Role of renal nerves in response to volume expansion in conscious newborn lambs

1989 ◽  
Vol 257 (6) ◽  
pp. R1519-R1525 ◽  
Author(s):  
F. G. Smith ◽  
T. Sato ◽  
O. J. McWeeny ◽  
L. Torres ◽  
J. E. Robillard
Keyword(s):  
Renal Function ◽  
Glomerular Filtration Rate ◽  
Plasma Renin Activity ◽  
Glomerular Filtration ◽  
Atrial Natriuretic Factor ◽  
Volume Expansion ◽  
Filtration Rate ◽  
Plasma Renin ◽  
Renin Activity ◽  
Renal Nerves

The present study was designed to determine the influence of renal nerves in mediating the renal response to volume expansion in conscious newborn lambs. Bilateral renal denervation (n = 9) or sham surgery (n = 14) was carried out in newborn lambs 3 to 4 days before performing experiments. Lambs were between 6 and 12 days of age when studied. Chronic denervation did not alter basal neonatal renal function nor renal hemodynamics. Volume expansion with isotonic saline equal to 5% of body weight was associated with a fall in hematocrit and an increase in mean arterial blood pressure, glomerular filtration rate, urine flow rate, and Na+ excretion in intact and denervated lambs. In intact lambs, atrial natriuretic factor increased from 98 +/- 28 to 176 +/- 48 ng/ml during volume expansion and remained elevated for 1 h after volume expansion. In addition, plasma renin activity fell from 21 +/- 5 to 8 +/- 1 ng.ml-1.h-1 and aldosterone levels fell from 160 +/- 24 to 59 +/- 7 pg/ml by 150 min after the start of volume expansion. Similar changes in atrial natriuretic factor, plasma renin activity, and aldosterone were observed in denervated lambs. However, the increase in glomerular filtration rate, Na+ excretion, and fractional excretion of Na+ after volume expansion were significantly less in denervated than in intact lambs. Thus, in the newborn, the renal nerves do not appear to play a role in influencing basal renal hemodynamics and renal function but, as in the adult, the renal sympathetic nervous system does play a role in regulating fluid and electrolyte excretion during hypervolemia.

Global REACH 2018: Volume regulation in high-altitude Andeans with and without chronic mountain sickness

2021 ◽  
Author(s):  
Andrew R. Steele ◽  
Michael M. Tymko ◽  
Victoria L. Meah ◽  
Lydia L Simpson ◽  
Christopher Gasho ◽  
...  
Keyword(s):  
Glomerular Filtration Rate ◽  
Plasma Renin Activity ◽  
High Altitude ◽  
Glomerular Filtration ◽  
Filtration Rate ◽  
Plasma Renin ◽  
Renin Activity ◽  
Chronic Mountain Sickness ◽  
Plasma Aldosterone Concentration ◽  
Mountain Sickness

The high-altitude maladaptation syndrome known as chronic mountain sickness (CMS) is characterized by polycythemia and is associated with proteinuria despite unaltered glomerular filtration rate. However, it remains unclear if indigenous highlanders with CMS have altered volume regulatory hormones. We assessed N-terminal pro-B-type natriuretic peptide (NT pro-BNP), plasma aldosterone concentration, plasma renin activity, kidney function (urinary microalbumin, glomerular filtration rate), blood volume, and estimated pulmonary artery systolic pressure (ePASP), in Andean males without (n=14; age=39±11) and with (n=10; age=40±12) CMS at 4330 meters (Cerro de Pasco, Peru). Plasma renin activity (non-CMS: 15.8±7.9 vs. CMS: 8.7±5.4 ng/ml; p=0.025) and plasma aldosterone concentration (non-CMS: 77.5±35.5 vs. CMS: 54.2±28.9 pg/ml; p=0.018) were lower in highlanders with CMS compared to non-CMS, while NT pro-BNP was not different between groups (non-CMS: 1394.9±214.3 vs. CMS: 1451.1±327.8 pg/ml; p=0.15). Highlanders had similar total blood volume (non-CMS: 90±15 vs. CMS: 103±18 ml • kg-1; p=0.071), but Andeans with CMS had greater total red blood cell volume (non-CMS: 46±10 vs. CMS 66±14 ml • kg-1; p<0.01) and smaller plasma volume (non-CMS 43±7 vs. CMS 35±5 ml • kg-1; p=0.03) compared to non-CMS. There were no differences in ePASP between groups (non-CMS 32±9 vs. CMS 31±8 mmHg; p=0.6). A negative correlation was found between plasma renin activity and glomerular filtration rate in both groups (group: r=-0.66; p<0.01; non-CMS: r=-0.60; p=0.022; CMS: r=-0.63; p=0.049). A smaller plasma volume in Andeans with CMS may indicate an additional CMS maladaptation to high-altitude, causing potentially greater polycythemia and clinical symptoms.

