Isotonic NaCl Solution Research Articles

Osmosensitive neurons in the rat's dorsal midbrain

In experiment 1, multiple unit recordings were taken simultaneously from lateral preoptic and dorsal midbrain areas during a series of intracarotid hypertonic and isotonic NaCl injections. Subjects were 15 hooded rats (11 males and 4 ovariectomized females) under urethane anesthesia. Results showed that the neuronal reactions to a series of hypertonic NaCl injections (0.30 M, 0.45 M, 0.60 M and 0.75 M) were at least as strong in the dorsal midbrain as in the lateral preoptic area. Strength of neuronal reaction correlated with osmolarity of the NaCl solution injected. Control isotonic NaCl injections were ineffective, and the (monitored) force of injection was found not to affect the results. In experiment 2 with 15 hooded rats (9 males and 6 ovariectomized females), and two male Wistar rats under urethane anesthesia, recording from dorsal midbrain units were made during intracarotid injections of hypertonic and isotonic NaCl solutions. In addition, other sensory stimulations, including tail pinches, were presented. Of the 52 units studied, 39 cells (75%) reacted to injections of hypertonic NaCl, but not the isotonic (control) solution (Normosol-R). Again, strength of neuronal reaction correlated with osmolarity of the NaCl solution injected, and force of injections was found not to influence results. Eleven cells reacted to hypertonic NaCl injections but not to tail pinch. This and other evidence indicated that certain dorsal midbrain cells were specifically osmosensitive, and not merely showing general 'arousal' reactions to the injections. These results indicate that, for the rat, the osmosensitive zone extends into the midbrain. The functional significance of these findings is discussed.

Effect of drugs on human erythrocytes. I. Morphological changes and increase in fragility of erythrocytes treated with drugs.

To clarify the mechanism of hemolysis of human erythrocytes at higher drug concentrations, the effect of some drugs on osmotic and heat fragility, K+ efflux from the cells and morphological changes of the cells were studied. As a result of these studies, it was found that chlorpromazine and clemastine at 10-5M caused partial swelling, at 10-4M changes in cell shape to a sphere and at above 4×10-4M, at which the hemolysis is initiated, shrinkage and sinking of the cells. The mean cell volume of the cells increased by 4-5% at 5×10-5M and 8-9% at 10-4M. The cell volumes assumed at which concentration the hemolysis is initiated with drugs were 114-115% for these drugs. The initial swelling and subsequent shrinkage of the cells induced with drugs were found to be more predominant in concave portions of the cell membrane than in portions of the rim by scanning electron microscopic studies. The cell exposed to drugs at higher concentrations, at 5×10-5 and 10-4M, increased osmotic and heat fragility and the increased fragility was not reduced by washing and subsequent incubation in isotonic NaCl solution, in contrast with their stabilizing effect and their reversibility at the low concentrations. Efflux of K+ from the cells exposed to drugs was found to increase far more readily than that of hemoglobin.

Coupling of water to solute movement in isolated gastric mucosa.

Osmosis is apparently the mechanism responsible for the coupling of water to solute transport in biological membranes. Often a secreted or absorbed fluid is essentially iso-osmotic with the solution of origin, or with plasma, and various models have been constructed by Curran, Diamond and others to account for such observations. More information is needed, however, to test further the predictions of these models and to facilitate correlation with known structural details. This study deals with gastric secretion and the effects of the luminal solution on its composition. Although pure gastric juice collected in vivo is virtually iso-osmotic with plasma, Teorell, Obrink and others found that instillation of a buffer solution (glycine) in the lumen led to a twofold increase in the concentration of gastric acid. This effect is not restricted to buffer solutions: the normality of H+ secreted into an isotonic (120 mM) NaCl solution bathing the isolated bullfrog gastric mucosa was 276 +/- 19 mmol/1 (13 experiments). Clearly the luminal solution affects the concentration of gastric secretion, probably by reducing an endogenous osmotic gradient. Thus the sites responsible for transport of H+ must be accessible from the luminal solution.

Diabetogenic effect and inhibition of insulin secretion induced in normal rats by ammonium infusions.

