Magnesium concentration in the cerebrospinal fluid of mice and its response to changes in serum magnesium concentration

Sun, Liyuan; Kosugi, Yuki; Kawakami, Emiko; Piao, Ying-shan; Hashimoto, Tokitada; Oyanagi, Kiyomitsu

doi:10.1684/mrh.2009.0186

Cited by 24 publications

(19 citation statements)

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“…In the case of Ca2+, its permeation across choroid plexus epithelium inter-epithelial junctions of the BVCSFB into the ventricular CSF is limited as per the saturation of its rate of accumulation when administered systemically in its free radioactive form, 45Ca2+ (Graziani et al 1967), which is consistent with the saturable second order aspect of restricted permeation across inter-epithelial junction pore complexes; whereas, in the case of magnesium, Mg2+, which has a CI-to-AD ratio of + 6.25 nm -1 and diameter of 0.320 nm, is absolutely restricted to permeation across inter-epithelial junction pore complexes, and for this reason does not accumulate in the CSF to any significant extent (Sun et al 2009). In the case of divalent cations with greater cationicity for size including Ca2+ and Mg2+, permeation across restrictive endothelial and epithelial barriers is in their anionic hydrophile chelated forms, for example, in the case of Mg2+, as Mg2+-citrate.…”

Section: Discussionsupporting

confidence: 58%

Permeation thresholds for hydrophilic small biomolecules across microvascular and epithelial barriers are predictable on basis of conserved biophysical properties

Sarin¹

2015

In Silico Pharmacol.

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PurposeNeutral small hydrophiles are permeable to varying degrees, across the aqueous pores of phospholipid bilayer protein channels, with their potential for permeation into cells being predictable, on the basis of hydrophilicity and size. Here, it is hypothesized that permeation thresholds for small hydrophiles, across capillary zona occludens tight junction and inter-epithelial junction pore complexes are predictable, on the basis of predicted hydrophilicity in context of predicted molecular size and charge distribution, as are those of cations and anions, on the basis of predicted ionization in context of predicted atomic size.MethodsSmall hydrophiles are categorized by charge distribution. 2-dimensional plots of predicted hydrophilic octanol-to-water partition coefficient (HOWPC; unitless) and predicted van der Waals diameter (vdWD; nm) are generated for each category. The predicted HOWPC-to-vdWD ratio (nm-1), and vdWDs for permeable hydrophile at the maximum and minimum HOWPC-to-vdWD, vdWD @ MAXimum HOWPC-to-vdWD and vdWD @ MINimum HOWPC-to-vdWD are determined. For cations and anions, the ionization-to-atomic diameter ratios (CI or AI-to-AD ratios; nm-1) are determined.ResultsPer sizes of mixed and pure polyneutral hydrophiles, the permeation size maximum for hydrophiles across tight junction pore complexes is >0.69 ≤ 0.73 nanometers and across inter-epithelial junction pore complexes is ≥ 0.81 nanometers. For hydrophiles with anionicity or cationicity, the vdWDs @ MAXimum HOWPC-to-vdWD are less than those of mixed and polyneutral hydrophiles across both tight and inter-epithelial junctions, ranges specific to category and junction type. For cations, the permeation threshold across tight junctions is between the CI-to-AD ratio of Na+ (+2.69 nm-1) and CH3-Hg+ (+2.36 nm-1), with CH3-Hg+ and K+ (+2.20 nm-1) being permeable; and for divalent cations, the threshold across inter-epithelial junctions is between the CI-to-AD ratio of Mg2+ (+6.25 nm-1) and Ca2+ (+5.08 nm-1) , Ca2+ being semi-permeable. For anions, the permeation threshold across tight junctions is between the AI-to-AD ratio of Cl- (-4.91 nm-1) and Br- (-4.17 nm-1), and the threshold across inter-epithelial junctions is between the AI-to-AD ratio of F- (-7.81 nm-1) and Cl- (-4.91 nm-1).ConclusionsIn silico modeling reveals that permeation thresholds, of small molecule hydrophiles, cations and anions across junctional pore complexes, are conserved in the physiologic state.Electronic supplementary materialThe online version of this article (doi:10.1186/s40203-015-0009-y) contains supplementary material, which is available to authorized users.

