Sodium Space Research Articles

Some aspects of sodium balance in the freshwater cyprinodontFundulus olivaceus

1. The freshwater cyprinodont,Fundulus olivaceus, tolerates a direct transfer from fresh water to 50% sea water and will live indefinitely in that salinity. 2. Serum sodium levels were regulated somewhat, but this was accomplished largely by expanding the sodium space. The animals remained isosmotic or slightly hyperosmotic to the environment. 3. Water permeability dropped sharply after transfer into saline solutions. 4. The animals drank only trace amounts of sea water, and drank less in 50% sea water than when in 33% sea water. 5. Sodium permeability was relatively high both in fresh water and in dilute sea water.

Regulation of water and some ions in Gammarids (Amphipods). II. Gammarus pulex.

ABSTRACT The water content, and the concentrations of sodium potassium and chloride in the blood and body water were determined in Gammaruspulex acclimatized to external salinities ranging from 0·06 mM/l NaCl up to 50 % sea water. The mean body water content remained constant at 79·0–80·3 % body wet weight. The total body sodium and chloride concentrations were lowered in 0·06 mM/l NaCl and increased markedly at salinities above 10% sea water. The normal ratio of body sodium/chloride was 1·45–1· 70, decreasing to 1·0 at 50% sea water. The total body potassium concentration remained constant at 47·5–55·2 mM/kg body H2O. The rate of potassium loss across the body surface was relatively fast. Potassium balance was maintained at an external potassium concentration of 0·010–0·015 mM/l by starved animals, and at 0*005 by fed animals. The proportion of body water in the blood space was calculated from the concentrations of potassium and chloride in the blood and in the body water. The blood space contained 38–42% body H2O in animals from fresh water. The blood space decreased to 31 % body H2O in animals from 0*06 mM/l NaCl. The sodium space was equivalent to about 70 % body H2O. The mean intracellular concentrations of sodium, potassium and chloride were estimated and the results were compared with previous analyses made on the tissues of G. pulex and other crustaceans. It was concluded that in G. pulex from fresh water the distribution of potassium and chloride ions between the extracellular blood space and the intracellular space approximately conforms to a Donnan equilibrium. 30-40% of the body sodium is apparently located in the intracellular space.

Sodium space and electrolyte excretion during the menstrual cycle

Exchangeable sodium spaces were measured at intervals during the menstrual cycle in normotensive subjects under controlled sodium intake. Urinary excretion of sodium, potassium, and creatinine was also measured daily, along with daily weights and basal body temperature. The time of ovulation was determined based upon basal temperatures and urinary excretion of pregnanediol. The results were compared to those of hypertensive subjects. No significant change was noted in sodium space during the phases of the menstrual cycle. The aldosterone secretion rates and plasma renin activity in hypertensive patients of an earlier study are also discussed.

Clinical and experimental studies on cerebral hypernatremia.

Electrolyte disturbances, especially hypernatremia, which are not uncommon in cerebral injuries or diseases, are usually attributed to water depletion and sodium retention. The authors observed hypernatremia in 9 of 37 neurosurgical patients. In 2 of them, water depletion and sodium retention were denied by the balance study and estimation of the sodium space and total exchangeable sodium, and hypernatremia was considered to be due to damage to the central nervous system itself. Experimental injury of the brain also caused hypernatremia in 3 of 44 dogs. Analysis of tissue electrolytes suggested the shift of electrolytes between intra- and extracellular compartments. Decrease of muscle sodium was comfirmed in these patients, while bone sodium did not change. Release of muscle sodium was regarded as contributing to hypernatremia.

A method for simultaneous electrolyte investigations in man using 77Br, 43K and 24Na

The different gamma energies of 24Na, 43K and 77Br allow analysis of mixtures of the three isotopes without any previous separation procedure, by gamma counting under three different conditions. A computer programme is used to perform the calculations. 77Br and 43K are cyclotron produced isotopes with half lives of 56 hr and 22·4 hr respectively. The principle gamma-ray emissions are at 240 keV and 520 keV for 77Br and at 373 keV and 619 keV for 43K. The radiation dose to the patient due to 77Br is 0·3 mrad./μCi compared with 1·4 mrad./μCi for 82Br; the dose due to 43K is 0·6 mrad./μCi compared with 0·85 mrad./μCi for 42K. In vitro experiments show that mixtures of the three isotopes can be analysed with an error of less than 2 per cent. The method is applied for simultaneous estimation of extracellular fluid volume, sodium space, exchangeable sodium and exchangeable potassium. The results are compared with a resin separation method and the findings in 10 subjects without electrolyte disorders are presented.

Long-term changes in gross body composition of paraplegic and quadriplegic patients.

