scholarly journals Exchanges of Sodium Ions in the Central Nervous System of Anodonta Cygnea

1969 ◽  
Vol 51 (2) ◽  
pp. 287-296
Author(s):  
DE FOREST MELLON ◽  
J. E. TREHERNE
Keyword(s):  
Extracellular Fluid ◽  
Freshwater Mussel ◽  
Potassium Ions ◽  
Sodium Ions ◽  
Anodonta Cygnea ◽  
Rapid Exchange ◽  
Exponential Decline ◽  
The Central Nervous System ◽  
Stage Process ◽  
Sodium And Potassium

1. The concentrations of sodium and potassium ions have been measured in the blood and tissues of the cerebro-visceral connective of the freshwater mussel Anodonta. It is shown that, despite the relatively low concentration of sodium ions in the blood, a concentration gradient of this cation is maintained between the extracellular fluid and the nerve cells because of the extremely low intracellular concentration of this cation. 2. Experiments using 24Na and 22Na have shown that there is relatively rapid exchange of sodium ions between the blood and the central nervous tissues. 3. The efflux of labelled sodium occurred as a two-stage process, in which an initial fast fraction gives way to a slower exponential decline. The results can be accounted for on the assumption that efllux of sodium ions in the fast fraction, at 0° C., represents the cations contained in the extracellular fluid. This assumption implies that there is little regulation of the over-all concentration of sodium ions in the extracellular fluid. 4. The results are discussed in relation to the available evidence on the structure and electrophysiology of the cerebro-visceral connectives.

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.

Accessibility of the Central Nervous Connectives of Anodonta Cygnea to a Compound of Large Molecular Weight

1972 ◽  
Vol 56 (2) ◽  
pp. 493-499
Author(s):  
N. J. LANE ◽  
J. E. TREHERNE
Keyword(s):  
Cell Layer ◽  
Extracellular Fluid ◽  
Water Soluble ◽  
Bathing Medium ◽  
Anodonta Cygnea ◽  
Rapid Exchange ◽  
Soluble Ions ◽  
Large Molecular Weight ◽  
Water Soluble Ions ◽  
Intercellular Clefts

1. Ultrastructural observations on the uptake of an exogenous tracer substance, horseradish peroxidase (M.W. 40,000), have shown that this large molecule can penetrate the neural lamella in intact cerebro-visceral connectives of the lamellibranch, Anodonta cygnea. 2. Peroxidase molecules were also observed to penetrate between the intercellular clefts formed by adjacent membranes of the underlying peripheral glial cell layer and to move extensively into the underlying extracellular spaces. 3. These observations confirm the results of previous electrophysiological, radioisotopic and ultrastructural investigations indicating that a relatively rapid exchange of water-soluble ions and molecules occurs between the blood, or bathing medium, and the extracellular fluid bathing the axon surfaces in intact connectives.

Potassium and Water Distribution in Depression

1966 ◽  
Vol 112 (484) ◽  
pp. 269-276 ◽  
Author(s):  
David Murray Shaw ◽  
Alec Coppen
Keyword(s):  
Action Potentials ◽  
Water Distribution ◽  
Extracellular Fluid ◽  
Severe Depression ◽  
The Body ◽  
Extracellular Water ◽  
Excitable Cells ◽  
Cell Excitability ◽  
The Central Nervous System ◽  
Sodium And Potassium

The ionic theory of cell excitability shows how impulses are generated, conducted and propagated by movements of ions between the cells and the extracellular fluid. It is known that changes in the concentration of sodium and potassium in either the extracellular water (E.C.W.) or the intracellular water (I.C.W.) may have a marked effect on the resting and action potentials of excitable cells. If affective disorders are manifestations of complex but reversible changes in brain excitability, hen these in turn might be caused by alterations in the concentration of electrolytes within the cells of the central nervous system (C.N.S.). Although it is not possible to measure the distribution of electrolytes specifically in the C.N.S. in man, it is possible to measure their distribution in the body as a whole. In previous papers we have shown that residual sodium (intracellular plus a small quantity of bone sodium) is increased by 50 per cent. in depression (Coppen and Shaw, 1963) and by nearly 200 per cent. in mania (Coppen, Shaw, Malleson and Costain, 1965). The present paper shows that there are also abnormalities in the distribution of potassium, the other main cation determining cell excitability, in patients suffering from severe depression.

