Contribution of peripheral pooling to the renal response to immersion in the dog

1978 ◽  
Vol 45 (5) ◽  
pp. 786-790 ◽  
Author(s):  
I. H. Zucker ◽  
J. P. Gilmore
Keyword(s):  
Renal Plasma Flow ◽  
Water Immersion ◽  
Venous Pressure ◽  
Free Water ◽  
Urine Flow ◽  
Peripheral Vascular ◽  
Central Venous ◽  
Free Water Clearance ◽  
Hormone Administration ◽  
Cervical Vagotomy

The present investigation evaluated the renal and hemodynamic responses to head-out water immersion in dogs. Dogs were immersed in the vertical (seated) position in a 34 degrees C bath. Urine flow (V), osmolar clearance (Cosm), free water clearance (CH2O), sodium excretion (UNa+V), potassium excretion (UK+V), GFR, effective renal plasma flow (ERPF), central venous pressure (CVP), and cardiac output (CO) all increased significantly during immersion. This response was unchanged by bilateral cervical vagotomy or by deoxycorticosterone acetate and antidiuretic hormone administration. The control values of these dogs were low and indicated a state of peripheral vascular pooling which was readjusted to normal by the immersion maneuver. The renal and hemodynamic values during the period of immersion were similar to values of a group of dogs which were recumbent in air. Furthermore, when the latter group of dogs were tilted head down 19 degrees, there was no further increase in any of the measured parameters. These data are consistent with the view that water immersion in the upright dog simply redistributes blood volume back to that level seen in the recumbent dog, a position which is more natural for this species.

Volume-homeostatic mechanisms in humans during graded water immersion

1994 ◽  
Vol 77 (6) ◽  
pp. 2832-2839 ◽  
Author(s):  
A. S. Larsen ◽  
L. B. Johansen ◽  
C. Stadeager ◽  
J. Warberg ◽  
N. J. Christensen ◽  
...  
Keyword(s):  
Water Immersion ◽  
Venous Pressure ◽  
Plasma Concentrations ◽  
Free Water ◽  
Urine Flow ◽  
Central Venous ◽  
Free Water Clearance ◽  
Graded Release ◽  
Homeostatic Mechanisms ◽  
Healthy Males

The purpose of this experiment was to investigate whether a graded increase in cardiac distension induced by graded water immersion (WI) could be related to endocrine responses and renal sodium excretion (UNaV). On 3 separate days, nine healthy males were investigated in the upright seated position before, during, and after 3 h of WI to the midchest (CI) or to the neck (NI) or during control. Central venous pressure increased twice as much during NI as during CI. UNaV increased to the same extent during NI compared with CI, whereas urine flow rate, solute-free water clearance, and osmotic excretion increased more during the 2nd h of NI than during CI. During NI, the plasma concentration of atrial natriuretic peptide (ANP) increased twice as much as during CI. The plasma concentrations of aldosterone and norepinephrine were decreased in a similar manner during NI compared with CI. In conclusion, graded cardiac distension induced by graded WI and accompanied by a graded release of ANP was not accompanied by a graded increase in UNaV. Thus either a cardiac distension pressure of approximately one-half of that during NI is enough to induce a maximum UNaV during WI or other stimuli are important. Furthermore, aldosterone and norepinephrine are probably more important mediators of the natriuresis of WI in humans than is ANP.

The Role of Cardiopulmonary Sympathetic Afferents in Blood Volume Homoeostasis in the Non-Human Primate

1983 ◽  
Vol 64 (3) ◽  
pp. 281-287 ◽  
Author(s):  
Kurtis G. Cornish ◽  
Joseph P. Gilmore
Keyword(s):  
Blood Pressure ◽  
Central Venous Pressure ◽  
Blood Volume ◽  
Volume Expansion ◽  
Venous Pressure ◽  
Free Water ◽  
Urine Flow ◽  
Central Venous ◽  
Free Water Clearance ◽  
Human Primate

