The Excretion of Sodium, Potassium and Water by the Malpighian Tubules of the Stick inSect, Dixippus Morosus (Orthoptera, Phasmidae)

1955 ◽  
Vol 32 (1) ◽  
pp. 200-216 ◽  
Author(s):  
J. A. RAMSAY
Keyword(s):  
Potassium Concentration ◽  
Physiological Activity ◽  
Liquid Paraffin ◽  
Stick Insect ◽  
Proximal Region ◽  
Malpighian Tubules ◽  
Electrochemical Gradient ◽  
Sodium Potassium ◽  
Single Tubules ◽  
Sodium And Potassium

1. The excretion of sodium, potassium and water by the Malpighian tubules of the stick insect has been further studied in preparations of single tubules isolated in droplets of medium under liquid paraffin. 2. There is some gradation of physiological activity along the length of the superior tubule. Sodium, potassium and water are secreted into the tubule at all levels, but the sodium/potassium ratio is greater in the proximal region. 3. The proximal and middle regions of the inferior tubule have not been shown to differ in any way from the corresponding regions of the superior tubule. The distal dilatation has quite different properties and does not produce urine. 4. The rate of urine flow increases markedly as the potassium concentration in the medium is increased; the corresponding effect of sodium is barely detectable. 5. Sodium, like potassium, can be actively transported against an electrochemical gradient, and does not appear to compete with potassium in the secretory mechanism. 6. The rates of secretion of sodium and potassium vary in direct proportion to the respective concentrations of these ions in the medium. The rate of secretion of potassium is more than ten times greater than that of sodium.

scholarly journals Excretion by the Malpighian Tubules of the Stick Insect, Dixippus Morosus (Orthoptera, Phasmidae): Calcium, Magnesium, Chloride, Phosphate and Hydrogen Ions

1956 ◽  
Vol 33 (4) ◽  
pp. 697-708
Author(s):  
J. A. RAMSAY
Keyword(s):  
General Problem ◽  
Magnesium Chloride ◽  
Liquid Paraffin ◽  
Stick Insect ◽  
Urine Flow ◽  
Malpighian Tubules ◽  
Hydrogen Ions ◽  
Calcium Magnesium

1. The excretion of calcium, magnesium, chloride, phosphate and hydrogen ions has been studied in preparations of single Malpighian tubules isolated in drops of serum under liquid paraffin. 2. The concentrations of calcium, magnesium and chloride are always lower in the urine than in the serum. 3. The concentration of phosphate is always greater in the urine than in the serum. As the concentration of phosphate in the serum increases, the rate of urine flow also increases. 4. The urine is always alkaline to the serum but becomes acid in the rectum. 5. The general problem of excretion by Malpighian tubules is briefly reviewed and discussed.

THE EFFECTS OF OESTROGEN AND PROGESTERONE ON THE SODIUM AND POTASSIUM CONCENTRATIONS OF RAT UTERINE FLUID

1970 ◽  
Vol 47 (3) ◽  
pp. 309-319 ◽  
Author(s):  
C. A. B. CLEMETSON ◽  
V. R. MALLIKARJUNESWARA ◽  
M. M. MOSHFEGHI ◽  
J. J. CARR ◽  
J. H. WILDS
Keyword(s):  
Membrane Potential ◽  
Potassium Concentration ◽  
Ovarian Hormones ◽  
Pronounced Change ◽  
Sodium Potassium ◽  
Delayed Implantation ◽  
Uterine Fluid ◽  
Sodium And Potassium

SUMMARY Studies of the electrolyte concentrations of uterine fluid samples from spayed rats, after injection of ovarian hormones, showed a much higher potassium concentration after treatment with oestrogen (42·3 m-equiv./1.) than with progesterone (20·8 m-equiv./1.). There was an even more pronounced change in the sodium: potassium ratio, which fell from 7·3 to 1 with progesterone to 2·5 to 1 with oestrogen. These findings are supported by recalculation of the results of Heap & Lamming (1962). It is suggested that these changes in the Na+ and K+ concentrations of uterine fluid produce changes in the membrane potential of the endometrium which could account for delayed implantation of the negatively charged blastocyst under progesterone dominance and implantation under oestrogen dominance.

The Composition of Haemolymth in Aquatic Insects

1962 ◽  
Vol 39 (3) ◽  
pp. 325-344 ◽  
Author(s):  
D. W. SUTCLIFFE
Keyword(s):  
Amino Acids ◽  
Aquatic Insects ◽  
Free Amino Acids ◽  
Free Amino ◽  
Inorganic Phosphate ◽  
Potassium Concentration ◽  
Chloride Concentration ◽  
Sodium Concentration ◽  
Sodium Potassium ◽  
Sodium And Potassium

