and plasma atrial natriuretic peptide (ANP) levels after an acute Ringer expansion. Two groups of rats had their RAP monitored and balloon catheters placed in their thoracic inferior venae cavae. In one group the balloon remained deflated, and in the second group the balloon was inflated during the volume expansion in an attempt to prevent the rise in RAP. The peak RAP was 7.3 +/- 0.8 mmHg when the balloon remained deflated and 3.5 +/- 0.6 mmHg in the group with the balloon catheter inflated (P less than 0.005). The corresponding peak ANP levels were 682 +/- 140 and 223 +/- 40 pg/ml. There was a significant correlation between the peak RAP and ANP levels (r = 0.754; P less than 0.05). The inflation of the balloon catheter significantly decreased the urine flow rate and the urine sodium excretion rate. A final group of animals had 200 microliters of rabbit serum containing antibody to ANP infused before the volume expansion. The antibody-treated animals had significantly lower urine flow and sodium excretion rates than nonantibody-treated control rats. We conclude that ANP is one of the factors which allows the rat to excrete an acute Ringer expansion.

Effect of atrial natriuretic peptide on vasa recta blood flow in the rat

1987 ◽  
Vol 252 (6) ◽  
pp. F1112-F1117 ◽  
Author(s):  
B. A. Kiberd ◽  
T. S. Larson ◽  
C. R. Robertson ◽  
R. L. Jamison
Keyword(s):  
Blood Flow ◽  
Atrial Natriuretic Peptide ◽  
Natriuretic Peptide ◽  
Sodium Excretion ◽  
Urine Flow ◽  
Medullary Blood Flow ◽  
Vasa Recta ◽  
Renal Medullary Blood Flow ◽  
Experimental Group ◽  
Atrial Natriuretic

To determine whether synthetic atrial natriuretic peptide (ANP) increases renal medullary blood flow and if so whether the increase mediates the diuresis and natriuresis induced by ANP, inner medullary vasa recta blood flow in the exposed left renal papilla of anesthetized Munich Wistar rats weighing between 102 and 161 g was measured by fluorescence videomicroscopy. The rats were maintained in a euvolemic state by the infusion of albumin. Synthetic ANP (Auriculin B) was administered intravenously as 2.5 micrograms/kg body wt prime and as a continuous infusion of 0.2 microgram X min-1 X kg body wt-1 to the experimental group (n = 7). Within 2 min after ANP was given, urine flow and sodium excretion increased (29.4 +/- 3.8 to 50.4 +/- 5.8 microliter X min-1 X kidney wt-1, P less than 0.01, and 3.39 +/- 0.57 to 6.05 +/- 0.95 mueq X min-1 X g kidney wt-1, P less than 0.01, respectively), but vasa recta blood flow in descending (DVR) or ascending (AVR) vasa recta did not change significantly (9.5 +/- 2.3 to 10.0 +/- 2.8 nl/min in DVR and 5.3 +/- 1.0 to 6.1 +/- 1.2 nl/min in AVR). Forty-five minutes after ANP was begun, urine flow and sodium excretion increased further (77.1 +/- 11.1 microliter X min-1 X g kidney wt-1 and 12.0 +/- 2.15 mueq X min-1 X g kidney wt-1, respectively), and by this time vasa recta blood flow had increased significantly to 14.0 +/- 2.6 in DVR, P less than 0.01, and 9.8 +/- 1.2 in AVR, P less than 0.01.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of endogenous atrial natriuretic peptide released by rapid atrial pacing in dogs

1987 ◽  
Vol 253 (4) ◽  
pp. R599-R604 ◽  
Author(s):  
K. P. Walsh ◽  
T. D. Williams ◽  
R. Canepa-Anson ◽  
E. Pitts ◽  
S. L. Lightman ◽  
...  
Keyword(s):  
Atrial Natriuretic Peptide ◽  
Natriuretic Peptide ◽  
Plasma Concentrations ◽  
Plasma Renin ◽  
Right Atrial ◽  
Plasma Norepinephrine ◽  
Atrial Pacing ◽  
Vascular Effects ◽  
Rebound Increase ◽  
Atrial Natriuretic

The relationships between the hemodynamic, renal, and endocrine changes induced by rapid atrial pacing were studied in seven chloralose-anesthetized greyhounds paced from the right atrial appendage for 60 min at 250 beats/min. Pacing increased mean pulmonary wedge pressure, decreased cardiac output, and decreased mean arterial pressure. Systemic vascular resistance did not change significantly. Coronary sinus atrial natriuretic peptide (ANP) concentrations rose maximally within 5 min of commencing pacing. The corresponding increase in arterial ANP concentrations during this time was only 44% of its maximum value after 30 min of pacing. Plasma concentrations of arginine vasopressin were unchanged. Plasma renin activity decreased during pacing and showed a marked rebound increase at 60 min postpacing. Plasma norepinephrine levels did not change significantly during pacing. Urine flow increased during the latter 30 min of pacing. There was no significant change in sodium clearance despite high sustained concentrations of ANP. The lack of significant natriuretic and systemic vasodilator effects in association with high arterial plasma concentrations of endogenous ANP, in the absence of antagonistic mechanisms, suggests that the natriuretic and vascular effects of ANP may not be its major physiological actions.