1. Four Macaca fascicularis monkeys were bilaterally sympathectomized by removing the thoracic sympathetic chain from the middle cervical ganglion to the T-6 sympathetic ganglion. This was done chronically, allowing adequate recovery time. While under light pentobarbital anaesthesia, the animals were then subjected to blood volume expansions with isotonic, isooncotic dextran or to head-out immersions. Seven immersions and seven volume expansions were carried out. 2. With immersion, there were significant increases in blood pressure, central venous pressure, urine flow, sodium excretion, potassium excretion, glomerular filtration rate, percentage of filtered sodium excreted and free water clearance. Although blood pressure and central venous pressure initially increased during the first immersion period, heart rate continued to increase with the immersion, while blood pressure and central venous pressure remained constant. Volume expansion caused an increase in central venous pressure, urine flow, sodium and potassium excretion, osmolar clearance, free water clearance, percentage of filtered sodium excreted and glomerular filtration rate. 3. Since these results with both the immersions and volume expansions were not qualitatively different from those observed in control animals, it is concluded that cardiopulmonary sympathetic afferents are not necessary for the renal response to head-out immersion or blood volume expansion in the non-human primate.

Role of ANP in natriuresis of head-out immersion in humans

1989 ◽  
Vol 257 (3) ◽  
pp. F375-F382 ◽  
Author(s):  
T. J. Rabelink ◽  
H. A. Koomans ◽  
P. Boer ◽  
C. A. Gaillard ◽  
E. J. Dorhout Mees
Keyword(s):  
Renal Plasma Flow ◽  
Water Immersion ◽  
Free Water ◽  
Urine Osmolality ◽  
Sodium Absorption ◽  
Free Water Clearance ◽  
Target Segment ◽  
Small Rise ◽  
Natriuretic Effect

Atrial natriuretic peptide (ANP) may play a role in the natriuresis after acute circulatory challenges. To assess this role in head-out water immersion (HOI), we compared in clearance studies the effect of 3 h HOI with an equally natriuretic 3-h infusion of ANP [0.01 microgram.kg-1.min-1 human ANP-(99-126)] in seven healthy individuals taking a 100 mmol sodium diet. The studies were repeated after treatment with enalapril (20 mg twice daily), which in previous studies inhibited the natriuresis after ANP. HOI caused a natriuresis equal to that of ANP infusion despite an about five times smaller rise in plasma ANP. HOI increased and ANP decreased estimated renal plasma flow (ERPF). HOI increased maximal free water clearance and decreased fractional lithium reabsorption. ANP did not affect these variables but raised minimal urine osmolality. Enalapril enhanced the fall in ERPF caused by ANP and abolished its natriuretic effect; enalapril did not impair either the natriuresis after HOI or the increase in ERPF and the fall in lithium reabsorption. These data indicate that the low dosage of ANP causes natriuresis by reducing sodium absorption in a distal nephron target segment; enalapril impairs this effect, perhaps by enhancing ANP-induced vasoconstriction, which decreases delivery to this target segment. HOI, by increasing sodium delivery to this segment, is natriuretic despite only a small rise in plasma ANP. Enalapril does not impair these effects. Although a rise in plasma ANP may be one factor in the natriuresis of HOI, the present data speak against an exclusive role. Other factors determine the magnitude of the natriuretic response.

Cardiovascular, renal, and endocrine responses in male quadriplegics during head-out water immersion

1990 ◽  
Vol 258 (6) ◽  
pp. R1424-R1430 ◽  
Author(s):  
F. Tajima ◽  
S. Sagawa ◽  
J. Iwamoto ◽  
K. Miki ◽  
B. J. Freund ◽  
...  
Keyword(s):  
Water Immersion ◽  
Urine Volume ◽  
Systolic Pressure ◽  
Free Water ◽  
Plasma Renin ◽  
Normal Subjects ◽  
Urine Flow ◽  
Cervical Cord ◽  
Free Water Clearance ◽  
Normal Men

The present study was undertaken to determine the relative influence of the action of the central nervous system on the mechanism of water-immersion-induced diuresis by comparing physiological responses of quadriplegic (QP) and normal subjects. After overnight fasting seven male QP subjects with complete cervical cord transections (C5-C8) and six normal men were tested before, during, and after 3 h of head-out immersion (HOI) in thermoneutral water (34.5-35.0 degrees C). The reversible increase in urine flow and the total urine volume (309 +/- 53 ml in 3 h) in QP subjects were comparable with that of the normal subjects (318 +/- 96 ml in 3 h). While osmolal excretion was increased in QP subjects, its magnitude was less when compared with that of normal subjects. Instead, the increased urine flow in QP subjects was characterized by increased glomerular filtration rate (GFR) and free water clearance, in contrast to a predominantly osmotic diuresis with no changes in GFR in the normal subjects. The HOI elevated (P less than 0.05) systolic pressure only in QP subjects, whereas the increase in cardiac output was the same in both groups. While plasma renin activity and aldosterone responses to HOI in QP subjects were comparable with those of normal individuals, plasma atrial natriuretic factor (ANF) in QP subjects was twofold higher (P less than 0.05) during HOI, and the approximately threefold increase in ANF (P less than 0.05) in QP subjects due to HOI was the same as that of normal subjects.(ABSTRACT TRUNCATED AT 250 WORDS)

