Early Changes in Renal Function during Isotonic Saline Infusion in the Rat

2015 ◽  
pp. 67-71
Author(s):  
J. Heller
Keyword(s):  
Renal Function ◽  
Isotonic Saline ◽  
Saline Infusion

Acute and chronic increases in osmolality increase excitatory amino acid drive of the rostral ventrolateral medulla in rats

2004 ◽  
Vol 287 (6) ◽  
pp. R1359-R1368 ◽  
Author(s):  
Virginia L. Brooks ◽  
Korrina L. Freeman ◽  
Theresa L. O’Donaughy
Keyword(s):  
Amino Acid ◽  
Arterial Pressure ◽  
Blood Volume ◽  
Excitatory Amino Acid ◽  
Isotonic Saline ◽  
Plasma Osmolality ◽  
Saline Infusion ◽  
Ventrolateral Medulla ◽  
Depressor Response ◽  
Hypertonic Saline Infusion

Water deprivation is associated with increased excitatory amino acid (EAA) drive of the rostral ventrolateral medulla (RVLM), but the mechanism is unknown. This study tested the hypotheses that the increased EAA activity is mediated by decreased blood volume and/or increased osmolality. This was first tested in urethane-anesthetized rats by determining whether bilateral microinjection of kynurenate (KYN, 2.7 nmol) into the RVLM decreases arterial pressure less in water-deprived rats after normalization of blood volume by intravenous infusion of isotonic saline or after normalization of plasma osmolality by intravenous infusion of 5% dextrose in water (5DW). Water-deprived rats exhibited decreased plasma volume and elevated plasma osmolality, hematocrit, and plasma sodium, chloride, and protein levels (all P < 0.05). KYN microinjection decreased arterial pressure by 24 ± 2 mmHg ( P < 0.05; n = 17). The depressor response was not altered following isotonic saline infusion but, while still present ( P < 0.05), was reduced ( P < 0.05) to −13 ± 2 mmHg soon after 5DW infusion. These data suggest that the high osmolality, but not low blood volume, contributes to the KYN depressor response. To further investigate the action of increased osmolality on EAA input to RVLM, water-replete rats were also studied after hypertonic saline infusion. Whereas KYN microinjection did not decrease pressure immediately following the infusion, a depressor response gradually developed over the next 3 h. Lumbar sympathetic nerve activity also gradually increased to up to 167 ± 19% of control ( P < 0.05) 3 h after hypertonic saline infusion. In conclusion, acute and chronic increases in osmolality appear to increase EAA drive of the RVLM.

Isotonic Saline Infusion Stimulates Plasma Release of Atrial Natriuretic Peptide (ANP) in Man

1986 ◽  
Vol 70 (s13) ◽  
pp. 74P-74P ◽  
Author(s):  
JV Anderson ◽  
J Donckier ◽  
W McKenna ◽  
ACR Burns ◽  
SR Bloom
Keyword(s):  
Atrial Natriuretic Peptide ◽  
Natriuretic Peptide ◽  
Isotonic Saline ◽  
Saline Infusion ◽  
Atrial Natriuretic

Roles of cephalic Na+ concentration and urodilatin in control of renal Na+ excretion

1992 ◽  
Vol 262 (3) ◽  
pp. F513-F516 ◽  
Author(s):  
C. Emmeluth ◽  
C. Drummer ◽  
R. Gerzer ◽  
P. Bie
Keyword(s):  
Renal Function ◽  
Volume Expansion ◽  
Carotid Arteries ◽  
Jugular Vein ◽  
Isotonic Saline ◽  
Fold Increase ◽  
Sodium Concentration ◽  
Fourfold Increase ◽  
Infusion Technique ◽  
Water Contents

Effects on renal function of an increase in the concentration of sodium in the blood supplying the head were investigated in water-diuretic conscious dogs in which the sodium and water contents were controlled by separate servo-mechanisms. A selective 2% increase in the sodium concentration of the carotid blood was achieved by a split-infusion technique including infusions of hypertonic saline into both carotid arteries and water into a jugular vein at rates making the combined infusate isotonic. This procedure caused a 34-fold increase in renal sodium excretion concomitant with a fourfold increase in the rate of urinary excretion of urodilatin. A comparable isotonic volume expansion (isotonic saline infusion into carotid arteries and jugular vein) caused a significantly smaller (13-fold) increase in urinary rate of excretion of sodium (P less than 0.02) and no increase at all in the excretion of urodilatin. It is hypothesized that cephalic sodium concentration receptors regulate the rate of excretion of sodium via urodilatin even under the present slightly hypotonic conditions.

Effect of lymphatic outflow pressure on lymphatic albumin transport in humans

2001 ◽  
Vol 91 (3) ◽  
pp. 1223-1228 ◽  
Author(s):  
Jauchia Wu ◽  
Gary W. Mack
Keyword(s):  
Protein Transport ◽  
Lower Body Negative Pressure ◽  
Venous Pressure ◽  
Isotonic Saline ◽  
Saline Infusion ◽  
Positive Pressure ◽  
Lower Body ◽  
Lower Body Positive Pressure ◽  
The Difference ◽  
The Impact