In order to explain the abnormalities of glucose metabolism previously observed in patients with blood ammonia elevation, the effect of a transitory hyperammonemia on I.V. glucose tolerance was investigated in rats. An I.V. glucose tolerance test was performed in 3 groups of 15 rats 60 min after the beginning of a 95 min infusion of either a 2 ml isotonic NaCl solution (control group) or ammonium acetate solutions at low (0.50 mumol/kg/min. NH4+) or high doses (1.70 mumol/kg/min NH4+). The "high" NH4+ infusion produced an increase of blood ammonia to levels near 1000 mug/100 ml, a significant decrease in the K coefficient for glucose disappearance (2.53 X 10(-2) +/- 0.20 compared to 4.92 X 10(-2) +/- 0.13 in control group) and a suppression of the radioimmunological plasma insulin (I.R.I.) response to glucose. With the "low" NH4+ infusion the hyperammonemia was less pronounced (200-300) mug/100 ml), but the decrease in K(3.02 X 10(-2) +/- 0.15) and in the first phase of I.R.I. release remained significant. The decrease in glucose disappearance rate could be accounted for by the proportional decrease in insulin secretion. Thus glucose intolerance induced by ammonium acetate infusions may be due to a direct effect of NH4 + on the pancreas. These abnormalities in glucose metabolism depend on the quantity of infused ammonium.

Gonadectomy and the development of age-dependent polydipsia and the intake of NaCl solutions in the SWR/J mouse

Gonadectomies were performed at 25 days of life in SWR/J mice, a strain known to develop age-dependent nephrogenic diabetes insipidus with females drinking far more than males. Effect of gonadectomy was different for each of the 3 nonreproductive behaviors studied. (1) Ovariectomy reduced the age-dependent polydipsia seen in females, but castration was without effect in males. (2) Castration of males resulted in a lower intake of an isotonic NaCl solution, making the castrated males similar to the sham-operated and ovariectomized females, which did not differ. (3) For the short-term activity measurement sham-operated males did not differ from sham-operated females and castrated males did not differ from ovariectomized females. In each sex, gonadectomy reduced activity.

Increased inulin absorption from the cat stomach exposed to acetylsalicylic acid.

AbstractPolydisperse 14C‐inulin was absorbed from the stomach of the cat when 15 mM acetylsalicylic acid, mainly in the unionized form, in isotonic NaCl solution, was also present in the lumen. The absorbed inulin was rapidly excreted and accumulated in the urine in sufficient quantities for molecular weight distribution analysis. The latter showed that about 95 percent of the urinary inulin had a molecular weight greater than 2000 and that only moderate molecular sieving of the instilled inulin (weight average molecular weight 5200) occurred. This means very probably that larger molecular species than tested here could be absorbed from the stomach. The instillation of 14C‐inulin in acetylsalicylic acid‐free isotonic NaCl, however, also resulted in a smaller but significant inulin absorption. The latter was further considerably reduced if the inulin was not added together with the isotonic saline, but later (20 min) in a small liquid volume. This suggests that mere distension of the stomach causes a temporary increase of the permeability which, however, is much smaller than that after acetylsalicylic acid. It may be relevant that acetylsalicylic acid was found here to increase gastric absorption of saccharide molecules of a size earlier reported to be sufficiently large to evoke immune reactions.

Age-dependent polydipsia in the SWR/J mouse

Both absolute water intakes (ml) and relative water intakes (ml/100 g body weight) increased with age in the SWR/J mouse. This age-dependent polydipsia was more pronounced in the females than in the males. The polydipsia was abolished by food deprivation and by giving a 20% sucrose solution in place of water. Intakes of polydipsic mice were elevated still further by offering 5% sucrose and 0.2% and 0.5% saccharin. The well-defined circadian rhythm of drinking in this strain was not altered by the development of polydipsia. In females, the increase in water intakes was accompanied by a decrease in intakes of isotonic and hypertonic NaCl solutions in a single tube test. It is suggested that the SWR/J mouse might provide a model for the study of behavioral changes accompanying age-dependent renal deterioration.

Inhibition of natidiuretic hormone secretion by intracarotid infusions of slightly hypertonic non-electrolyte solutions.

ABSTRACT Relatively rapid (3.75 ml/min), unilateral intracarotid infusions of slightly hypertonic (0.35 m) galactose and glycerol solutions induced a water diuresis within 40 to 60 min in the non-hydrated goat. The response to equi-osmolal fructose solution was weaker and less consistent. The water diuresis was apparently due to an inhibition of the basic ADH secretion, since it could be inhibited temporarily by the administration of small amounts of arginine vasopressin. The corresponding intracarotid infusion of isotonic NaCl solution did not significantly alter the renal clearance of free water, nor did equivalent intrajugular infusions of the non-electrolyte solutions induce water diuresis. The results appear incompatible with the osmoreceptor theory, and support the assumption that a central, Na+ sensitive receptor system may be involved in the regulation of the ADH secretion.