Antigravity suit inflation: kidney function and cardiovascular and hormonal responses in men

1989 ◽  
Vol 66 (2) ◽  
pp. 792-799 ◽  
Author(s):  
G. Geelen ◽  
S. E. Kravik ◽  
A. Hadj-Aissa ◽  
G. Leftheriotis ◽  
M. Vincent ◽  
...  
Keyword(s):  
Kidney Function ◽  
Renal Plasma Flow ◽  
Water Immersion ◽  
Free Water ◽  
Plasma Renin ◽  
Bed Rest ◽  
Urine Flow ◽  
Positive Pressure ◽  
Plasma Sodium ◽  
Lower Body Positive Pressure

To investigate the effects of lower body positive pressure (LBPP) on kidney function while controlling certain cardiovascular and endocrine responses, seven men [35 +/- 2 (SE) yr] underwent 30 min of sitting and then 4.5 h of 70 degrees head-up tilt. An antigravity suit was applied (60 Torr legs, 30 Torr abdomen) during the last 3 h of tilt. A similar noninflation experiment was conducted where the suited subjects were tilted for 3.5 h. To provide adequate urine flow, the subjects were hydrated during the course of both experiments. Immediately after inflation, mean arterial pressure increased by 8 +/- 3 Torr and pulse rate decreased by 16 +/- 3 beats/min. Plasma renin activity and aldosterone were maximally suppressed (P less than 0.05) after 2.5 h of inflation. Plasma vasopressin decreased by 40–50% (P less than 0.05) and plasma sodium and potassium remained unchanged during both experiments. Glomerular filtration rate was not increased significantly by inflation, whereas inflation induced marked increases (P less than 0.05) in effective renal plasma flow (ERPF), urine flow, osmolar and free water clearances, and total and fractional sodium excretion. No such changes occurred during control. Thus, LBPP induces 1) a significant increase in ERPF and 2) significant changes in kidney excretory patterns similar to those observed during water immersion or the early phase of bed rest, situations that also result in central vascular volume expansion.

Renal activity of vasopressin in anesthetized dogs

1961 ◽  
Vol 200 (2) ◽  
pp. 400-404 ◽  
Author(s):  
Joseph H. Perlmutt
Keyword(s):  
Filtration Rate ◽  
Renal Plasma Flow ◽  
Free Water ◽  
Urine Osmolality ◽  
Urine Flow ◽  
Urinary Concentration ◽  
Urinary Ph ◽  
Free Water Clearance ◽  
Anesthetized Dogs ◽  
Sustained Increase

Conventional clearance techniques were used to study the renal response to vasopressin (5–100 mu/hr.) infused for 2 1/2 hours into anesthetized (pentobarbital), surgically traumatized dogs elaborating a dilute urine. Decreased urine flow, a concomitant sustained increase in Na+ excretion, increased urine osmolality, negative free-water clearance and an increased osmolal U/P ratio (>1, <2) consistently occurred during the infusion of 50 mu/hr. Urinary pH rose and HCO3–, rather than Cl–, was the predominant anion excreted. Tubular rejection of HCO3–, however, is not essential for vasopressin activity under the conditions of this investigation since antidiuresis occurred in an acidotic dog. Usually some increase in glomerular filtration rate and effective renal plasma flow were apparent during vasopressin infusion; the former change could account for the increased Na+ excretion, but it is difficult to ascribe the peculiar anion behavior to this factor. Maximum urinary concentration was not attained even with 100 mu vasopressin/hr.