1. Analyses were made of haemolymph obtained from aquatic representatives of nine major orders in the Insecta. 2. In the Odonata, Plecoptera, Ephemeroptera and Hemiptera-Heteroptera, the sodium concentration is relatively high and the potassium concentration is low. The chloride concentration is relatively high, but it never exceeds the sodium concentration. 3. In the Neuroptera, Coleoptera, Trichoptera and Diptera the sodium concentration is relatively high and the potassium concentration is low. In Nymphula nymphaeta (Lepidoptera) both the sodium and potassium concentrations are low. In all of these endopterygotes the chloride concentration is relatively low. 4. There is no correlation between diet and the sodium/potassium ratio in haemolymph of aquatic insects. 5. The problem of cation-anion balance is discussed. It is suggested that free amino acids contribute little to the anion pool. Bicarbonate and phosphate, largely as inorganic phosphate, contribute a small amount to the anion pool in exopterygotes. Phosphate contributes considerably more to the anion pool in some endopterygotes. Nevertheless, in all of the insects investigated, there is a deficit of anions. This deficit is usually greater in the endopterygotes. 6. The calculated osmotic activities of the known ions and free amino acids are less than the observed osmotic activities of haemolymph. It is inferred that non-amino organic acids must be present. Preliminary investigations indicate that non-amino acids are present in the concentrations required to account for both the osmotic and the anion deficits.

Active Transport of Water by the Malpighian Tubules of the Stick Insect, Dixippus Morosus (Orthoptera, Phasmidae)

1954 ◽  
Vol 31 (1) ◽  
pp. 104-113 ◽  
Author(s):  
J. A. RAMSAY
Keyword(s):  
Osmotic Pressure ◽  
Active Transport ◽  
Liquid Paraffin ◽  
Stick Insect ◽  
Malpighian Tubules ◽  
Normal Rate ◽  
Urine Production

1. Single Malpighian tubules of the stick insect have been studied as preparations isolated in drops of haemolymph under liquid paraffin. Measurements of osmotic pressure have been made on haemolymph and urine. 2. The urine is more or less isotonic with the haemolymph over a wide (45-145%) range of osmotic pressure. But in a majority of cases the urine is slightly but significantly hypotonic to the haemolymph. 3. From these and other observations it is concluded that water must be actively transported across the wall of the tubule. The implications of this conclusion are discussed. 4. The normal rate of urine production is of the order of 0.07 x 1o-3 cu.mm./sq.mm./min. The rate increases with increasing dilution of the haemolymph and vice versa. 5. Urine production normally ceases, probably as a result of distension of the tubule, when the pressure in the lumen rises to about 20 cm. H2O.

Urine Formation by the Malpighian Tubules of Calliphora

1968 ◽  
Vol 48 (1) ◽  
pp. 159-174
Author(s):  
M. J. BERRIDGE
Keyword(s):  
Osmotic Pressure ◽  
Potassium Concentration ◽  
Malpighian Tubules ◽  
Apical Surface ◽  
Bathing Medium ◽  
Sodium Potassium ◽  
Basal Plasma ◽  
External Potassium ◽  
Potassium Secretion ◽  
Urine Formation

1. Rate of urine formation is very sensitive to potassium concentration. 2. Potassium is concentrated in the urine by a mechanism which is independent of other monovalent cations. Rubidium, caesium and sodium are also capable of maintaining a flow of urine. At low external potassium concentrations, sodium stimulates potassium secretion. 3. Rate of urine secretion is stimulated by low osmotic pressures; the osmotic pressure of urine was slightly hypertonic throughout the range of external osmotic pressure employed. Addition of sucrose depresses rate of urine secretion; the potassium concentration of the urine increased by 1 mM/l. for each 2 mM/l. of sucrose added to the bathing medium. 4. Urine formation is insensitive to sulphanilamide, acetazolamide, ouabain and a wide variation of pH. 5. These observations are discussed in relation to the hypothesis that potassium secretion takes place across both surfaces of the cell. The pump on the basal surface may be a coupled sodium-potassium pump, whereas that on the apical surface may be electrogenic. 6. Microvilli at the apical surface or channels formed by a complex infolding of the basal plasma membrane may represent structural devices by which standing osmotic gradients can be established during solute-linked water transport across the cells of Malpighian tubules.

scholarly journals Influence of Erythrocytes on Direct Potentiometric Determination of Sodium and Potassium

1983 ◽  
Vol 20 (2) ◽  
pp. 116-120 ◽  
Author(s):  
P Bijster ◽  
H L Vader ◽  
C L J Vink
Keyword(s):  
Whole Blood ◽  
Potassium Concentration ◽  
Reference Electrode ◽  
Sodium Concentration ◽  
General Phenomenon ◽  
Liquid Junction ◽  
Direct Potentiometry ◽  
The Difference ◽  
Sodium And Potassium

We have shown that the sodium concentration in whole blood measured by direct potentiometry is higher than in plasma. The ‘erythrocyte-effect’, already described by Siggaard Andersen, is most pronounced for instruments equipped with a reference electrode with an open static liquid junction and is thus a general phenomenon. Instruments with a modified liquid junction show less interference. The same phenomenon appears for the determination of the potassium concentration, although the difference between whole blood and plasma, when measured with instruments equipped with a modified liquid junction, can be neglected in practice.