Factors Related to Potassium Transport in Chronic Stable Renal Disease in Man

1978 ◽  
Vol 54 (6) ◽  
pp. 661-666
Author(s):  
T. Kahn ◽  
D. M. Kaji ◽  
G. Nicolis ◽  
L. R. Krakoff ◽  
R. M. Stein
Keyword(s):  
Glomerular Filtration Rate ◽  
Renal Disease ◽  
Plasma Renin Activity ◽  
Potassium Chloride ◽  
Glomerular Filtration ◽  
Filtration Rate ◽  
Plasma Renin ◽  
Plasma Aldosterone ◽  
Renin Activity ◽  
Control Subjects

1. The inter-relationships between plasma aldosterone, plasma renin activity, potassium excretion and plasma potassium were evaluated in subjects with normal and decreased glomerular filtration rate. 2. In seven studies of healthy control subjects and 12 studies of patients with renal disease, daily urine collections, plasma aldosterone and plasma renin activity were measured on a free diet for 5–10 days and subsequently during the addition of 50 mmol of potassium chloride daily for 5 days. Plasma aldosterone was also measured in 22 hospital patients with normal glomerular filtration rate and 24 patients with reduced glomerular filtration rate. 3. Plasma aldosterone was similar in base-line conditions in patients with or without renal disease and increased similarly during the administration of potassium chloride, suggesting that potassium excretion in patients with reduced glomerular filtration rate probably does not depend primarily upon increased aldosterone. 4. Plasma renin activity increased similarly in control subjects and patients with renal disease during the administration of 50 mmol of potassium chloride/day, but plasma renin activity did not increase when 100 mmol of potassium chloride/day was given to control subjects. 5. With the administration of 50 mmol of potassium chloride/day mean daily potassium excretion increased similarly in control subjects and patients with renal disease but plasma potassium increased significantly (4·7 to 5·4 mmol/l) only in patients with renal disease, suggesting that their uptake of potassium into cells was impaired.

Influence of the renin–angiotensin system in the renal haemodynamic responses to modest renal nerve stimulation in the rat

1982 ◽  
Vol 93 (1) ◽  
pp. 65-70 ◽  
Author(s):  
Stephen Ball ◽  
E. J. Johns
Keyword(s):  
Blood Flow ◽  
Glomerular Filtration Rate ◽  
Plasma Renin Activity ◽  
Glomerular Filtration ◽  
Renal Blood Flow ◽  
Nerve Stimulation ◽  
Filtration Rate ◽  
Plasma Renin ◽  
Renal Nerves ◽  
Filtration Fraction

The renal nerves of the left kidney of sodium-replete anaesthetized rats were stimulated for 30-min periods at 2–3 Hz (15 V, 0·2 ms). Renal blood flow was reduced by 22% and glomerular filtration rate by 14% which resulted in a rise in filtration fraction of 12%. Circulating plasma renin activity was increased by 30% during such nerve stimulation. In rats treated for 3–4 weeks with deoxycorticosterone acetate (DOCA) and saline (150 mm-NaCl) basal values of arterial blood pressure, renal blood flow, glomerular filtration rate and filtration fraction were not significantly different from those observed in sodium-replete rats. However, plasma renin activity was lower, being approximately one-third of that observed in sodium-replete animals. Stimulation of the renal nerves in rats treated with DOCA and saline resulted in a fall in renal blood flow of 32% and a much larger fall in glomerular filtration rate of 33% which resulted in no change in filtration fraction. Plasma renin activity was not changed by renal nerve stimulation in the animals treated with DOCA and saline. It is suggested that these renal responses provide evidence in the rat for a role of locally generated angiotensin II in regulating glomerular filtration rate during electrical activation of the renal nerves by causing preferential vasoconstriction of the efferent arteriole.

The Sodium-Retaining Effect of Renal Nerve Activity in the Cat: Role of Angiotensin Formation

1976 ◽  
Vol 51 (1) ◽  
pp. 93-102 ◽  
Author(s):  
E. J. Johns ◽  
Barbara A. Lewis ◽  
Bertha Singer
Keyword(s):  
Blood Flow ◽  
Glomerular Filtration Rate ◽  
Glomerular Filtration ◽  
Filtration Rate ◽  
Plasma Renin ◽  
Renal Nerves ◽  
Nerve Activity ◽  
Renal Nerve ◽  
Renal Nerve Activity ◽  
Sodium Clearance