Renal hemodynamics, tubular function, and response to low-dose dopamine during acute hypoxia in humans

1993 ◽  
Vol 74 (5) ◽  
pp. 2166-2173 ◽  
Author(s):  
N. V. Olsen ◽  
J. M. Hansen ◽  
I. L. Kanstrup ◽  
J. P. Richalet ◽  
P. P. Leyssac
Keyword(s):  
Renal Plasma Flow ◽  
Acute Hypoxia ◽  
Nervous Activity ◽  
Free Water ◽  
Normal Subjects ◽  
Urine Flow ◽  
Tubular Function ◽  
Plasma Norepinephrine ◽  
Free Water Clearance ◽  
Proximal Tubular

Renal function was investigated in eight normal subjects before and during infusion of dopamine (3 micrograms.kg-1 x min-1) at sea level (SL) and at high altitude (HA, 4,350 m). Lithium clearance (CLi) was used as an index of proximal tubular outflow. HA significantly increased arterial pressure, heart rate, and plasma norepinephrine. Effective renal plasma flow (ERPF) decreased at HA by 10% (P < 0.05), but glomerular filtration rate (GFR), CLi, sodium clearance (CNa), and urine flow remained unchanged compared with SL. Dopamine at SL and HA increased ERPF by 47% (P < 0.001) and 30% (P < 0.01), respectively, but the increase at HA was smaller than that at SL (P < 0.05). Dopamine increased GFR only at SL. CLi and CNa increased by 29% (P < 0.001) and 108% (P < 0.001) at SL and by 23% (P < 0.01) and 108% (P < 0.001) at HA. Whereas dopamine at SL increased urine flow by 46% (P < 0.01), this response was abolished at HA, and free water clearance decreased (P < 0.05). The decreased ERPF at HA suggests a constriction of the renal arterioles secondary to increased adrenergic nervous activity. Although the effect of dopamine on ERPF was attenuated in hypoxia, dopamine-induced increases in CLi and CNa remained unaltered, suggesting that natriuresis in both environments was secondary to an increased outflow from the proximal tubules. The absence of a diuretic response to dopamine at HA seemed to be caused by an effect on distal tubular function.

Renal and humoral responses to sustained cardiopulmonary baroreceptor deactivation in humans

1991 ◽  
Vol 260 (3) ◽  
pp. R642-R648 ◽  
Author(s):  
J. A. Miller ◽  
J. S. Floras ◽  
K. L. Skorecki ◽  
L. M. Blendis ◽  
A. G. Logan
Keyword(s):  
Lower Body Negative Pressure ◽  
Renal Plasma Flow ◽  
Venous Pressure ◽  
Plasma Concentrations ◽  
Free Water ◽  
Plasma Norepinephrine ◽  
Free Water Clearance ◽  
Arterial Blood ◽  
Cardiopulmonary Baroreflex ◽  
Water Clearance

The renal and neurohumoral effects of prolonged cardiopulmonary baroreflex unloading and the relationship of these changes to urinary sodium excretion have not been well documented in humans. In this study, 12 normal males underwent lower body negative pressure at -15 mmHg for 90 min, a maneuver that deactivates cardiopulmonary baroreceptors. Glomerular filtration rate (GFR), effective renal plasma flow (ERPF), and filtration fraction (FF) were measured in eight of these subjects using inulin and p-aminohippuric acid clearance techniques. During reduction of central venous pressure, arterial blood pressure and heart rate did not change. Plasma concentrations of atrial natriuretic factor (ANF) decreased markedly (22 +/- 2 to 12 +/- 1 pg/ml, P = 0.0001) as did the second messenger of ANF's biological action, guanosine 3',5'-cyclic monophosphate, whereas renin and vasopressin were not significantly altered. There was a significant rise in plasma norepinephrine (1.6 +/- 0.2 to 2.4 +/- 0.4 nmol/l, P = 0.03). GFR (104 +/- 9 to 68 +/- 6 ml/min, P = 0.007) and FF (0.18 +/- 0.01 to 0.14 +/- 0.01, P = 0.007) decreased significantly, with maintenance of ERPF. There was a significant antinatriuresis without an antikaliuresis and a significant reduction in free water clearance. These changes in renal hemodynamics are unlike the known effects of renal vasoconstrictors, and the alterations in solute and free water clearance are consistent with the removal of the known actions of ANF from tubular target sites. Taken together, our findings suggest that a mechanism other than activation of vasoconstrictors, possibly the diminution of the influence of ANF on the kidney, may be operative in the renal adjustments to cardiopulmonary baroreflex deactivation in humans.

