On the Concept of Resting Potential—Pumping Ratio of the Na+/K+ Pump and Concentration Ratios of Potassium Ions Outside and Inside the Cell to Sodium Ions Inside and Outside the Cell

2012 ◽  
Vol 246 (1) ◽  
pp. 75-90 ◽  
Author(s):  
Ning Xu
Keyword(s):  
Resting Potential ◽  
Potassium Ions ◽  
Sodium Ions ◽  
Concentration Ratios

Sodium and Potassium Fluxes in the Abdominal Nerve Cord of the Cockroach, Periplaneta Americana L

1961 ◽  
Vol 38 (2) ◽  
pp. 315-322
Author(s):  
J. E. TREHERNE
Keyword(s):  
Central Nervous System ◽  
Nervous System ◽  
Nerve Cord ◽  
Periplaneta Americana ◽  
Unit Area ◽  
Potassium Ions ◽  
Sodium Ions ◽  
Nerve Sheath ◽  
The Central Nervous System ◽  
Sodium And Potassium

1. The influx of sodium and potassium ions into the central nervous system of Periplaneta americana has been studied by measuring the increase in radioactivity within the abdominal nerve cord following the injection of 24NA and 42K. into the haemolymph. 2. The calculated influx of sodium ions was approximately 320 mM./l. of nerve cord water/hr. and of potassium ions was 312 mM./l. of nerve cord water/hr. These values are very approximately equivalent to an influx per unit area of nerve cord surface of 13.9 x 10-2 M cm. -2 sec.-1 for sodium and 13.5 x 10-12 M cm. -2 sec.-1 for potassium ions. 3. The relatively rapid influxes of these ions are discussed in relation to the postulated function of the nerve sheath as a diffusion barrier. It is suggested that a dynamic steady state rather than a static impermeability must exist across the sheath surrounding the central nervous system in this insect.

scholarly journals Biochemical and Molecular Studies on the Role of Rosemary (Rosmarinus officinalis) Extract in Reducing Liver and Kidney Toxicity Due to Etoposide in Male Rats

2019 ◽  
pp. 1-11
Author(s):  
Majd Almakhatreh ◽  
Ezar Hafez ◽  
Ehab Tousson ◽  
Ahmed Masoud
Keyword(s):  
Dna Damage ◽  
Calcium Ions ◽  
Chloride Ions ◽  
Male Rats ◽  
Control Group ◽  
Potassium Ions ◽  
Sodium Ions ◽  
Total Proteins ◽  
Kidney Toxicity ◽  
Liver And Kidney

Aims: Etoposide (Vepesid) is chemotherapeutic drugs that inhibit topoisomerase II activity and long been used for treatment of human malignancies, where it is a semi-synthetic compound derived from the plant Podophyllum peltatum. The current study was designed to investigate the possible protective effect of rosemary extract against Etoposide -induced changes in liver and kidney functions, and DNA damage in rats. Materials and Methods: A total of 50 male Wistar albino rats were divided randomly into four groups (1st group was control; 2nd group was treated with rosemary, 3rd group was received etoposide, and 4th & 5th groups was co- and post treated groups respectively). Results: The administration of Etoposide revealed a significant increase in serum ALT, AST, ALP, creatinine, urea, potassium ions, chloride ions, and DNA damage. In contrast; a significant decrease in albumen, total proteins, sodium ions, and calcium ions were when compared with control group. This increased in ALT, AST, ALP, creatinine, urea, potassium ions, chloride ions, and DNA damage was reduced after administration of rosemary when co-treated with etoposide (G4), or post-treated after etoposide  (G5) for four weeks with lowest damage in G4. Also, this decreased in albumen, total proteins, sodium ions, and calcium ions was increased after administration of rosemary when co-treated with etoposide (G4), or post-treated after etoposide (G5) for four weeks with lowest damage in G4. Conclusion: It could be concluded that rosemary has a promising role and it worth to be considered as a natural substance for protective the liver and kidney toxicity induced by etoposide (Vepesid) chemotherapy.