1. The body composition of groups of 14 paraplegic and six quadriplegic patients were compared with those of groups of other chronically ill patients, judged clinically to be either ‘Weil-nourished’ or “poorly-nourished’. The spinal-cord injured patients had values of sodium space (expressed relative to body weight or lean body mass) similar to those of the poorly-nourished group, while in nine other parameters of body composition they resembled a well-nourished group of patients. The increased sodium space in the spinal-cord injured patients is consistent with erosion of their lean body mass. 2. The changes in body composition of three quadriplegic and four paraplegic patients were followed for varying lengths of time up to 51 months. Although many of the changes were significant in individual cases, there was no consistent trend in body composition. Both gains and losses of weight were observed, the largest factor in these being changes in body fat. Ten paraplegics showed a tendency to decrease their sodium space after 12 weeks of controlled dietary intake with significant changes in three cases.

Sodium balance and distribution in lithium carbonate therapy.

THE mechanism of action of the lithium ion in man remains obscure although it is being increasingly used especially in the treatment of manic-depressive disorder. In the similarity to sodium in the periodic table, its ability to substitute for sodium in medium surrounding nerves¹and muscles²in some in vitro systems and its active transport in biological systems^3,4have raised the possibility that a mechanism related, at least in part, to sodium metabolism may explain its actions. Coppen et al initially described several striking changes in electrolyte and water distribution in schizophrenic patients studied before and one week after receiving 1 gm of lithium carbonate daily.⁵These changes included an increase in total body water and extracellular fluid (ECF) volume, and a fall in 24-hour exchangeable sodium (Nae), sodium space and residual sodium (Nar). More recently, he was unable to confirm

Sodium space in fresh-water and sea-water eels

1. 1. The sodium space was measured in fresh-water- and sea-water-adapted eels after intraperitoneal injection or cardiac infusion of labelled sodium. The volume is defined as that which the total exchangeable sodium would occupy when homogeneously distributed at the concentration of that of the plasma, and is calculated from V int = Q t [ Na int ∗]t , where Q t in the total quantity of radiosodium present in the fish at time t and [Na int ∗] the corresponding radioactivity per unit volume of plasma 2. 2. The space so measured at equilibrium is independent of the site of introduction of the isotope but depends on the adaptation medium. It is 32 ml/ 100 g in sea water and 24 ml/100 g in fresh water. 3. 3. The kinetics of the filling up were studied and found to be a simple exponential function, about 2 hr being necessary for 95 per cent of the space to be filled, irrespective of the adaptation medium. 4. 4. The measurement of the sodium space when the isotope is introduced in the external medium is also considered, and the dimensions of the sodium space and kinetics of its filling up discussed.

ALDOSTERONE SECRETORY RATES IN THE NORMAL MENSTRUAL CYCLE

ABSTRACT Aldosterone secretion rates (ASR), urinary excretion of pregnanediol, urinary Na/K ratio and creatinine clearance were determined at intervals during the menstrual cycle in 13 normal women. The mean value of the aldosterone secretion rate was 140 μg/day in the follicular phase and 233 μg/day in the luteal phase (p< 0.001). This increase in the aldosterone secretion rate during the luteal phase was observed in subjects taking a diet unrestricted in sodium, as well as in 2 subjects with a controlled high intake of sodium (260 mEq/day). When ovulation was suppressed by administration of Enovid, the rise in the ASR previously observed in the second half of the cycle was abolished. No significant change was noted in total body water, 3-hr sodium space, or body weight in the 2 phases of the menstrual cycles studied. The cyclic variation in ASR must be taken into consideration when evaluating women for hyperaldosteronism.

Sodium space determinations in shock

1. 1. Sodium space determinations were conducted upon rats before inflicting a 20% full-thickness corporal burn or endotoxin poisoning (25 mg./kg. of intravenous E. coli endotoxin) and 4 hours after injury. These animals received no treatment. 2. 2. The sodium space did not increase for rats burned or given endotoxin when the space was calculated from a single initial injection of radioactive sodium. When the space was measured by a second past burn injection of radioactive sodium, however, the Na e increased 5 to 10%. 3. 3. All rats burned or given endotoxin became hypovolemic, as measured by increased hematocrit; blood pressure did not change. 4. 4. The hypovolemia attending the administration of intravenous endotoxin appeared due to sequestration of fluid within the gastrointestinal tract of the rat. 5. 5. The fluid sequestered during the hypovolemia attending burning contained sodium ions freely diffusible with the “exchangeable” sodium ions—those measured in the exchangeable sodium space.

Aldosterone secretory rates in the normal menstrual cycle.