Arginine vasopressin, circulation, and kidney during graded water immersion in humans

1986 ◽  
Vol 61 (2) ◽  
pp. 565-574 ◽  
Author(s):  
P. Norsk ◽  
F. Bonde-Petersen ◽  
J. Warberg
Keyword(s):  
Arginine Vasopressin ◽  
Water Immersion ◽  
Venous Pressure ◽  
Free Water ◽  
Systolic Arterial Pressure ◽  
Free Water Clearance ◽  
Plasma Arginine ◽  
Normal Males ◽  
Solute Excretion ◽  
Rebreathing Method

Ten normal males rested sitting upright at an air temperature of 28 degrees C for 5.5 h (control, C) and underwent 4 h of graded water immersion (WI) to the umbilicus (UI), to the chest (CI), and to the neck (NI), respectively (water temperature = 34.5 degrees C), on different experimental days. Plasma arginine vasopressin (PAVP) was suppressed during WI compared with C and maximally so during NI. However, there was no change in PAVP comparing CI with UI even though central venous pressure (CVP) increased. CVP increased during CI and NI compared with C but was unchanged during UI, whereas cardiac output (rebreathing method), stroke volume, and plasma volume increased to approximately the same level during all three steps of WI compared with C. Heart rate and total peripheral vascular resistance decreased during UI, CI, and NI. Systolic arterial pressure (SAP) and pulse pressure (PP) were increased gradually from prestudy related to the degree of WI. Also diuresis, natriuresis, kaliuresis, osmotic excretion, and clearance were increased gradually compared with C, whereas free water clearance (CH2O) gradually decreased. There were weak negative but statistically significant correlations between PAVP and CVP and between changes in PAVP from prestudy and corresponding changes in SAP and PP. Furthermore, a statistically significant and negative correlation between CH2O and natriuresis could be established. We conclude that graded immersion gradually increases central blood volume and decreases PAVP. However, not only cardiopulmonary mechanoreceptors but also arterial baroreceptors may play a role in AVP suppression during WI in humans. In hydropenic subjects the suppression of PAVP during WI is apparently not effective in counteracting the decrease in CH2O induced by increased solute excretion.

Contribution of abdomen and legs to central blood volume expansion in humans during immersion

1997 ◽  
Vol 83 (3) ◽  
pp. 695-699 ◽  
Author(s):  
Lars Bo Johansen ◽  
Thomas Ulrik Skram Jensen ◽  
Bettina Pump ◽  
Peter Norsk
Keyword(s):  
Blood Volume ◽  
Volume Expansion ◽  
Protein Concentration ◽  
Water Immersion ◽  
Venous Pressure ◽  
Cuff Inflation ◽  
Central Blood Volume ◽  
Central Venous ◽  
Plasma Protein Concentration ◽  
Blood Volume Expansion

Johansen, Lars Bo, Thomas Ulrik Skram Jensen, Bettina Pump, and Peter Norsk. Contribution of abdomen and legs to central blood volume expansion in humans during immersion. J. Appl. Physiol. 83(3): 695–699, 1997.—The hypothesis was tested that the abdominal area constitutes an important reservoir for central blood volume expansion (CBVE) during water immersion in humans. Six men underwent 1) water immersion for 30 min (WI), 2) water immersion for 30 min with thigh cuff inflation (250 mmHg) during initial 15 min to exclude legs from contributing to CBVE (WI+Occl), and 3) a seated nonimmersed control with 15 min of thigh cuff inflation (Occl). Plasma protein concentration and hematocrit decreased from 68 ± 1 to 64 ± 1 g/l and from 46.7 ± 0.3 to 45.5 ± 0.4% ( P < 0.05), respectively, during WI but were unchanged during WI+Occl. Left atrial diameter increased from 27 ± 2 to 36 ± 1 mm ( P < 0.05) during WI and increased similarly during WI+Occl from 27 ± 2 to 35 ± 1 mm ( P < 0.05). Central venous pressure increased from −3.7 ± 1.0 to 10.4 ± 0.8 mmHg during WI ( P < 0.05) but only increased to 7.0 ± 0.8 mmHg during WI+Occl ( P < 0.05). In conclusion, the dilution of blood induced by WI to the neck is caused by fluid from the legs, whereas the CBVE is caused mainly by blood from the abdomen.

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