Licking rate of rats is reduced by intraduodenal and intraportal glucose infusion

The effect of isotonic glucose, urea, and NaCl solutions (0.5 ml) delivered directly to the duodenum or portal system on the rate of drinking a 3.2% glucose or a 3.4% sucrose solution was investigated in rats. Both duodenal and portal glucose infusions produced a decrease in licking rate when the licking test vas administered immediately after the infusion. The effect diminished with increasing time intervals between the infusion and the test. Infusions of urea by both the duodenal and portal routes had effects similar to those produced by glucose but the magnitude of the effect was smaller. Control infusions of isotonic NaCl into the portal vein indicate that the depressing effect of portal glucose and urea on licking rate was chemospecific rather than due to local hypervolemia. Intrajugular infusions of glucose did not alter lick rates, suggesting that the chemoreceptors involved in the effects produced by portal infusions are located in the liver.

Effects of various ionic media on extraction of soluble nuclear proteins and on nuclear ultrastructure

Isolated liver nuclei were extracted 3 times at pH 7.2 with solutions containing either (1) monovalent cations, (2) both mono- and divalent cations, or (3) sucrose solutions containing only divalent cations. The extracted proteins were analysed by two-dimensional acrylamide gel electrophoresis and the ultrastructural alterations of the treated nuclei were examined by electron microscopy. The solutions containing Na + or K + monovalent and Ca 2+ and Mg 2+ divalent ions extracted the same amount (18–22 %) of the nuclear proteins. The two-dimensional gel electrophoretic patterns of these extracts were nearly identical and the structures of the nuclear components were well preserved even after 3 times repeated extractions. The solution containing only Na + extracted less protein (14–15 %) than the solutions containing both mono- and divalent cations. Extraction with isotonic NaCl solution altered the nuclear and nucleolar morphology; unlike the other solutions employed, this solution extracted some DNA and histones. The isotonic sucrose solution containing only divalent cations extracted less protein than the other solutions (9–11 %) and produced marked condensation of the chromatin. These analytical and electron microscopic studies showed that mono- and divalent cations play a role in structural organization of chromatin.

The amphiphatic nature of Prymnesium parvum hemolysin

1. 1. Prymnesium Toxin behaves as a surface-active agent and forms aggregates above the critical concentration of 0.6 ng/ml in isotonic NaCl solution. 2. 2. Factors affecting the critical micelle concentraion of surface-active agents, such as concentration, temperature and solvents were tested for their effect on the hemolytic activity. Above concentrations of 30 μg toxin/ml in methanol, the increment of hemolytic activity is much greater than the increment in the toxin concentration and they bear no fixed relation to one another. This effect can be reversed to prolonged incubation of the titrated toxin before addition of erythrocytes. After preincubation at −10 °C, aqueous or organic solutions of the toxin show a more than 20-fold increased activity. The cold activation is also reversible and disappears when the toxin is kept at 20 °C for 10 min before titration. 3. 3. The addition of organic solvents to an aqueous solution of the toxin considerably increases the hemolytic activity. 4. 4. The possibility that the toxin aggregates rather than the monomers are the active hemolysin is discussed.

Evidence for the osmotic flow across dog submaxillary gland epithelia as a cause of salivary secretion.

In order to clarify the nature of the secretory process of water in dog's submaxillary glands, the following experiments were carried out:(1) measurement of the secretory pressure, (2) measurement of osmolarity of saliva secreted against a high intraluminal pressure, and (3) observation of the effect on the intraluminal pressure of retrograde injection of a hypertonic sucrose solution or an isotonic NaCl solution. It was found that when the secreted saliva was lead to a vertical polyethylene tube the secretion continued until the salivary column reached a height of more than 350 cm with continuous stimulation of the chorda tympani. The osmotic pressure of saliva was examined when it was secreted by stimulation of the chorda tympani into a closed luminal system with a pressure transducer. Under the influence of high luminal pressure (250 mmHg), the osmotic pressure was found to be 350 mOsm, the value being significantly hypertonic as compared with serum. By using the equation ΔP=δRTΔC, which is applicable to the gland system under zero flow conditions, the value of a of the system for salt (probably NaCl) was calculated to be about 0.23. From these findings, it is concluded that the osmosis across some parts of the gland, probably the acinus and the intercalated duct, is very important in water secretion of dog's submaxillary glands, as proposed in the osmotic flow model of Lundberg, Petersen, and Slegers and van't Hof-Grootenboer.