An Investigation of the Electrogenic Sodium Pump in Snail Neurones, Using the Constant-Field Theory

1969 ◽  
Vol 51 (1) ◽  
pp. 181-201
Author(s):  
R. B. MORETON
Keyword(s):  
Field Equation ◽  
Sodium Pump ◽  
Membrane Resistance ◽  
Resting Potential ◽  
Constant Field ◽  
Sodium Ions ◽  
Intracellular Potassium ◽  
Electrogenic Sodium Pump ◽  
Snail Neurones ◽  
Intracellular Potassium Concentration

1. Sodium ions injected into giant neurones of Helix aspersa by diffusion from low-resistance microelectrodes caused hyperpolarization of the cells. Under these conditions the behaviour of the resting potential could be described by a modified ‘constant-field’ equation, including a term representing the effect of a potassiumsensitive, electrogenic sodium pump. 2. Exposure to potassium-free solution, ouabain or cyanide abolished the hyperpolarization, and caused a gradual fall in the intracellular potassium concentration, as estimated from the constant-field equation. 3. Assuming that this fall was due to replacement of intracellular potassium by injected sodium ions, it was possible to calculate the rates of injection and pumping of sodium ions, and, using the measured membrane resistance of the cell, the hyperpolarization which the sodium pump could cause, if it were electrogenic. 4. This was related to the observed hyperpolarization, supporting the view that the latter was caused by stimulation of the electrogenic sodium pump.

Relationship of depolarization to phosphorus metabolism and transport in excitable tissues

1964 ◽  
Vol 207 (6) ◽  
pp. 1435-1440 ◽  
Author(s):  
L. G. Abood ◽  
I. Koyama ◽  
Virginia Thomas
Keyword(s):  
Ganglion Cells ◽  
Ringer Solution ◽  
Resting Potential ◽  
Spinal Ganglia ◽  
Potassium Ions ◽  
Transport Mechanisms ◽  
High Concentration ◽  
High K ◽  
Spinal Ganglion Cells ◽  
Relationship Of

In the presence of Ringer solution containing a high concentration of potassium ions, the incorporation of orthophosphate-P32 into ATP and other organophosphates of the desheathed sciatic nerve or spinal ganglia of bullfrog was inhibited over 75%. The inhibition in calcium-free Ringer solution containing EDTA was somewhat less. With increasing external K+ there was a good correlation between the decrease in the resting potential of spinal ganglion cells and the inhibition of P32 incorporation into ATP and phosphocreatine. Since oxidative phosphorylation or carbohydrate metabolism was not inhibited by high K+, it was concluded that the K+ interfered with the transport mechanisms involved in orthophosphate-P32 exchange across the nerve membrane. Pi transport was believed to involve the following three chain-linked reactions: 1) carrier + P ⇌ carrier P; 2) carrier P ⇌ carrier + Pi; 3) Pi + ADP ⇌ ATP, where the first two reactions occurred in the membrane and the third within mitochondria. Reaction I or II was presumed to be K+ sensitive. The possible mechanisms involved in such an inhibition are discussed in terms of present-day theories relating to bioelectric phenomena.

Intracellular distribution of cations and protein in regenerating rat liver

1963 ◽  
Vol 204 (2) ◽  
pp. 257-261 ◽  
Author(s):  
Edwin M. Uyeki
Keyword(s):  
Liver Regeneration ◽  
Temporal Pattern ◽  
Initial Phase ◽  
Intracellular Distribution ◽  
Potassium Ions ◽  
Sodium Ions ◽  
Protein Distribution ◽  
Intracellular Compartments ◽  
Two Phases ◽  
Early Phases