The effects of posture on the lymphatic outflow pressure and lymphatic return of albumin were examined in 10 volunteers. Lymph flow was stimulated with a bolus infusion of isotonic saline (0.9%, 12.6 ml/kg body wt) under four separate conditions: upright rest (Up), upright rest with lower body positive pressure (LBPP), supine rest (Sup), and supine rest with lower body negative pressure (LBNP). The increase in plasma albumin content (ΔAlb) during the 2 h after bolus saline infusion was greater in Up than in LBPP: 82.9 ± 18.5 vs. −28.4 mg/kg body wt. ΔAlb was greater in LBNP than in Sup: 92.6 vs. −22.5 ± 18.9 mg/kg body wt ( P < 0.05). The greater ΔAlb in Up and Sup with LBNP were associated with a lower estimated lymphatic outflow pressure on the basis of the difference in central venous pressure (ΔCVP). During LBPP, CVP was increased compared with Up: 3.8 ± 1.4 vs. −1.2 ± 1.2 mmHg. During LBNP, CVP was reduced compared with Sup: −3.0 ± 2.2 vs. 1.7 ± 1.0 mmHg. The translocation of protein into the vascular space after bolus saline infusion reflects lymph return of protein and is higher in Up than in Sup. Modulation of CVP with LBPP or LBNP in Up and Sup, respectively, reversed the impact of posture on lymphatic outflow pressure. Thus posture-dependent changes in lymphatic protein transport are modulated by changes in CVP through its mechanical impact on lymphatic outflow pressure.

Effect of saline infusion during exercise on thermal and circulatory regulations

1990 ◽  
Vol 69 (2) ◽  
pp. 609-616 ◽  
Author(s):  
H. Nose ◽  
G. W. Mack ◽  
X. R. Shi ◽  
K. Morimoto ◽  
E. R. Nadel
Keyword(s):  
Forearm Blood Flow ◽  
Isotonic Saline ◽  
Cycle Ergometer ◽  
Saline Infusion ◽  
Minor Effect ◽  
Ambient Temperatures ◽  
Cool Environment ◽  
Constant Rate ◽  
Acute Increase ◽  
A Minor

To quantify the effect of an acute increase in plasma volume (PV) on forearm blood flow (FBF), heart rate (HR), and esophageal temperature (Tes) during exercise, we studied six male volunteers who exercised on a cycle ergometer at 60% of maximal aerobic power for 50 min in a warm [(W), 30 degrees C, less than 30% relative humidity (rh)] or cool environment [(C), 22 degrees C, less than 30% rh] with isotonic saline infusion [Inf(+)] or without infusion [Inf(-)]. The infusion was performed at a constant rate of 0.29 ml.kg body wt-1.min-1 for 20-50 min of exercise to mimic fluid intake during exercise. PV decreased by approximately 5 ml/kg body wt within the first 10 min of exercise in all protocols. Therefore, PV in Inf(-) was maintained at the same reduced level by 50 min of exercise in both ambient temperatures, whereas PV in Inf(+) increased toward the preexercise level and recovered approximately 4.5 ml/kg body wt by 50 min in both temperatures. The restoration of PV during exercise suppressed the HR increase by 6 beats/min at 50 min of exercise in W; however, infusion had no effect on HR in C. In W, FBF in Inf(+) continued to increase linearly as Tes rose to 38.1 degrees C by the end of exercise, whereas FBF in Inf(-) plateaued when Tes reached approximately 37.7 degrees C. The infusion in C had only a minor effect on FBF.(ABSTRACT TRUNCATED AT 250 WORDS)

Renal and hormonal responses to isotonic saline infusion after 3 days' head-down tilt vs. supine and seated positions

2003 ◽  
Vol 177 (2) ◽  
pp. 167-176 ◽  
Author(s):  
P. Mauran ◽  
S. Sediame ◽  
A. Pavy-Le Traon ◽  
A. Maillet ◽  
A. Carayon ◽  
...  
Keyword(s):  
Isotonic Saline ◽  
Saline Infusion ◽  
Hormonal Responses

Atrial natriuretic peptide levels during acute and chronic saline loading in conscious dogs

1986 ◽  
Vol 251 (3) ◽  
pp. R499-R503 ◽  
Author(s):  
F. J. Salazar ◽  
J. C. Romero ◽  
J. C. Burnett ◽  
S. Schryver ◽  
J. P. Granger
Keyword(s):  
Atrial Natriuretic Peptide ◽  
Urinary Excretion ◽  
Natriuretic Peptide ◽  
Sodium Intake ◽  
Plasma Concentrations ◽  
Isotonic Saline ◽  
Saline Infusion ◽  
Plasma Aldosterone Concentration ◽  
Saline Loading ◽  
Atrial Natriuretic

The purpose of the present study was to determine if acute and chronic increases in sodium intake by isotonic saline infusion are accompanied by changes in plasma concentrations of atrial natriuretic peptide (PANP). Acute saline loading (5% body wt) over a 30-min period in seven conscious chronically instrumented dogs produced a significant increase in PANP (48 +/- 5 to 119 +/- 24 pg/ml, P less than 0.05). However, chronic and progressive increments of sodium intake from 5 to 75 to 300 meq/day for 7 days, each by isotonic saline infusion, were examined in the same group of dogs and had no significant effect on PANP. PANP's were 37 +/- 7, 39 +/- 8, and 33 +/- 5 pg/ml when sodium intake was changed from 5 to 75 to 300 meq/day, respectively. The increase of sodium intake from 5 to 75 meq/day produced decreases of plasma renin activity (PRA) (2.5 +/- 0.5 to 1.5 +/- 0.4 ng angiotensin I X ml-1 X h-1, P less than 0.05), plasma aldosterone concentration (PAC) (19.3 +/- 5.4 to 2.9 +/- 0.4 pg/ml, P less than 0.05), and urinary excretion of prostaglandin E2 (760 +/- 131 to 320 +/- 58 pg/min, P less than 0.05). Further increase of sodium intake to 300 meq/day induced decreases of PRA and PAC to undetectable levels and an increase of urinary excretion of 6-ketoprostaglandin F1 alpha (649 +/- 95 to 1,056 +/- 148 pg/min, P less than 0.05). Before the completion of the study, sodium intake was decreased from 300 to 75 meq/day.(ABSTRACT TRUNCATED AT 250 WORDS)

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