ABSTRACT Aldosterone secretion rates (ASR), urinary excretion of pregnanediol, urinary Na/K ratio and creatinine clearance were determined at intervals during the menstrual cycle in 13 normal women. The mean value of the aldosterone secretion rate was 140 μg/day in the follicular phase and 233 μg/day in the luteal phase (p< 0.001). This increase in the aldosterone secretion rate during the luteal phase was observed in subjects taking a diet unrestricted in sodium, as well as in 2 subjects with a controlled high intake of sodium (260 mEq/day). When ovulation was suppressed by administration of Enovid, the rise in the ASR previously observed in the second half of the cycle was abolished. No significant change was noted in total body water, 3-hr sodium space, or body weight in the 2 phases of the menstrual cycles studied. The cyclic variation in ASR must be taken into consideration when evaluating women for hyperaldosteronism.

Diffusional resistance of the innermost layer of the placental barrier of the rabbit.

1. The permeability of the endothelial cell layer of the foetal capillaries of the rabbit placenta was measured by the tracer-dilution method. Isotopically labelled water, urea, chloride and sodium ions, and inulin were used. Radio-iodinated human serum albumin served as reference tracer. The measurements were made in in situ placentas of 27-29 days gestation of which the foetal circulation was perfused with homologous blood.2. The permeability of water was found to be 1.7 ml. min(-1).g(-1), the permeabilities of urea, chloride ions and sodium ions were in the range of 0.28-0.42 ml. min(-1).g(-1) and the permeability of inulin was 0.053 ml. min(-1).g(-1). These values may be underestimates, particularly the value of water.3. The approximate maternal blood space, foetal blood space, and extravascular sodium space were determined in rabbit placentas of 27-29 days gestation and found to be 0.16, 0.07, and 0.48 ml./g respectively.4. The permeabilities of the endothelial layer were compared to those published for the entire placenta and found to be far greater. The resistance to diffusion of the endothelial layer is only a small part of the total resistance to diffusion. Most of the resistance is localized in the syncytioand/or cellular trophoblasts.5. It was concluded that lipid insoluble molecules diffuse through the interstitial water spaces of the trophoblast in few, relatively wide channels but that diffusing water can make use of intracellular as well as extracellular paths.

The effects of hypothermia and insulin on the distribution of glucose in some tissues of the rat.

In fasted hypothermic rats (25 °C), after a glucose load of 1 g/kg body weight, in either the presence or absence of injected insulin (0.5 units/kg), the rate of disappearance of glucose from the blood was decreased as compared with that of normothermic rats (37 °C). Hypothermia did not change the total water content of diaphragm, rectus abdominis muscle, heart, or liver of these rats, nor did it change the sodium space of these tissues. Insulin-injected hypothermic rats did show an increase in the sodium space of the diaphragm. The glucose space of the muscle tissues was not changed by hypothermia, but was greatly increased by insulin in both hypothermic and normothermic rats. The glucose space of the liver was increased by insulin in normothermic rats, but in hypothermic rats an increase was found only when larger quantitites of insulin were injected. Intracellular glucose could not be detected in the diaphragm, rectus abdominis muscle, or heart of either normothermic or hypothermic rats in the absence of injected insulin, but was present in the liver of both. The injection of insulin caused intracellular glucose to accumulate in the diaphragm and heart of both normothermic and hypothermic rats. The level was increased by hypothermia only in the heart, suggesting that in this tissue the intracellular metabolism of glucose was decreased.

BODY COMPOSITION IN HEART DISEASE

Abstract In order to define the alterations in body composition in cardiac patients with hyponatraemic hypochloraemia, the chloride space, total exchangeable chloride, sodium space, total exchangeable sodium and total exchangeable potassium were measured in 12 subjects with hyponatraemic hypochloraemia and in 12 patients with normonatraemia. The groups were selected to be comparable with regard to average body weight, mean age and sex distribution.Statistical analysis defined the pattern of body composition in the hyponatraemic hypochloraemic group in the light of the findings in the normonatraemic group as follows: 1. A significant and parallel decrement of serum chloride and serum sodium concentrations; 2. An unchanged chloride space and sodium space; 3. A parallel decrement of total exchangeable chloride and total exchangeable sodium, although not statistically significant; 4. A normal or increased total exchangeable chloride and sodium in relation to predicted normal values; 5. A normal distribution of sodium in relation to chloride space; and 6. A significant rise in serum potassium concentration and a tendency to decrease of total exchangeable potassium.While the interrelations between chloride space and sodium space and between total exchangeable chloride and total exchangeable sodium were the same in the two groups, the ratios of Cle/Na and Nae/Cl space were significantly lowered in the hyponatraemic hypochloraemic group.It is concluded that, although it is likely that a deficit of total exchangeable chloride in relation to total exchangeable sodium, associated with metabolic alkalosis and decreased total exchangeable potassium, may account in part for the hypochloraemia seen in both groups, the major cause of the marked hypochloraemia in the hyponatraemic group is apparently a dilution of chloride in an expanded extracellular phase caused by the water retention responsible for the hyponatraemia.

