Solvation of sodium ions studied by 23Na nuclear magnetic resonance

1968 ◽  
Vol 46 (22) ◽  
pp. 3425-3430 ◽  
Author(s):  
E. G. Bloor ◽  
R. G. Kidd
Keyword(s):  
Infinite Dilution ◽  
Sodium Iodide ◽  
Mixed Solvent ◽  
Chemical Shifts ◽  
Preferential Solvation ◽  
Anomalous Behavior ◽  
Sodium Ion ◽  
Sodium Ions ◽  
Nitrogen Donor ◽  
Solvent Systems

The 23Na chemical shifts, extrapolated to infinite dilution, of solutions containing sodium iodide dissolved in 14 different oxygen or nitrogen donor organic solvents have been determined. The observed range of chemical shifts can be successfully related to changes in the paramagnetic term of the general nuclear screening equation. A fair correlation between the magnitude of the paramagnetic term and the Lewis basicity of the solvent has been drawn. Those solvents showing anomalous behavior are the ones for which large magnetic anisotropies are to be expected. The 23Na chemical shifts for two mixed solvent systems containing sodium iodide have been obtained, and these support the conclusion that preferential solvation of the sodium ion occurs.

scholarly journals Free energy landscapes of sodium ions bound to DMPC–cholesterol membrane surfaces at infinite dilution

2016 ◽  
Vol 18 (13) ◽  
pp. 9036-9041 ◽  
Author(s):  
Jing Yang ◽  
Massimiliano Bonomi ◽  
Carles Calero ◽  
Jordi Martí
Keyword(s):  
Free Energy ◽  
Infinite Dilution ◽  
Sodium Ion ◽  
Water Molecules ◽  
Sodium Ions ◽  
Energy Landscapes ◽  
Membrane Surfaces ◽  
Additional Water ◽  
Free Energy Landscapes ◽  
Typical Configuration

Typical configuration of two DMPC lipids and one cholesterol molecule solvating one sodium ion, together with two additional water molecules.

FURTHER STUDIES ON THE BINDING OF γ-AMINOBUTYRIC ACID BY BRAIN

1967 ◽  
Vol 45 (12) ◽  
pp. 1795-1807 ◽  
Author(s):  
Paula Strasberg ◽  
K. A. C. Elliott
Keyword(s):  
Rat Brain ◽  
Mitochondrial Fraction ◽  
Sodium Ion ◽  
The Other ◽  
Aminobutyric Acid ◽  
Sodium Ions ◽  
Ninhydrin Reaction ◽  
Gaba Content

Factors which can interfere with the paper chromatographic – ninhydrin method for determining γ-aminobutyric acid (GABA) are described. The GABA–ninhydrin reaction does not involve loss of CO2. GABA that is occluded in subcellular particles in plain sucrose homogenates of rat brain does not readily exchange with radioactive GABA in solution. The relevant particles are found mostly in the "mitochondrial fraction". These particles deteriorate with time and manipulations, and tend to lose much of their GABA content. The presence of sodium (but not of potassium, calcium, or magnesium) in the suspending medium allows considerably more GABA to be bound. The extra bound GABA is exchangeable with free labelled GABA. Sodium also promotes some exchange between free and occluded GABA. It is concluded from the present and previous results that in brain in vivo very little GABA exists in a freely diffusing situation. There are two forms of bound GABA. One of these is an occluded or storage form which does not readily exchange with free GABA though exchange is to some extent promoted by sodium ions. The other is a form which occurs only in the presence of sodium ion and is freely exchangeable with GABA in solution.

The Effect of Enzymatic Depolymerization of Arterial Mucopolysaccharides on Sodium Ion Content and Vessel Reactivity

1971 ◽  
Vol 40 (4) ◽  
pp. 293-303 ◽  
Author(s):  
G. S. Harris ◽  
W. A. Palmer
Keyword(s):  
Cation Binding ◽  
Sodium Ion ◽  
Sodium Ions ◽  
High Concentration ◽  
Ion Content ◽  
Binding Properties ◽  
Arterial Walls ◽  
Testicular Hyaluronidase ◽  
Enzymatic Depolymerization

1. The presence of mucopolysaccharides within arterial walls may be associated with the high concentration of sodium ions within this tissue. These polyanions are sensitive to enzymatic depolymerization which results in a loss of the cation binding properties of the molecule. 2. In this study testicular hyaluronidase perfused through isolated arterial segments resulted in a decrease in reactivity of the artery to 65% that of control arteries. Associated with this finding was a 33% decrease in the sodium ion content of the stimulated hyaluronidase-treated artery. When a variety of other sympathetically innervated tissues were treated with hyaluronidase there was no decrease in reactivity or sodium ion content.

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