scholarly journals The Kinetics of Sodium Extrusion in Striated Muscle As Functions of the External Sodium and Potassium Ion Concentrations

1971 ◽  
Vol 57 (2) ◽  
pp. 164-187 ◽  
Author(s):  
R. A. Sjodin
Keyword(s):  
Sodium Ion ◽  
Ion Concentration ◽  
Potassium Ions ◽  
Sodium Ions ◽  
Sodium Efflux ◽  
Sodium Dependent ◽  
Na Efflux ◽  
External Potassium ◽  
Sodium Extrusion ◽  
Sodium And Potassium

After a 20 min initial washout, the rate of loss of radioactively labeled sodium ions from sodium-enriched muscle cells is sensitive to the external sodium and potassium ion concentrations. In the absence of external potassium ions, the presence of external sodium ions increases the sodium efflux. In the presence of external potassium ions, the presence of external sodium ions decreases the sodium efflux. In the absence of external potassium ions about one-third of the Na+ efflux that depends upon the external sodium ion concentration can be abolished by 10-5 M glycoside. The glycoside-insensitive but external sodium-dependent Na+ efflux is uninfluenced by external potassium ions. In the absence of both external sodium and potassium ions the sodium efflux is relatively insensitive to the presence of 10-5 M glycoside. The maximal external sodium-dependent sodium efflux in the absence of external potassium ions is about 20% of the magnitude of the maximal potassium-dependent sodium efflux. The magnitude of the glycoside-sensitive sodium efflux in K-free Ringer solution is less than 10% of that observed when sodium efflux is maximally activated by potassium ions. The inhibition of the potassium-activated sodium efflux by external sodium ions is of the competitive type. Reducing the external sodium ion concentration displaces the plots of sodium extrusion rate vs. [K]o to the left and upwards.

scholarly journals Resolution of Pump and Leak Components of Sodium and Potassium Ion Transport in Human Erythrocytes

1967 ◽  
Vol 50 (5) ◽  
pp. 1201-1220 ◽  
Author(s):  
R. L. Post ◽  
C. D. Albright ◽  
K. Dayani
Keyword(s):  
Cardiac Glycoside ◽  
Potassium Ion ◽  
Sodium Ion ◽  
The Other ◽  
Potassium Ions ◽  
Sodium Ions ◽  
Passive Transport ◽  
Potassium Ion Transport ◽  
Pump Activity ◽  
Sodium And Potassium

Further support for the pump-leak concept was obtained. Net transport was resolved into pump and leak components with the cardiac glycoside, ouabain. The specificity of ouabain as a pump inhibitor was demonstrated by its ineffectiveness when the pump was already inhibited by lack of one of the three pump substrates, sodium ion, potassium ion, or adenosine triphosphate. In the presence of ouabain the rates of passive transport of sodium and potassium ions changed almost in proportion to changes in their extracellular concentrations when one ion was exchanged for the other. In the presence of ouabain and at the extracellular concentrations which produced zero net transport, the ratio of potassium ions to sodium ions was 1.2-fold higher inside the cells than outside. This finding was attributed to a residual pump activity of less than 2% of capacity. The permeability to potassium ions was 10% greater than the permeability to sodium ions. A test was made of the independence of pump and leak. Conditions were chosen to change the rate through each pathway separately or in combination. When both pathways were active, net transport was the sum of the rates observed when each acted separately. A ratio of three sodium ions pumped outward per two potassium ions pumped inward was confirmed.