THE DISTRIBUTION OF ELECTROLYTES AND WATER IN PATIENTS AFTER TAKING LITHIUM CARBONATE

The distribution of electrolytes was measured in 12 depressed and 10 schizophrenic patients before treatment and after about one week's treatment with lithium carbonate. The main findings were increases in total body-water and intracellular water and a trend towards an increase in extracellular water. Exchangeable sodium, sodium in the extracellular space, residual sodium, sodium space, and concentrations of sodium and potassium in plasma did not change significantly. In 2 of the schizophrenic patients residual sodium values were apparently negative.

Body water variations in manic-depressive psychosis.

Most of the water and electrolyte studies in mental illness have been carried out on patients suffering from periodic disorders and have been reviewed by Crammer (1962). Coppen and Shaw (1963) found increases in total body water and extracellular fluid and a decrease in residual sodium space on recovery from depression. Manic patients with a high vocal productivity were found by Anderson et al. (1964) to have a negative sodium balance, low plasma potassium levels and a positive potassium balance. Depressed patients with a low vocal productivity had a reduced rate of sodium loss and higher plasma potassium levels. Dawson et al. (1956) found extracellular expansion on spontaneous recovery from manic or depressive attacks. The purpose of the present study was to investigate variations in total body water and its distribution in manic-depressive psychosis. The investigation was complementary to a similar study of variations in body composition during recovery from depression reported by Hullin et al. (1967).

Variations in body water during recovery from depression.

Reports of significant changes in water and electrolytes during recovery from depression may provide insight into important physiological factors in depressive illnesses. Brownet al.(1963) demonstrated an increase in the extracellular fluid volume in 22 of 28 patients suffering from primary depressive disorders treated with E.C.T. or imipramine. The findings of these authors, which were discussed in relation to previous work on sodium metabolism and water balance in depressive disorders, were thought to support the idea of a shift of fluid from intracellular to extracellular spaces during the response to treatment. Coppen and Shaw (1963) found an increase in total body water, extracellular fluid and a decrease in the residual sodium space on recovery from depression.

An upper limit to the number of sodium channels in nerve membrane?

1. A small volume of artificial sea water containing 300 nM tetrodotoxin (TTX) was applied successively to seven lobster nerve trunks and the cumulative uptake of toxin investigated by bio-assay.2. Light and electron microscopy indicated that the nerve trunks had a total axonal area of 0.7 x 10(4) cm(2)/g.3. Sodium analysis gave a sodium space for the nerve trunks of 30%.4. The amount of toxin taken up by the cells in 1 g of nerve is less than 1.6 x 10(-11) moles.5. It is argued that there are probably fewer than 13 sodium channels/mu(2) axon in lobster nerve.

The effect of aldosterone on sodium and potassium distribution in man.

SUMMARY Total exchangeable sodium, potassium and bromide space were measured by a triple isotope technique, and antipyrine space, body weight, plasma electrolyte concentrations and urine electrolyte excretion were determined before and after intramuscular injection of 0·5 mg. aldosterone 6-hourly for 6–8 days in nine convalescent men. After the treatment with aldosterone there were mean increases in body weight of 2·5 kg., 2·5 1. in total body water, and of 3·0 1. in extracellular fluid volume; a slight decrease in intracellular fluid volume was not significant. The mean total exchangeable sodium increased by 463 m-equiv. and the mean cumulative urinary excretion of sodium decreased by 444 m-equiv. The sodium was retained in the extracellular fluid without significant change in exchangeable intracellular sodium. Mean total exchangeable potassium was reduced by 207 m-equiv. while mean cumulative urinary potassium excretion increased by 88 m-equiv. The potassium loss was entirely intracellular. The main source of error arose from isotope counting. The coefficient of variation of the sample count minus the background exceeded ±3% in 18 out of 150 samples: these results were discarded. Sixteen of the inaccurate counts were due to low concentrations of sodium or potassium in the specimens.

The extracellular space of the lens

The extracellular space of rat, rabbit and calf lenses has been estimated in vitro using radioactive non-metabolized carbohydrates and 24 Na as test substances. The size of the extracellular space ranges from 4 to 13% of the lens water, depending on the test substance used. In addition, the extracellular space of the lens in situ was estimated from chemical determination of the sodium content of aqueous humor and of the lens. This sodium space, presumably the maximal size of the extracellular space, is from 10 to 13% of the lens water, depending upon the animal studied. The sucrose space of the rat lens was found in vivo to be about 5%.