Fluid Volume Distribution Research Articles

Body composition and its relation to systemic haemodynamics, fluid volume partitions and energy utilization in rats with bilateral ventromedial hypothalamic lesions.

Body composition and its relationship with intra-arterial pressure, fluid volume partitions and oxygen consumption were studied in male rats four months following ventromedial hypothalamic (VMH) destruction during the static phase of the development of obesity. Compared with sham-operated controls, rats with VMH lesions had a greater body weight which was related to an increased body lipid content and an elevated arterial pressure and total peripheral resistance. Fluid volume distribution was normal and total body oxygen consumption (per unit of body weight) was reduced. Bilateral destruction of the ventromedial hypothalamus was confirmed in each of the rats studied and no relationship could be demonstrated between the lesion size and the magnitude of haemodynamic changes. It is concluded that the increased arterial pressure observed in obese VMH lesioned rats was directly related to an elevated total body lipid content.

BODY FLUID VOLUMES AND PRESSOR RESPONSE TO ANGIOTENSIN II AND NOREPINEPHRINE IN PREGNANT RATS

The aims of the present study were to examine the appropriateness of the rat as a model for human pregnancy in distribution of body fluid volumes and pressor response to vasoconstrictor substances. Body fluid volumes and the pressor response to angiotensin II (AII) and norepinephrine (NE) were determined in unanesthetized nonpregnant and pregnant rats, at 6-10 days gestation (early gestation) and 16-20 days gestation (late gestation). The distribution of body fluid volumes was measured by an isotope dilution method; plasma volume (PV), extracellular fluid volume (ECFV), and total body water (TBW) by 131I-radio-iodinated serum albumin, 35S-sodium sulfate, and tritiated water respectively. Late gestation rats had signficantly (p<0.01) increased PV and TBW but only slight increased ECFV when compared to nonpregnant rats, while the pregnant rats had elevated PRA values (p<0.01). The results are almost compatible with the data in human pregnancy. In early gestation, the pressor response to AII tended to decrease, while that to NE was found to be almost the same with that in nonpregnant rats. In late gestation, on the other hand, the pressor response to both AII and NE decreased significantly (p<0.05) compared with nonpregnant rats. The reduced AII pressor response in late gestation decreased further by the treatment with indomethacin (10mg per kg), while response to NE increased significantly (p<0.05) to the normal level in nonpregnant rats. The treatment did not alter the response to AII and NE in either nonpregnant or early gestation of rats. PRA was measured in other groups of unanesthetized pregnant and nonpregnant rats before and after the treatment with indomethacin. PRA values were significantly (p<0.05) elevated both in early and late gestation rats compared with nonpregnant rats before the treatment. The treatment did not change PRA values either in nonpregnant or early gestation rats, but increased them in late gestation rats. These results suggest that the mechanisms of reduced pressor response to AII and NE in late gestation rats might be different : the response to AII is mainly determined by the increased activity of the renin-angiotensin system, and that to NE might be related to increased vasodilator prostaglandins. The rat could serve as another animal model in investigating AII and NE refractoriness in pregnancy.

Disturbances in Haematology, Fluid Volume Distribution and Circulatory Function Associated with Low Environmental pH in the Rainbow Trout,Salmo Gairdneri

ABSTRACTExposure of adult rainbow trout to low pH (4·0–4·5) for 3 days resulted in progressive increases in heart rate, mean arterial blood pressure and haematocrit. The haematocrit increase resulted from erythrocyte swelling, a reduction in plasma volume and a mobilization of erythrocytes from the spleen. Erythrocyte swelling probably resulted from plasma acidosis and a reduction in plasma ions (McDonald &amp; Wood, 1981). There was an associated redistribution of body water from extracellular to intracellular compartments, but maintenance of total body water content. Erythrocyte mobilization was reflected in an increase in reticulocyte and erythrocyte counts, and a depletion of splenic blood reserves. Haemoconcentration caused large increases in blood viscosity, which contributed to the rise in blood pressure. Pharmacological analysis revealed an adrenergic component to the cardiovascular disturbance. These events are thought to play a key role in the toxic syndrome.

Effect of hemodialysis on blood volume distribution and cardiac output.