The intracellular distribution of several cell constituents was studied at different periods after partial hepatectomy in the rat. The temporal pattern of cation and protein distribution can be divided into two phases: there is an initial phase in the first 24 hr posthepatectomy in which sodium and water increased in tissues concomitant with a decrease in potassium and protein. The levels of these several constituents subsequently approached values that were higher than in the control at 1 and 2 days posthepatectomy and were generally maintained at these values throughout the assay period. The reasons for the accumulation of higher than normal levels of both potassium and sodium are as yet uninterpreted; the higher than control potassium-to-sodium ratios generally observed in the intracellular compartments are due to the relative greater accumulation of potassium ions over sodium ions during this period. Comparing the intracellular compartments, the greatest alterations of constituents in the early phases of liver regeneration were observed in the soluble portion.

scholarly journals Sexual maturity in rabbits defined by the physical and chemical characteristics of the semen

1978 ◽  
Vol 12 (1) ◽  
pp. 37-39 ◽  
Author(s):  
M. Macari ◽  
C. R. Machado
Keyword(s):  
New Zealand ◽  
Sexual Maturity ◽  
Chemical Characteristics ◽  
Potassium Ions ◽  
Sodium Ions ◽  
Mean Values ◽  
New Zealand White Rabbits ◽  
The Mean ◽  
Physical And Chemical ◽  
Artificial Vagina

Semen was collected weekly from New Zealand white rabbits from the 1st positive mounting test to 43 weeks of age by means of an artificial vagina. The mean values of the results obtained in the 1st and 20th collection weeks were respectively: volume (ml) 0·61 ± 0·30 and 0·70 ± 0·19; pH 7·22 ± 0·50 and 7·19 ± 0±15; concentration (sperm/mm3 x 103) 750 ± 207 and 381 ± 90; fructose (mg/l00 ml) 117 ± 58 and 203 ± 121; citric acid (mg/l00 ml) 256 ± 90 and 200 ± 97; sodium ions (mEq/l) 133 ± 31 and 163 ± 46; potassium ions (mEq/l) 40 ± 21 and 29 ± 14. On the basis of these results, New Zealand white rabbits reach sexual maturity by 6 months of age.

scholarly journals Flexibility of an Active Center in Sodium-Plus-Potassium Adenosine Triphosphatase

1969 ◽  
Vol 54 (1) ◽  
pp. 306-326 ◽  
Author(s):  
R. L. Post ◽  
S. Kume ◽  
T. Tobin ◽  
B. Orcutt ◽  
A. K. Sen
Keyword(s):  
Active Center ◽  
Adenosine Triphosphate ◽  
Adenosine Triphosphatase ◽  
Plasma Membranes ◽  
Adenosine Diphosphate ◽  
Ion Concentration ◽  
Potassium Ions ◽  
Sodium Ions ◽  
Intact Cells ◽  
Electrophoretic Patterns

In plasma membranes of intact cells an enzymatic pump actively transports sodium ions inward and potassium ions outward. In preparations of broken membranes it appears as an adenosine triphosphatase dependent on magnesium, sodium, and potassium ions together. In this adenosine triphosphatase a phosphorylated intermediate is formed from adenosine triphosphate in the presence of sodium ions and is hydrolyzed with the addition of potassium ions. The normal intermediate was not split by adenosine diphosphate. However, selective poisoning by N-ethylmaleimide or partial inhibition by a low magnesium ion concentration yielded an intermediate split by adenosine diphosphate and insensitive to potassium ions. Pulse experiments on the native enzyme supported further a hypothesis of a sequence of phosphorylated forms, the first being made reversibly from adenosine triphosphate in the presence of sodium ion and the second being made irreversiblyfrom the first and hydrolyzed in the presence of potassium ion. The cardioactive steriod inhibitor, ouabain, appeared to combine preferentially with the second form. Phosphorylation was at the same active site according to electrophoretic patterns of proteolytic phosphorylated fragments of both reactive forms. It is concluded that there is a conformational change in the active center for phosphorylation during the normal reaction sequence. This change may be linked to one required theoretically for active translocation of ions across the cell membrane.