Effect of physical exercise in hypobaric conditions on atrial natriuretic peptide secretion

1992 ◽  
Vol 263 (3) ◽  
pp. R647-R652 ◽  
Author(s):  
O. Vuolteenaho ◽  
P. Koistinen ◽  
V. Martikkala ◽  
T. Takala ◽  
J. Leppaluoto
Keyword(s):  
Atrial Natriuretic Peptide ◽  
Sea Level ◽  
Natriuretic Peptide ◽  
Plasma Renin ◽  
Amino Terminal ◽  
Significant Difference ◽  
Elimination Mechanism ◽  
Peptide Secretion ◽  
Ergometer Test ◽  
Atrial Natriuretic

To evaluate the role of atrial natriuretic peptide (ANP) in exercise-related cardiovascular and hormonal adjustments in hypobaric conditions, 14 young athletes performed a maximal ergometer test in a hypobaric chamber adjusted to simulate the altitudes of sea level and 3,000 m. Plasma immunoreactive ANP levels rose from 5.89 to 35.1 pmol/l at sea level and rose significantly less (P less than 0.05), from 5.36 to 22.3 pmol/l, at simulated 3,000 m. Plasma immunoreactive amino-terminal peptide of proANP (NT-proANP) levels increased to the same extent at sea level and at simulated 3,000 m (from 240 to 481 pmol/l and from 257 to 539 pmol/l, respectively). Plasma immunoreactive aldosterone increased significantly less at simulated 3,000 m (P less than 0.05), but the changes in plasma renin were similar in both conditions. Plasma immunoreactive endothelin-1 and serum erythropoietin levels remained unchanged. In conclusion, we found a blunted ANP response to maximal exercise of ANP in acute hypobaric exposure compared with that in normobaric conditions, but no significant difference in the NT-proANP responses between the two conditions. The divergence may be due to stimulation of the elimination mechanism of ANP.

Low-Dose Brain Natriuretic Peptide Infusion in Normal Men and the Influence of Endopeptidase Inhibition

1997 ◽  
Vol 92 (3) ◽  
pp. 255-260 ◽  
Author(s):  
C. M. Florkowski ◽  
A. M. Richards ◽  
E. A. Espiner ◽  
T. G. Yandle ◽  
E. Sybertz ◽  
...  
Keyword(s):  
Atrial Natriuretic Peptide ◽  
Plasma Renin Activity ◽  
Brain Natriuretic Peptide ◽  
Natriuretic Peptide ◽  
Low Dose ◽  
Plasma Renin ◽  
Renin Activity ◽  
Plasma Brain Natriuretic Peptide ◽  
Normal Men ◽  
Atrial Natriuretic

1. To assess the threshold dose for bioactivity of brain natriuretic peptide and the role of endopeptidase 24.11 in metabolism of brain natriuretic peptide at physiological plasma levels, we studied eight normal men receiving 2 h infusions of low-dose brain natriuretic peptide [0.25 and 0.5 pmol min−1 kg−1 with and without pretreatment with an endopeptidase inhibitor (SCH 32615, 250 mg intravenously)] in placebo-controlled studies. 2. Plasma brain natriuretic peptide increased 2-fold during the infusion of 0.25 pmol min−1 kg−1 (mean increment above control 3.9 pmol/l, P < 0.001), and tripled (P < 0.001) with 0.5 pmol min−1 kg−1. Plasma renin activity was inhibited by both doses (14.8%, P < 0.01, and 20%, P < 0.001, respectively). A significant natriuresis (56% increase in urine sodium/creatinine ratio, P < 0.02) occurred with the higher dose. Blood pressure, haematocrit, plasma cGMP, atrial natriuretic peptide and aldosterone were unaffected by either dose. 3. Compared with brain natriuretic peptide (0.5 pmol min−1 kg−1) alone, SCH 32615 pretreatment increased peak plasma brain natriuretic peptide (13.4±0.78 versus 12.4±0.86 pmol/l, P < 0.05), ANP (7.5±0.96 versus 5.9±0.4 pmol/l, P < 0.01) and cGMP (4.8 ± 1.7 versus 3.9 ± 1.4 nmol/l, P < 0.001). Plasma renin activity was further suppressed with SCH 32615 pretreatment (29% compared with 20%, P < 0.001). 4. Small acute increments in plasma brain natriuretic peptide (4 pmol/l) have significant biological effects in normal men without altering plasma atrial natriuretic peptide or cGMP.

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