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Section: Discussionsupporting

confidence: 58%

Permeation thresholds for hydrophilic small biomolecules across microvascular and epithelial barriers are predictable on basis of conserved biophysical properties

Sarin¹

2015

In Silico Pharmacol.

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“…Previous studies have shown that [Mg 2+ ] e in CNS is in the range of ~0.8–1.2 mM or slightly lower than in plasma (13, 14), but [Mg 2+ ] e homeostasis has received little attention (15). In electrophysiological studies, manipulation of [Mg 2+ ] e is commonly employed, because low [Mg 2+ ] e relieves the depolarization block of the N-methyl-D-aspartate (NMDA) receptors and facilitates induction of LTP and, in more extreme cases, seizure (7, 16).…”

Section: Discussionmentioning

confidence: 99%

Changes in the composition of brain interstitial ions control the sleep-wake cycle

Ding

O’Donnell

et al. 2016

Science

329

366

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Wakefulness is driven by the widespread release of neuromodulators by the ascending arousal system. Yet, it is unclear how these substances orchestrate state-dependent, global changes in neuronal activity. Here we show that neuromodulators induce increases in the extracellular K+ concentration ([K+]e) in cortical slices electrically silenced by tetrodotoxin. In vivo, arousal was linked to AMPA receptor-independent elevations of [K+]e concomitant with decreases in [Ca2+]e, [Mg2+]e, [H+]e, and the extracellular volume. Opposite, natural sleep and anesthesia reduced [K+]e, while increasing [Ca2+]e, [Mg2+]e, [H+]e, as well as the extracellular volume. Local cortical activity of sleeping mice could be readily converted to the stereotypical EEG pattern of wakefulness by simply imposing a change in the extracellular ion composition. Thus, extracellular ions control the state-dependent patterns of neural activity.

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“…In contrast to these negative results, a high-magnesium diet (approximately 1,000 mg/kg/day) resulted in increased serum and erythrocyte magnesium levels in the mouse, and had therapeutic benefits in reduction of anemia (127). Serum levels are perhaps more amenable to dietary manipulation than cerebral spinal fluid (CSF) as CSF levels did not increase with increased serum magnesium level (128). The Diet B formulation used in this study included 4.5 g/kg active magnesium, after accounting for salt weight (see Table 1).…”

Section: Discussionmentioning

confidence: 99%

Nutrient-enhanced diet reduces noise-induced damage to the inner ear and hearing loss

Prell

Gagnon

Bennett

et al. 2011

Translational Research

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Oxidative stress has been broadly implicated as a cause of cell death and neural degeneration in multiple disease conditions; however, the evidence for successful intervention with dietary antioxidant manipulations has been mixed. In this study, we investigated the potential for protection of cells in the inner ear using a dietary supplement with multiple antioxidant components, selected for their potential interactive effectiveness. Protection against permanent threshold shift (PTS) was observed in CBA/J mice maintained on a diet supplemented with a combination of β-carotene, vitamins C and E, and magnesium when compared to PTS in control mice maintained on a nutritionally complete control diet. Although hair cell survival was not enhanced, noise-induced loss of Type II fibrocytes in the lateral wall was significantly reduced (p<0.05), and there was a trend towards less noise-induced loss in strial cell density in animals maintained on the supplemented diet. Taken together, our data suggest that pre-noise oral treatment with the high-nutrient diet can protect cells in the inner ear and reduce PTS in mice. Demonstration of functional and morphological preservation of cells in the inner ear with oral administration of this antioxidant supplemented diet supports the possibility of translation to human patients, and suggests an opportunity to evaluate antioxidant protection in mouse models of oxidative stress-related disease and pathology.

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Magnesium concentration in the cerebrospinal fluid of mice and its response to changes in serum magnesium concentration

Cited by 24 publications

References 0 publications

Permeation thresholds for hydrophilic small biomolecules across microvascular and epithelial barriers are predictable on basis of conserved biophysical properties

Permeation thresholds for hydrophilic small biomolecules across microvascular and epithelial barriers are predictable on basis of conserved biophysical properties

Changes in the composition of brain interstitial ions control the sleep-wake cycle

Nutrient-enhanced diet reduces noise-induced damage to the inner ear and hearing loss

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