7Li NMR study of normal human erythrocytes

Pettegrew, Jay W.; Post, Jan F. M.; Panchalingam, K.; Withers, Gregory P.; Woessner, D. E.

doi:10.1016/0022-2364(87)90250-2

Cited by 34 publications

(46 citation statements)

References 38 publications

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“…For Li+-loaded RBC, intracellular 7Li TI values were much longer than TZ values; a similar difference in Li+ relaxation times was observed with Li+-agar mixtures (Pettegrew et al, 1987a). Because a large difference in 7Li NMR relaxation times was observed for both Li+-loaded RBCs and agar mixtures, Pettegrew et al (1987a) speculated that diffusion of the Li+ ion across the heterogeneous electrostatic field gradients generated by the spectrinactin (SA) network of the RBC membrane was responsible for this phenomenon. However, the 'Li relaxation properties of the SA network were not tested directly as in this study; binding of Li+ to the cytoskeletal network or to other anionic RBC components could not be ruled out by the previous 7Li NMR studies (Pettegrew et al, 1987a).…”

mentioning

confidence: 88%

“…Studies on Li+ binding to Hb have been reported previously (Bull et al, 1973;Pettegrew et al, 1987a) and have shown very weak Li+-Hb interactions. We have confirmed these observations by measuring 7Li Ti and T2 relaxation times for freshly prepared 2.7 mM COHb, deoxyHb, and metHb solutions containing 1.5-8.0 mM Li+ (Table I).…”

Section: Li+-loaded Rbcs Measurements Of Intracellular 7li+mentioning

confidence: 99%

“…Because a large difference in 7Li NMR relaxation times was observed for both Li+-loaded RBCs and agar mixtures, Pettegrew et al (1987a) speculated that diffusion of the Li+ ion across the heterogeneous electrostatic field gradients generated by the spectrinactin (SA) network of the RBC membrane was responsible for this phenomenon. However, the 'Li relaxation properties of the SA network were not tested directly as in this study; binding of Li+ to the cytoskeletal network or to other anionic RBC components could not be ruled out by the previous 7Li NMR studies (Pettegrew et al, 1987a). Fluorescence anisotropy measurements (Pettegrew et al, 1987b) showed that the presence of Li+ ion may have increased the mobility of RBC membrane surface molecules and the surrounding water structure.…”

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confidence: 99%

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Lithium-7 NMR relaxation study of lithium binding in human erythrocytes

Rong¹,

Espanol²,

Freitas³

et al. 1993

Biochemistry

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ABSTRACT:We used 7Li N M R spin-lattice (TI) and spin-spin (Tz) relaxation time measurements to investigate the binding of Li+ in human red blood cell (RBC) suspensions. In RBCs containing 1.4 mM Li+, the intracellular 7Li N M R T2 relaxation value (0.30 f 0.03 s) was much smaller than the corresponding TI value (6.0 f 0.1 s), yielding a ratio of TI to T 2 of 20. For 1.5 mM LiCl solutions whose viscosities were adjusted to 5 CP with glycerol, the values of the T1/T2 ratios were as follows: 49 for unsealed RBC membrane (2.0 mg of protein/mL); 4.4 for spectrin (1.9 mg/mL); 1.5 for 5.4 mM 2,3-bisphosphoglycerate (BPG); 2.2 for 2.7 mM carbonmonoxyhemoglobin (COHb); 1.6 for 2.0 mM ATP; and 1.2 for a 50/50% (v/v) glycerol-water mixture. Intracellular viscosity and the electric field gradients experienced by Li+ when traversing the spectrin-actin network therefore are not responsible for the large values of the Tl/ T2 ratios observed in Li+-loaded RBCs. We conclude that the RBC membrane is the major Li+ binding site in Li+-loaded RBCs (KI, = 215 f 36 M-l) and that the binding of Li+ to COHb, BPG, spectrin-actin, or ATP is weak. Partially relaxed 7Li N M R spectra of Li+-containing RBC membrane suspensions indicated the presence of two relaxation components, one broad and one narrow. At the same extravesicular Li+ and protein concentrations, the TI values for right-side-out RBC vesicle suspensions were at least 2-fold larger than those for inside-out RBC vesicle suspensions; the inner layer of the RBC membrane, which has a larger percentage of anionic phospholipids than the outer layer, contributes mostly to Li+ binding.

