Resetting of 24-h sodium and water balance during 4 days of servo-controlled reduction of renal perfusion pressure

Reinhardt, H. W.; Corea, M.; Boemke, Willehad; Pettker, R.; Rothermund, Lars; Scholz, Arne; Schwietzer, G.; Persson, Pontus B.

doi:10.1152/ajpheart.1994.266.2.h650

Cited by 21 publications

(49 citation statements)

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“…For example, acute experiments in conscious dogs have shown that, when an increase in renal perfusion pressure during saline infusion is pre vented by a servo-control mechanism, the usual increases in UV and Uv,V were diminished [22]. However, when renal perfusion pressure was reduced for 4 days, the initially positive Na and water balances were reset to control levels after only I or 2 days [23], but the shift in US:,V and UV towards the night, which was also found in these protocols, persisted.…”

Section: Discussionmentioning

confidence: 99%

Influence of Captopril on 24-Hour Balances and the Diurnal Patterns of Urinary Output, Blood Pressure, Aldosterone and Atrial Natriuretic Peptide in Conscious Dogs

Boemke¹,

Palm²,

Mohnhaupt³

et al. 1995

Kidney Blood Press Res

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The diurnal time course of urinary flow rate (UV), urinary sodium (U_NaV), and potassium (U_KV) excretion, and of hormones such as atrial natriuretic peptide (ANP) and aldosterone, was investigated during 5 days of continuous captopril infusion (15 µg · kg body weigth^-1 · min^-1) in 4 conscious dogs on a high sodium diet (14.5 mmol Na·kg body weigth^-1 24 h^-1). All food and water was given once daily at 8.30 a.m. On the control day and on days 1, 3, and 5 of·captopril infusion, urine was collected by an automated system at 20-min intervals over 24 h, blood was taken every 4 h. Mean arterial blood pressure (MABP) and heart rate were evaluated as 5-min averages. Time courses of U_NaV, UV, and UKV were compared with the individual control day without captopril. With captopril, 24-hour balances for Na and H₂0 were slightly negative, while the K balance was slightly positive for 2-3 days. Thereafter, all 24-hour balances were restored. MABP continued to decrease even after Na and water intake and output had come into balance again. Captopril treatment changed the diurnal excretion pattern for U_NaV and UV characteristically. In the postprandial period until 5 p.m., less Na and urine were excreted than on the control day, whereas during the evening and night more Na and urine were excreted. The changes in the excretion pattern persisted for the entire observation period. The results indicate that disturbances in the regulating systems, induced by converting-enzyme blockade, bring about complex reactions of, e.g., MABP ANP and aldosterone that finally restore Na and water 24-hour input/output balances.

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Section: Discussionmentioning

confidence: 99%

Influence of Captopril on 24-Hour Balances and the Diurnal Patterns of Urinary Output, Blood Pressure, Aldosterone and Atrial Natriuretic Peptide in Conscious Dogs

Boemke¹,

Palm²,

Mohnhaupt³

et al. 1995

Kidney Blood Press Res

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“…After 1 or 2 days of sodium retention the 24-hour sodium input/output returned to bal ance. This phenomenon was termed 'pressure escape' [3]. The present study investigated whether 'pressure escape' is also combined with a change in the excretion pattern for sodium.…”

Section: Introductionmentioning

confidence: 95%

“…The tip of the first catheter was placed above, the tip of the second catheter below the renal arteries [5,6]. When not in use, the catheters were filled with a mixture of gentamicin and u-chymotrypsin to prevent clotting and catheter-relat ed infections [7], One week later, an inflatable silastic occluder was placed around the aorta just proximal to the renal arteries, and a urinary bladder catheter was implanted [3]. The tube of the occluder cuff as well as all catheters were exteriorized between the scapulae.…”

Section: Dog Preparation and Instrumentationmentioning

confidence: 99%

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Diurnal Pattern of Sodium Excretion in Dogs with and without Chronically Reduced Renal Perfusion Pressure