scholarly journals ACTION OF POTASSIUM AND NARCOTICS ON RECTIFICATION IN NERVE AND MUSCLE

1944 ◽  
Vol 28 (1) ◽  
pp. 43-51 ◽  
Author(s):  
Rita Guttman
Keyword(s):  
Plasma Membrane ◽  
Sciatic Nerve ◽  
Rana Pipiens ◽  
Current Flow ◽  
Barium Chloride ◽  
Resting Potential ◽  
Sartorius Muscle ◽  
Potassium Ions ◽  
Excess Calcium ◽  
Simultaneous Decrease

Electrical rectification was demonstrated in whole sartorius muscle and sciatic nerve of Rana pipiens and also in the single giant nerve fiber of the northern squid, Ommastrephes illecibrossus. It is probably a property of the plasma membrane. Rectification decreases reversibly under the influence of increased concentrations of the potassium ion and with chloroform, veratrine sulfate and isoamyl carbamate. No effect was found with lack of calcium, excess calcium, or barium chloride. Decrease in rectification is invariably accompanied by simultaneous decrease in resting potential. A proposed explanation of the mechanism of rectification is discussed. Rectification in a living membrane, viz. a change in resistance with change in direction of current flow, may possibly be explained in terms of a change in the concentration of potassium ions in the membrane.

scholarly journals Aggregation dynamics of charged peptides in water: effect of salt concentration

2019 ◽  
Author(s):  
Susmita Ghosh ◽  
T Devanand ◽  
Upayan Baul ◽  
Satyavani Vemparala
Keyword(s):  
Early Stage ◽  
Potassium Ions ◽  
Sodium Ions ◽  
Magnesium Ions ◽  
Compact Structure ◽  
Biologically Relevant ◽  
Kinetics And Dynamics ◽  
Aggregate Morphology ◽  
Dynamics Simulations ◽  
Charged Peptides

Extensive molecular dynamics simulations have been employed to probe the effects of salts on the kinetics and dynamics of early-stage aggregated structures of steric zipper peptides in water. The simulations reveal that the chemical identity and valency of cation in the salt play a crucial roles in aggregate morphology of the peptides. Sodium ions induce the most aggregated structures but this is not replicated by potassium ions which are also monovalent. Divalent Magnesium ions induce aggregation, but to a lesser extent than that of sodium and their interactions with the charged peptides are also significantly different. The aggregate morphology in the presence of monovalent sodium ions is a compact structure with interpenetrating peptides, which differs from the more loosely connected peptides in the presence of either potassium or magnesium ions. The different ways in which the cations effectively renormalize the charges of peptides is suggested to be the cause of the differential effects of different salts studied here. These simulations underscore the importance of understanding both the valency and nature of of salts in biologically relevant aggregated structures.

scholarly journals INSECT MALPIGHIAN TUBULES: V-ATPase ACTION IN ION AND FLUID TRANSPORT.

1992 ◽  
Vol 172 (1) ◽  
pp. 417-429 ◽  
Author(s):  
SH Maddrell ◽  
MJ O'Donnell
Keyword(s):  
Ion Transport ◽  
Fluid Transport ◽  
Cation Transport ◽  
Malpighian Tubules ◽  
Luminal Cell ◽  
Potassium Ions ◽  
Sodium Ions ◽  
Cation Pump ◽  
Acid Fluid ◽  
Excretory Organs

Insect Malpighian tubules secrete fluid into the lumen as part of their function as excretory organs. The underlying ion transport is, when stimulated, faster than in any other known tissue. It is driven by the activity of an H+-transporting V-ATPase situated on the luminal cell membranes. This ATPase, together with cation/H+ antiporter(s), constitutes a common cation pump which can transport sodium ions, potassium ions or both. Treatments that selectively slow cation transport across the epithelium cause the secreted fluid to become alkaline, whereas those that selectively reduce the rate of anion passage lead to secretion of acid fluid.

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