scholarly journals Effect of sodium and potassium ions on the electrical activity of single cells in the lateral eye of the horseshoe crab

1962 ◽  
Vol 161 (2) ◽  
pp. 319-343 ◽  
Author(s):  
R. Kikuchi ◽  
K. Naito ◽  
I. Tanaka
Keyword(s):  
Electrical Activity ◽  
Horseshoe Crab ◽  
Single Cells ◽  
Potassium Ions ◽  
Lateral Eye ◽  
Sodium And Potassium

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.

Tetanic hyperpolarization of single medullated nerve fibers in sodium and lithium

1976 ◽  
Vol 231 (4) ◽  
pp. 1033-1038 ◽  
Author(s):  
GM Schoepfle
Keyword(s):  
Steady State ◽  
Interspike Interval ◽  
Nerve Fibers ◽  
Repetitive Stimulation ◽  
Time Dependent ◽  
Potassium Ions ◽  
Current Densities ◽  
Medullated Nerve Fiber ◽  
Sodium And Potassium ◽  
Stimulation Of

Repetitive stimulation of a single medullated nerve fiber of Xenopus yields a succession of postspike voltage-time curves which are nearly coincident until attainment of a voltage that corresponds to that of the maximum attained by the normal postspike undershoot. Initially the interspike potential returns toward a resting level after this brief phase of hyperpolarization. However, as tetanization proceeds, a pattern of hyperpolarization develops with the result that, in the tetanic steady state, there exists a progressive hyperpolarization throughout each interspike interval. Extent of postspike hyperpolarization in terms of a deviation deltaVm from the resting level of membrane potential is approximated by the variation deltaVm = delta[MNa + MK]/[GNa + GK] where MNa and MK are current densities associated with active pumping of sodium and potassium ions and GNa and GK are corresponding time-dependent leak conductances. Tetanic hyperpolarization is reversibly abolished by cyanide and by exposure to lithium Ringer. Eventual reappearance of tetanic hyperpolarization in the presence of lithium Ringer suggests lithium pumping.

scholarly journals Effect of Handling on ATP Utilization of Cerebral Na,K-ATPase in rats with Trimethyltin-Induced Neurodegeneration.

2021 ◽  
Author(s):  
Barbora Kalocayova ◽  
Denisa Snurikova ◽  
Jana Vlkovicova ◽  
Veronika Navarova Stara ◽  
Dominika Michalikova ◽  
...  
Keyword(s):  
Cerebral Cortex ◽  
Kinetic Properties ◽  
Potassium Ions ◽  
Catalytic Subunits ◽  
Key Enzyme ◽  
Male Wistar Rats ◽  
Frontal Cerebral Cortex ◽  
Α3 Subunit ◽  
The Brain ◽  
Sodium And Potassium

Abstract Previously it was shown that for reduction of anxiety and stress of experimental animals, preventive handling seems to be one of the most effective methods. The present study was oriented on Na,K-ATPase, a key enzyme for maintaining proper concentrations of intracellular sodium and potassium ions. Malfunction of this enzyme has an essential role in the development of neurodegenerative diseases. It is known that this enzyme requires approximately 50% of the energy available to the brain. Therefore in the present study utilization of the energy source ATP by Na,K-ATPase in the frontal cerebral cortex, using the method of enzyme kinetics was investigated. As a model of neurodegeneration treatment with Trimethyltin (TMT) was applied. Daily handling (10 min/day) of healthy rats and rats suffering neurodegeneration induced by administration of TMT in a dose of (7.5 mg/kg), at postnatal days 60-102 altered the expression of catalytic subunits of Na,K-ATPase as well as kinetic properties of this enzyme in frontal cerebral cortex of adult male Wistar rats. Everyday handling of rats, beside the previously published beneficial effect on spatial memory was accompanied by improwed maintenance of sodium homeeostasis in frontal cortex of brains. The key system responsible for this proces, the Na,K-ATPase was able to utilize better the energy substrate ATP. In rats with TMT-induced neurodegeneration handling promoted the expresion of α2 isoform of the enzyme which is typical for glial cells. In healthy rats the handling was followed by increased expression α3 subunit which is typical for neurons.

Chemical Properties of Zwitterionic Imidazolium Alkanecarboxylates Studied in Gas-Phase by Electrospray Ionization – Collision-Induced Dissociation / Cviterjonu Tipa Imidazolija Alkānkarboksilātu Ķīmiskās Īpašības Gāzes Fāzē, Kas Pētītas Ar Elektroizsmidzināšanas Jonizāciju – Sadursmju Inducēto Disociāciju

2012 ◽  
Vol 51 (3) ◽  
pp. 249-256
Author(s):  
A. Podjava ◽  
P. Mekss ◽  
A. Zicmanis ◽  
S. Krasnov
Keyword(s):  
Gas Phase ◽  
Chemical Properties ◽  
Collision Induced Dissociation ◽  
Potassium Ions ◽  
Hydrogen Deuterium Exchange ◽  
Carboxylate Group ◽  
Hydrogen Deuterium ◽  
Ionization Mode ◽  
Sodium And Potassium ◽  
Phase Chemical

Gas-phase chemical properties of several (1-methylimidazol-3-io)-alkane-1-carboxylates (alkane=ethane, propane and butane) have been investigated in this study. These substances are synthesized using classical transformations and analyzed in positive ionization mode using collision-induced dissociation (0-50 eV). These experiments were carried out in both deuterated and undeuterated solvent media. The data obtained in this study show, that carboxylate group weakly influences fragmentation of zwitterionic imidazolium carboxylates in positive electrospray mode. On the other hand, these compounds exert a tendency to form various adducts with sodium and potassium ions and to participate in hydrogen/deuterium exchange in the gas phase.

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