Corea

Seeliger²,

Boemke³

et al. 1996

Kidney Blood Press Res

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In 5 conscious dogs the diurnal patterns of urinary sodium excretion (U_NaV) were investigated, initially during 1 control day and, thereafter, during 4 days of servo-controlled reduction of renal perfusion pressure (rRPP). The individual dog’s mean arterial blood pressure was reduced to 80% of the blood pressure on the control day. This value was always found to be below the threshold for the pressure-dependent renin release. During the entire study period urine was collected in 4-hour intervals and blood samples were taken every 4 h. The dogs were kept on a standardized high sodium and high water intake and were fed once daily at 8.30 h. On the control day, U_NaV, urinary flow rate (UV), fractional lithium excretion (FE_Li) and fractional sodium excretion (FE_Na) had similar diurnal patterns. They peaked 4-8 h after food intake and decreased to low values during the night. On day 1 of rRPP, U_NaV and FE_Na were maintained at very low levels in all collection periods, whereas the patterns of UV and FE_Li were unaltered compared with the patterns on the control day. On days 2-4of rRPP, a clear-cut maximum in the patterns of U_NaV and FE_Na recurred, comparable with the patterns on the control day. However, compared with the control day this maximum was shifted by 4 h towards the night. In contrast, the patterns of UV and FE_Li remained unchanged compared with the control day. The results indicate that U_NaV has a typical time course in conscious, sodium- and water-replete dogs fed once daily. Endogenous stimulation of sodium reabsorption by means of rRPP results in a characteristic 4-hour shift of U_NaV and FE_Na towards the night during rRPP days 2-4. This delay in U_NaV seems to be evoked by processes in the distal tubule.

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“…A total of 81 chronically instrumented female Beagles, about 2 years of age, and weighing 12-16 kg, were studied by standardized methods described in detail in previous papers (10,24,29,30,34,36,37). On completion of the experiments, implants were removed and the dogs were given to suitable private individuals.…”

Section: Methodsmentioning

confidence: 99%

Are large amounts of sodium stored in an osmotically inactive form during sodium retention? Balance studies in freely moving dogs

Seeliger¹,

Ladwig²,

Reinhardt³

2006

American Journal of Physiology-Regulatory, Integrative and Comp

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Alterations in total body sodium (TBSodium) that covered the range from moderate deficit to large surplus were induced by 10 experimental protocols in 66 dogs to study whether large amounts of Na+ are stored in an osmotically inactive form during Na+ retention. Changes in TBSodium, total body potassium (TBPotassium), and total body water (TBWater) were determined by 4-day balance studies. A rather close correlation was found between individual changes in TBSodium and those in TBWater (r2 = 0.83). Changes in TBSodium were often accompanied by changes in TBPotassium. Taking changes of both TBSodium and TBPotassium into account, the correlation with TBWater changes became very close (r2 = 0.93). The sum of changes in TBSodium and TBPotassium was accompanied by osmotically adequate TBWater changes, and plasma osmolality remained unchanged. Calculations reveal that even moderate TBSodium changes often included substantial Na+/K+ exchanges between extracellular and cellular space. The results support the theory that osmocontrol effectively adjusts TBWater to the body's present content of the major cations, Na+ and K+, and do not support the notion that, during Na+ retention, large portions of Na+ are stored in an osmotically inactive form. Furthermore, the finding that TBSodium changes are often accompanied by TBPotassium changes and also include Na+/K+ redistributions between fluid compartments suggests that cells may serve as readily available Na+ store. This Na+ storage, however, is osmotically active, since osmotical equilibration is achieved by opposite redistribution of K+.

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Resetting of 24-h sodium and water balance during 4 days of servo-controlled reduction of renal perfusion pressure

Cited by 21 publications

References 0 publications

Influence of Captopril on 24-Hour Balances and the Diurnal Patterns of Urinary Output, Blood Pressure, Aldosterone and Atrial Natriuretic Peptide in Conscious Dogs

Influence of Captopril on 24-Hour Balances and the Diurnal Patterns of Urinary Output, Blood Pressure, Aldosterone and Atrial Natriuretic Peptide in Conscious Dogs

Diurnal Pattern of Sodium Excretion in Dogs with and without Chronically Reduced Renal Perfusion Pressure

Are large amounts of sodium stored in an osmotically inactive form during sodium retention? Balance studies in freely moving dogs

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