Effects of hemodialysis on extracellular fluid volume distribution, left ventricular volumes, and cardiac output were determined in patients with end-stage renal disease (n = 19). Distribution of extracellular fluid loss from hemodialysis differed widely among patients, so that weight change correlated weakly with contraction of total blood volume (index of determination 29%, p less than 0.05). End-diastolic volume (EDV) decreased from 150 +/- 49 ml (mean +/- SD) to 118 +/- 42 ml, p less than 0.001; stroke volume (SV) decreased from 108 +/- 36 to 86 +/- 33 ml (p less than 0.001) without change in ejection fraction (from 0.73 +/- 0.09 to 0.74 +/- 0.11). A significant correlation was found between total blood volume (TBV) and EDV before (r = 0.66, p less than 0.005) and after dialysis (r = 0.61, p less than 0.001). The correlation between TBV and SV was highly significant before (r = 0.78, p less than 0.001) and after dialysis (r = 0.66, p less than 0.005), but there was no correlation between change in TBV and change in EDV or in SV. The ratio of EDV to TBV (EDV/TBV x 100) was reduced significantly from 3.49 +/- 0.92 to 3.06 +/- 0.97, p less than 0.001). There results suggest that, although intravascular volume was the major determinant of cardiac output in dialyzed patients, the postdialysis reduction in cardiac output might be related more to the relocation of blood volume than to the absolute degree of blood volume contraction.

Lack of nonexcretory renal influences on hemodynamics and fluid volume distribution after the volume loading of conscious dogs.

HomeCirculation ResearchVol. 46, No. 6Lack of nonexcretory renal influences on hemodynamics and fluid volume distribution after the volume loading of conscious dogs. Free AccessAbstractPDF/EPUBAboutView PDFSections ToolsAdd to favoritesDownload citationsTrack citationsPermissions ShareShare onFacebookTwitterLinked InMendeleyReddit Jump toFree AccessAbstractPDF/EPUBLack of nonexcretory renal influences on hemodynamics and fluid volume distribution after the volume loading of conscious dogs. R D ManningJr R D ManningJrR D ManningJr Search for more papers by this author Originally published1 Jun 1980https://doi.org/10.1161/01.RES.46.6.880Circulation Research. 1980;46:880–886 Previous Back to top Next FiguresReferencesRelatedDetailsCited By Koomans H, Braam B, Geers A, Roos J and Dorhout Mees E (1986) The importance of plasma protein for blood volume and blood pressure homeostasis, Kidney International, 10.1038/ki.1986.248, 30:5, (730-735), Online publication date: 1-Nov-1986. Manning R, Cowley A and Coleman T (1985) Effects of baroreceptor denervation on volume loading hypertension in anephric dogs., Hypertension, 7:4, (562-568), Online publication date: 1-Jul-1985. Manning R and Guyton A (1982) Control of blood volume Reviews of Physiology, Biochemistry and Pharmacology, Volume 93, 10.1007/BFb0032669, (69-114), . June 1, 1980Vol 46, Issue 6 Advertisement Article InformationMetrics Copyright © 1980 by American Heart Associationhttps://doi.org/10.1161/01.RES.46.6.880 Originally publishedJune 1, 1980 PDF download Advertisement

Dynamics of fluid distribution between the blood and interstitium during overhydration.

The dynamics fluid volume distribution between the blood and interstitium was studied in 24 anephric conscious dogs by making serial measurements of blood volume, sodium space, and plasma proteins during several different states of hydration. After recovery from splenectomy and unilateral nephrectomy, the remaining kidney was removed, and intravenous infusion of lactated Ringer solution equivalent to 5%, 10%, or 20% of the body weight followed the next day. Blood volume and sodium space were elevated in each infusion group for the entire 25-h postinfusion period of measurements, while total amount of circulating proteins increased in the 10% group and decreased in the 20% group, which blunted the increase in blood volume in this group. During the first 5 h after infusion, the increase in blood volume was proportional to the increase in sodium space up to a sodium space of 50% above control. By 24 h postinfusion the relationship between blood volume (BV%) and sodium space (SS%) as percent control was linear over the entire range of sodium spaces (BV% = 68.0 + 0.32 SS%, r = 0.99).

Fluid volume distribution within superficial shell tissues along body axis during changes of body posture in man: the application of a new miniature plethysmographic method.