Effects of temperature, medium K +, ouabain and ethacrynic acid on transport of electrolytes and water by separated renal tubules

1. 1. Isolated tubules from rabbit renal cortex are loaded with Na +, Cl −, water and leached of their K + by incubation at 0.5°C in a K −-free medium. Three aliquot fractions of the preparation are incubated: at 0.5 °C in a K +-free medium, at 28 °C in a K +-free medium, at 28°C with 5 mM,[K +] 0, respectively. The incubation at 0.5 °C is used as a control. The tubules incubated at 28 °C, K +-free, lose an isotonic NaCl solution and maintain nearly their whole K +. Those incubated at 28 °C with 5 mM [K +] 0, gain K + and lose water, Na + and Cl − in such a way that the increase of the K + intracellular concentration is exactly balanced by the decrease of the Na + plus Cl − intracellular concentrations. 2. 2. Both extrusion of Na + (with Cl and water) from leached tubules, incubated at 28°C in a K +-free medium, and exchange of Na + for K + in leached tubules rewarmed with 5 mM [K +] 0, are completely inhibited by ouabain and ethacrynic acid, which simultaneously induce an important K + tissular depletion. 3. 3. When leached tubules are incubated at 0.5 °C or 28 °C in K + free medium, small amounts of this ion appear in the incubation medium. Tubular leakage is likely to account for these traces of K +. Incubation of leached trubules in a K +-free medium (except for tracer 42KCl) induces a rapid exchange of tissular K + for medium K + at 28 °C, and a much smaller one at 0.5 °C. 4. 4. When recapture of the escaped K + is partially prevented by dialysis of tubules suspension against a K +-free medium, the K + tissular content is significantly reduced as well as the extrusion of Na +, Cl − and water. 5. 5. It is concluded that both the net efflux of Na − (with Cl − and water) induced by the rewarming of leached tubules into nominally K +-free solutions, as well as the Na +−K + exchange, demand the simultaneous movement of K + into the cells. It is further concluded that ions and water transport by renal tubular cells is governed in some manner by cell electrolyte composition.

The interactions of fibrinogen and dextrans with erythrocytes.

1. The rate of packing of erythrocytes in whole blood, under a centrifugal field of 200 g, has been studied using an automatic recording centrifuge.2. Reduction of the supernatant fibrinogen concentration, by repeatedly washing the cells, lowers the rate of packing and reduces the cell flexibility.3. Resuspending the cells in their own plasma or in isotonic solutions containing fibrinogen restores their flexibility.4. Rouleaux formation has been shown to have no effect on the rate of packing by comparison of blood diluted with plasma, isotonic NaCl or Ringer-Locke solutions. While the degree of rouleaux formation varied with the diluent used, the rate of packing and packed cell haematocrit were the same, for the same dilution.5. Both formalin and dextran altered the degree of rouleaux formation and reduced erythrocyte flexibility. Dextran was found to act indirectly on the erythrocyte flexibility by reducing the plasma fibrinogen concentration.

BLOOD BRAIN BARRIER: IMPLICATION OF DRUG METABOLISM IN THE PENETRATION OF METHYLHYDROXYCOUMARIN IN RAT

It is generally believed that apolar substances, by their lipotropic virtue, penetrate through biological membranes and distribute widely in the body, whereas polar substances have limited access to the central nervous tissue. Thus, the term blood brain barrier is designated to describe a lipid-containing membrane or barrier which limits the accessibility of polar substances to the brain. This concept holds well in most cases. In a few instances, however, fairly liposoluble substances such as morphine (1, 2) demonstrate a low distribution to the brain. On the other hand, we have observed that chlorpromazine sulfoxide, a polar substance, was found in the brain in a substantial amount following an intraperitoneal injection to rats, even after a rigorous perfusion of the brain with hypertonic as well as isotonic NaCl or KCl solutions (unpublished observations). These facts raised the question whether liposolubility per se is the sole factor determining the permeability of a drug through a blood brain barrier.

Blood brain barrier: implication of drug metabolism in the penetration of methylhydroxycoumarin in rat.