1. The effect of low-frequency stimulation of the renal nerves on renal function and renin release has been investigated. The experiments were performed in unilaterally nephrectomized, anaesthetized cats in which the nerves to the remaining kidney were sectioned. 2. When stimulation frequency was adjusted to reduce renal blood flow by approximately 15% for 15 min, glomerular filtration rate was hardly affected. The ratio sodium clearance/glomerular filtration rate was significantly reduced and plasma renin activity was significantly increased. 3. When the renal nerves were similarly stimulated in the presence of the β-adrenergic receptor blocking agent, propranolol, the glomerular filtration rate was significantly reduced and the rise in plasma renin activity was significantly inhibited. The reduction of sodium clearance/glomerular filtration rate was as great as in the control animals. 4. The results are consistent with the view that the maintenance of glomerular filtration rate, during renal nerve stimulation which reduced renal blood flow, may be mediated by the local generation of angiotensin. The results also suggest that angiotensin does not play an important role in the sodium retention associated with increased renal nerve activity.

Effects of synthetic atrial natriuretic factor on renal function and renin release

1984 ◽  
Vol 247 (5) ◽  
pp. F863-F866 ◽  
Author(s):  
J. C. Burnett ◽  
J. P. Granger ◽  
T. J. Opgenorth
Keyword(s):  
Blood Flow ◽  
Renal Function ◽  
Glomerular Filtration Rate ◽  
Glomerular Filtration ◽  
Renal Blood Flow ◽  
Atrial Natriuretic Factor ◽  
Filtration Rate ◽  
Renin Secretion ◽  
Natriuretic Factor ◽  
Atrial Natriuretic

Studies were performed in anesthetized dogs (n = 5) to determine the effects of synthetic atrial natriuretic factor on renal function and renin release. Intrarenal infusion of synthetic atrial natriuretic factor (ANF) (0.3 microgram X kg-1 X min-1) resulted in a transient increase in renal blood flow (126 +/- 8 to 148 +/- 11 ml/min). The duration of this transient vasodilation was 3.1 +/- 0.4 min. Continued infusion was followed by a slight decrease in renal blood flow (126 +/- 8 to 117 +/- 8 ml/min) and an increase in glomerular filtration rate (23.1 +/- 3.5 to 30.7 +/- 1.9 ml/min), with filtration fraction thus being increased (0.19 +/- 0.04 to 0.27 +/- 0.03). These hemodynamic alterations were associated with increases in fractional sodium excretion (0.6 +/- 0.2 to 5.8 +/- 0.8%), fractional potassium excretion (30.8 +/- 9.4 to 56.3 +/- 7.4%), fractional lithium excretion (32.2 +/- 7.1 to 60.3 +/- 5.7%), and fractional phosphate excretion (8.7 +/- 3.5 to 41.6 +/- 11.7%). Intrarenal infusion of synthetic ANF markedly suppressed renin secretion rate (295.5 +/- 84.6 to 17.2 +/- 10.6 ng/min) despite a slight reduction in arterial pressure (123 +/- 9 to 118 +/- 9 mmHg). Our studies demonstrate that synthetic ANF results in a marked natriuretic response that is in part mediated by an increase in glomerular filtration rate. The increase in fractional lithium and phosphate excretion suggests that this factor may also have an action on proximal tubule reabsorption. Further, these studies demonstrate that synthetic ANF markedly inhibits renin secretion.

Clinical Renal Function Testing by External Double Isotope Monitoring Technique

1971 ◽  
Vol 10 (01) ◽  
pp. 16-24
Author(s):  
J. Fog Pedersen ◽  
M. Fog Pedersen ◽  
Paul Madsen
Keyword(s):  
Renal Function ◽  
Glomerular Filtration Rate ◽  
Glomerular Filtration ◽  
Plasma Flow ◽  
Filtration Rate ◽  
Renal Plasma Flow ◽  
Correlation Coefficients ◽  
Feedback System ◽  
Effective Renal Plasma Flow ◽  
Advantages And Disadvantages

SummaryAn accurate catheter-free technique for clinical determination simultaneouslyof glomerular filtration rate and effective renal plasma flow by means of radioisotopes has been developed. The renal function is estimated by the amount of radioisotopes necessary to maintain a constant concentration in the patient’s blood. The infusion pumps are steered by a feedback system, the pumps being automatically turned on when the radiation measured over the patient’s head falls below a certain preset level and turned off when this level is again readied. 131I-iodopyracet was used for the estimation of effective renal plasma flow and125I-iothalamate estimation of the glomerular filtration rate. These clearances were compared to the conventional bladder clearances and good correlation was found between these two clearance methods (correlation coefficients 0.97 and.90 respectively). The advantages and disadvantages of this new clearance technique are discussed.

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