In up to six different sides along the body axis during tilting manoeuvres, volume shifts into or out off superficial tissues were followed with a newly developed miniature plethysmograph. It was possible to localize a region where no or only minor volume changes during the tilt table experiments occurred. This region is identical with the Hydrostatic Indifferent Point (HIP) being localized below the apex of the heart in the upper third of abdominal vena cava. Above the HIP fluid is drained out off the tissues during assumption of upright posture whereas below the HIP fluid volume is pooled. The volume changes occurred in two phases. Within the first 5 s in the cephalad parts of the body a rapid decrease occurred, thereafter the volume remained unchanged or even increased; below the HIP within the first 5 s a large volume increase was followed by a slow continuous volume increment. The functional peculiarities of the low pressure system as a whole were visible studying only superficial shell tissues of the body with the non invasive miniature plethysmographic technique.

Extracellular fluid distribution in rats with chronic one- and two-kidney Goldblatt hypertension.

1. The influence of the intact kidney on blood pressure, extracellular fluid volume (ECF, ferrocyanide space) and ECF volume distribution was studied in rats 60 days after constriction of the contralateral renal artery. 2. Renal artery constriction increased both blood pressure and ECF levels. The rise of both variables was more pronounced in rats with the contralateral kidney removed (one-kidney rats) than with the contralateral kidney intact (two-kidney rats). 3. The interstitial fluid volume increased similarly in both experimental groups, the more pronounced ECF increase in the more severly hypertensive one-kidney rats being due to increased plasma volume. In the less hypertensive two-kidney group the plasma volume was not increased significantly but correlated positively with the blood pressure levels. 4. The plasma volume/interstitial fluid volume ratio was decreased in the two-kidney group but did not differ from control values in the one-kidney group thus resembling the ECF partition reported in the hypo-and hypervolaemic type of essential hypertension, respectively. 5. It is suggested that the antihypertensive influence of the intact kidney may be partly due to its ability to escape from the sodium-retaining mechanism activated by renal artery stenosis, which determines the degree of plasma volume expansion and, in connection with this, also the degree of blood pressure elevation.

On the regulation of the renal response blood volume expansion by vascular parameters in the rat.

The dynamic patterns of body fluid volume distribution, of cardiovascular variables and of renal water, sodium and potassium excretion were studied in the anaesthetized rat following acute, iso-oncotic blood volume expansion. The increased renal excretion following expansion was soon reversed and its pattern to termination was not correlated with changes in pulse and mean arterial pressure, in plasma electrolyte concentration or in haematocrit. At the end of the renal response the change in extracellular fluid volume was not usually corrected, the blood volume was always well above its control value and the interstitial fluid was below its control value. In all cases the temporal pattern and the termination of the renal response corresponded closely with the temporal pattern and the return to the control value of the central venous mean and pulse pressure. The findings of thse experiments are not consistent with the view that any of the measured body fluid volumes directly and always determine renal excretion. It is proposed that in response to an acute blood volume expansion an animal may initially regulate neither its blood volume nor its extracellular fluid volume but rather a factor which is reflected in or related to the central venous pressure.

Studies on the experimental alteration of water and electrolyte composition of the eel (Anguilla anguilla L.).

SUMMARY The distribution of water, electrolyte composition (Na, K, Ca, Mg, PO4, Cl) and extracellular fluid volume of eels (Anguilla anguilla L.) were investigated under different experimental conditions. Adrenalectomy of the freshwater eel was followed by an increase in body weight, a fall in the amount and concentration of sodium in serum and muscle and a shift of water into the cells. The concentration of serum potassium remained within the normal range. Adrenalectomy of the sea-water eel was followed by a decrease in body weight and an increase in the concentration of extra- and intracellular sodium. The concentration of serum calcium also increased, that of potassium remained within the normal range but the actual content diminished. Removal of the corpuscles of Stannius from the freshwater eel gave some effects similar to adrenalectomy. There was, however, no significant increase in body weight but the concentrations of serum potassium and calcium rose. Removal of the corpuscles from the sea-water eel brought about changes similar to, but less pronounced than those after adrenalectomy. The results of the injection of mammalian corticotrophin, cortisol, aldosterone and anti-aldosterone compounds are given. They are discussed in the light of the possible roles of the adrenal cortex and the corpuscles of Stannius in the maintenance of homeostasis of the eel in different environments.