scholarly journals Changes in the Membrane Permeability of Frog's Sartorius Muscle Fibers in Ca-Free EDTA Solution

1963 ◽  
Vol 47 (2) ◽  
pp. 379-392 ◽  
Author(s):  
H. Kimizuka ◽  
K. Koketsu
Keyword(s):  
Membrane Permeability ◽  
Chloride Content ◽  
Chloride Ions ◽  
Sartorius Muscle ◽  
Constant Field ◽  
Sodium Influx ◽  
Sodium Potassium ◽  
Edta Solution ◽  
Frog Sartorius ◽  
Sodium And Potassium

The changes in the membrane permeability to sodium, potassium, and chloride ions as well as the changes in the intracellular concentration of these ions were studied on frog sartorius muscles in Ca-free EDTA solution. It was found that the rate constants for potassium and chloride efflux became almost constant within 10 minutes in the absence of external calcium ions, that for potassium increasing to 1.5 to 2 times normal and that for chloride decreasing about one-half. The sodium influx in Ca-free EDTA solution, between 30 and 40 minutes, was about 4 times that in Ringer's solution. The intracellular sodium and potassium contents did not change appreciably but the intracellular chloride content had increased to about 4 times normal after 40 minutes. By applying the constant field theory to these results, it was concluded that (a) PCl did not change appreciably whereas PK decreased to a level that, in the interval between 10 and 40 minutes, was about one-half normal, (b) PNa increased until between 30 and 40 minutes it was about 8 times normal. The low value of the membrane potential between 30 and 40 minutes was explained in terms of the changes in the membrane permeability and the intracellular ion concentrations. The mechanism for membrane depolarization in this solution was briefly discussed.

Cardiovascular and renal effects of hypoxia in conscious carotid body-denervated rats

1993 ◽  
Vol 74 (6) ◽  
pp. 2795-2800 ◽  
Author(s):  
R. Behm ◽  
H. Mewes ◽  
W. H. DeMuinck Keizer ◽  
T. Unger ◽  
R. Rettig
Keyword(s):  
Carotid Body ◽  
Normobaric Hypoxia ◽  
Sodium Potassium ◽  
Water Excretion ◽  
Excretory Function ◽  
Arterial Blood ◽  
Peripheral Arterial ◽  
Renal Responses ◽  
Arterial Po2 ◽  
Sodium And Potassium

The contribution of peripheral arterial chemoreceptors to cardiovascular and renal responses to acute hypocapnic hypoxia is currently not well understood. We compared the effects of normobaric hypoxia on mean arterial blood pressure (MABP), heart rate, glomerular filtration rate (GFR), renal blood flow (RBF), and renal volume and electrolyte excretion in conscious unilaterally nephrectomized carotid body-denervated (n = 10) and sham-operated (n = 10) control rats. Thirty minutes of normobaric hypoxia (12.5% O2) resulted in significant reductions in arterial PO2 and PCO2 as well as decreases in MABP, GFR, RBF, and renal sodium, potassium, and water excretion. These effects occurred more rapidly and/or were significantly more pronounced in carotid body-denervated than in sham-operated rats. These data indicate that moderate acute hypocapnic hypoxia has profound effects on systemic and renal hemodynamics as well as on renal excretory function in conscious rats. We conclude that stimulation of the peripheral arterial chemoreceptors can partially offset the hypoxia-induced decreases in MABP, RBF, GFR, urine flow, and urinary sodium and potassium excretion, thereby helping to maintain cardiovascular as well as fluid and electrolyte homeostasis.

Effects of Synthetic Atrial Natriuretic Peptides on Sodium-Potassium Transport in Human Erythrocytes

1985 ◽  
Vol 69 (2) ◽  
pp. 223-226 ◽  
Author(s):  
G. A. Sagnella ◽  
D. A. Nolan ◽  
A. C. Shore ◽  
G. A. MacGregor
Keyword(s):  
Loop Diuretic ◽  
Sodium Pump ◽  
Human Erythrocytes ◽  
Atrial Natriuretic Peptides ◽  
Sodium Potassium ◽  
Potassium Ion Transport ◽  
Wide Range ◽  
Natriuretic Effect ◽  
Cotransport System ◽  
Sodium And Potassium

1. The effects of synthetic human and rat atrial peptides on sodium and potassium ion transport has been investigated in intact human erythrocytes. 2. The effects of these peptides have been tested on the active, sodium pump-dependent (ouabain-sensitive) and on the sodium-potassium cotransport system (bumetanide-sensitive) with 86Rb used as a tracer. 3. Human (α-ANP, 28 amino acids) or rat (atriopeptin III) atrial peptides, over a wide range of concentrations, did not influence the uptake of 86Rb in either the ouabain-sensitive or the bumetanide-sensitive transport system. 4. These results suggest that the natriuretic effect of the atrial peptides is not mediated through inhibition of the sodium pump or the loop-diuretic-sensitive Na-K cotransport.

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