Abstract It is generally believed that apolar substances, by their lipotropic virtue, penetrate through biological membranes and distribute widely in the body, whereas polar substances have limited access to the central nervous tissue. Thus, the term blood brain barrier is designated to describe a lipid-containing membrane or barrier which limits the accessibility of polar substances to the brain. This concept holds well in most cases. In a few instances, however, fairly liposoluble substances such as morphine (1, 2) demonstrate a low distribution to the brain. On the other hand, we have observed that chlorpromazine sulfoxide, a polar substance, was found in the brain in a substantial amount following an intraperitoneal injection to rats, even after a rigorous perfusion of the brain with hypertonic as well as isotonic NaCl or KCl solutions (unpublished observations). These facts raised the question whether liposolubility per se is the sole factor determining the permeability of a drug through a blood brain barrier.

Studies in the Mitochondria of <i>Allomyces</i> Butler

Mitochondria of the two species of Allomyces, viz., A. javanicus, and A. moniliformis were investigated. Various forms of mitochondria were present in varying proportions. In isotonic solutions of NaCl, the mitochondria disintegrated into granules, but in hypertonic saline solution cells were plasmolysed at first but recovered later on. Mitochondria in such cells changed their shape, fragmented, became vesiculated and disappeared. In 0.5M sucrose solution, they quickly fragmented into small spheres, averaging 1 micron in diameter. Temperature of 10°±1° to 45°C had seemingly no effect on mitochondria. At higher temperatures, viz., 50°C, the mitochondrial movement ceased and at 75°C they broke up into beads and disappeared.Mitochondrial orientation was determined by the direction of cytoplasmic streaming. Small granules as normal mitochondria were stained red after 48 to 72 hours with tetrazolium chloride of 0.005 per cent concentration. Higher concentrations were lethal. Mitochondria were stained supravitally with Janus green B Hoechst as sky blue colour and reduction of the dye was observed after sometime. Amongst all the fixatives tested, Regaud's formol-bichromate was found to be the most successful.

Effect of angiotensin and atropine on the spontaneous release of acetylcholine from cat cerebral cortex

The effect of angiotensin and atropine was studied on cortical acetylcholine output in the cat ‘encéphale isolé’ preparation. Acetylcholine was estimated by bioassay. Local administration of either of these 2 drugs at a concentration of 10 −9 M caused an increase of acetylcholine output from the parietal cortex, an effect that persisted after washing. At 10 −8 M, angiotensin caused a 240% increase of acetylcholine output, while atropine, at the same molar concentration, did not change the initial output of acetylcholine. Intracortical administration of 1 ng og angiotensin also increased the acetylcholine output (85%), while a same volume of isotonic NaCl solution did not change the initial output. Brain cholinesterase activity, as measured by the gazometric method, was not depressed by angiotensin. It is postulated that the effect of angiotensin on acetylcholine output is due to changes in the release mechanism.

Some aspects of lymph production in the rat.

SummaryThese in vivo studies were made possible by a modification of Bollman's technique for the cannulation of the abdominal thoracic duct of the rat. Thus, by combining a thoracic duct fistula with a stomach fistula, the influence of several substances on lymph flow was studied. Infusion with an isotonic solution of NaCl has a marked influence on lymph flow but it is not diuretic. Protein, carbohydrate, triglyceride, vasopressin, oxytocin, and Doca increased lymph flow only when accompanied by infusion with saline. Triglyceride emulsions had a pronounced lymphagogic effect even without infusion with saline. It is proposed that a unique mechanism is evoked by all substances tested that influence lymph flow; this mechanism involves electrolytes, and more specifically, the sodium ion. The findings reported here are in support of Crane's theory of Na+-dependent transport of water by the small intestine.

Quantitative studies of hemagglutination. Use of an electronic particle counter to investigate factors influencing cell aggregation.

Summary. A series of factors influencing antibody‐mediated red cell agglutination has been investigated quantitatively, employing an electronic cell counting technic. Increasing duration of red cell storage was shown to decrease mean red cell number per agglutinate more significantly than it did total percentage agglutination. The expected enhancement by lowered temperatures of agglutination in a saline‐agglutinating system was demonstrated. Hydrogen ion concentration had little effect on agglutination in the pH ranges 6.2 to 8.3 in either a saline agglutinating system or one employing antiglobulin serum. Hypotonic suspending media resulted in enhanced agglutination in both types of systems. In a saline agglutinating system increased phosphate concentrations enhanced agglutination, while isotonic solutions of NaCl, KCl or MgCl2 yielded results comparable to those obtained employing triethanolamine‐buffered saline. Increased agglutination in both systems was produced by increasing the duration or speed of centrifugation, while more violent agitation during the disaggregation phase of the experiments yielded less fully agglutinated systems after equilibrium was attained.