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mentioning

confidence: 88%

Section: Li+-loaded Rbcs Measurements Of Intracellular 7li+mentioning

confidence: 99%

mentioning

confidence: 99%

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Lithium-7 NMR relaxation study of lithium binding in human erythrocytes

Rong¹,

Espanol²,

Freitas³

et al. 1993

Biochemistry

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“…It has been suggested that alterations in membrane molecular dynamics could contribute to the pathophysiology of some patients with bipolar affective illness. [136][137][138][139][140] Other studies suggest that altered activity of membrane phospholipases (especially A 2 ) could contribute to some of the functional membrane changes observed in some patients with affective illness (reviewed in Hibbeln et al 141 ). Pettegrew et al 142 demonstrated distinct alterations in erythrocyte membrane molecular dynamics of affective bipolar patients consisting of increased molecular motion of the phospholipid head group and hydrocarbon core areas of the membrane; those changes were modulated toward normal after 4 weeks of psychotropic treatment.…”

Section: Evidence For Alterations In Membrane Molecular Dynamics In Amentioning

confidence: 99%

“…115,136,[138][139][140]142 The alteration in membrane molecular dynamics, in turn, results in altered function of membrane proteins, such as receptors, ion channels, G-proteins, or second messenger molecular cascades. Since all of these membrane molecular constituents are highly interactive both structurally and functionally, many different molecular alterations could produce the same clinical phenotypes associated with affective disorders.…”

Section: Evidence For Alterations In Membrane Molecular Dynamics In Amentioning

confidence: 99%

Acetyl-L-carnitine physical-chemical, metabolic, and therapeutic properties: relevance for its mode of action in Alzheimer's disease and geriatric depression

2000

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Acetyl-L-carnitine (ALCAR) contains carnitine and acetyl moieties, both of which have neurobiological properties. Carnitine is important in the ␤-oxidation of fatty acids and the acetyl moiety can be used to maintain acetyl-CoA levels. Other reported neurobiological effects of ALCAR include modulation of: (1) brain energy and phospholipid metabolism; (2) cellular macromolecules, including neurotrophic factors and neurohormones; (3) synaptic morphology; and (4) synaptic transmission of multiple neurotransmitters. Potential molecular mechanisms of ALCAR activity include: (1) acetylation of -NH 2 and -OH functional groups in amino acids and N terminal amino acids in peptides and proteins resulting in modification of their structure, dynamics, function and turnover; and (2) acting as a molecular chaperone to larger molecules resulting in a change in the structure, molecular dynamics, and function of the larger molecule. ALCAR is reported in double-blind controlled studies to have beneficial effects in major depressive disorders and Alzheimer's disease (AD), both of which are highly prevalent in the geriatric population. Molecular Psychiatry (2000) 5, 616-632.

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Nuclear magnetic resonance studies of cesium-133 in the halophilic halotolerant bacterium Ba1. Chemical shift and transport studies

Sakhnini

Gilboa

1998

NMR Biomed.

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Ba1 bacteria (Holomonas israelensis ) were grown on different salt concentrations 0.2–4 M. When the cells were transferred to a medium containing 25 mM CsCl without potassium there was an uptake of cesium by the cells. The intracellular cesium signal was shifted from the cesium signal in the medium without the use of a shift reagent. The shift was depended on the salt concentration in the growth medium. The intracellular cesium shift showed a much smaller dependence on the concentration of salts in the medium than the extracellular cesium; the same results were detected for cells grown on a medium containing 25 mM CsCl. The cesium transport through the cell membrane was mostly by active transport. The cesium concentration in the cell was higher than that of the medium, ∼100 mM intracellular concentration compared to 25 mM in the medium. The first order constants for influx or efflux of cesium were from 2 × 10−4 and up to 24 × 10−4 /min for the different medium concentrations. © 1998 John Wiley & Sons, Ltd.

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7Li NMR study of normal human erythrocytes

Cited by 34 publications

References 38 publications

Lithium-7 NMR relaxation study of lithium binding in human erythrocytes

Lithium-7 NMR relaxation study of lithium binding in human erythrocytes

Acetyl-L-carnitine physical-chemical, metabolic, and therapeutic properties: relevance for its mode of action in Alzheimer's disease and geriatric depression

Nuclear magnetic resonance studies of cesium-133 in the halophilic halotolerant bacterium Ba1. Chemical shift and transport studies

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