Axonal Function and Ionic Regulation in the Central Nervous System of a Phytophagous Insect (Carausius Morosus)

1967 ◽  
Vol 47 (2) ◽  
pp. 235-247
Author(s):  
J. E. TREHERNE ◽  
S. H. P. MADDRELL
Keyword(s):  
Ionic Composition ◽  
Extracellular Fluid ◽  
Extracellular Recording ◽  
Inorganic Ions ◽  
Sodium Ions ◽  
Phytophagous Insect ◽  
High Concentration ◽  
Action Current ◽  
Local Regulation ◽  
The Central Nervous System

1. Experiments vising intracellular and extracellular recording techniques indicate that, despite the specialized ionic composition of the haemolymph, the axons in the nerve cord of Carausius are conventional in that the action current is largely carried by sodium ions. 2. This effect is achieved by an appreciable regulation of the concentrations of inorganic ions in the extracellular fluid bathing the axon surfaces. 3. The extra-axonal regulation does not appear to result from any significant restriction in the accessibility of cations to the general extracellular system, but from a local regulation which appears to maintain a relatively high concentration of sodium ions at the axon surfaces. 4. It is suggested that such a regulation may be achieved by an extrusion of sodium ions from the glial cells into the restricted extra-axonal spaces demonstrated in the electron micrographs of this preparation.

A novel crowned porphyrin derived from meso-tetrakis(penta-fluorophenyl)porphyrin

2003 ◽  
Vol 07 (06) ◽  
pp. 399-404 ◽  
Author(s):  
Maria Carolina A. F. Gotardo ◽  
Hérica C. Sacco ◽  
Juvenal C. S. Filho ◽  
Antônio G. Ferreira ◽  
Antônio Claudio Tedesco ◽  
...  
Keyword(s):  
Crown Ether ◽  
Ionic Radius ◽  
Potassium Ions ◽  
Aggregation Process ◽  
Sodium Ions ◽  
Dimerization Constant ◽  
Chloroform Methanol ◽  
Sodium And Potassium ◽  
Spectroscopic Behavior ◽  
Absorption Measurements

The porphyrin 5,10,15,20-tetrakis[4-(1,4,7,10,13-pentaoxacyclopentadecane-2-aminomethyl)2,3,5,6-tetrafluorophenyl]porphyrin,T15C5P, was synthesized by the reaction of 5,10,15,20-tetrakis(pentafluorophenyl)porphyrin with the crown ether 2-aminomethyl-(15-crown-5). The crowned porphyrin showed a distinct spectroscopic behavior in the presence of sodium and potassium ions. Dimerization studies based on absorption measurements clearly indicate that T15C5P aggregates in the presence of potassium ions in chloroform/methanol medium (1.0 × 10−5 mol.L −1 or 1.0 × 10−4 mol.L −1), with a dimerization constant ( K D ) of 2.14 × 10−5 and 2.23 × 10−5, respectively. The same formalism applied to the T15C5P in the presence of sodium ions indicated absence of the aggregation process. The ionic radius of Na + is suitable to fit well into the cavity of 15-crown-5 moieties, leading to intramolecular complexes only. Potassium ion is too large to lie in the hole of the crown ether entities and is probably located between two porphyrin molecules, promoting 2:1 aggregated complexes through it's sandwiching, as is observed for phthalocyanines.

The Movements of Sodium Ions in the Isolated Abdominal Nerve Cord of the Cockroach, Periplaneta Americana

1961 ◽  
Vol 38 (3) ◽  
pp. 629-636
Author(s):  
J. E. TREHERNE
Keyword(s):  
Nerve Cord ◽  
Periplaneta Americana ◽  
Potassium Cyanide ◽  
Ringer Solution ◽  
Potassium Ions ◽  
Sodium Ions ◽  
Sodium Efflux ◽  
Exponential Decline ◽  
External Potassium ◽  
Nerve Cords

1. The rate of loss of sodium ions from the abdominal nerve cord of Periplaneta has been determined by following the decline in radioactivity of 24Na-loaded nerve cords isolated in flowing Ringer solution. 2. In all of the experiments there was an initial rapid exponential decline in radioactivity which eventually gave way to a second slower phase. 3. The initial exponential extrusion of sodium ions was appreciably reduced by the presence of potassium cyanide and 2:4-dinitrophenol. 4. The rate of sodium efflux was not reduced in sodium-free solutions, but was decreased in the absence of external potassium ions. 5. It is concluded that sodium ions are extruded from the nerve cord by a metabolically maintained secretory mechanism which is also associated with the uptake of potassium ions.

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