Glial uptake of neurotransmitter glutamate from the extracellular fluid studied in vivo by microdialysis and 13C NMR

Abstract Background White matter hyperintensities (WMHs) are one of the hallmarks of cerebral small vessel disease (CSVD), but the pathological mechanisms underlying WMHs remain unclear. Recent studies suggest that extracellular fluid (ECF) is increased in brain regions with WMHs. It has been hypothesized that ECF accumulation may have detrimental effects on white matter microstructure. To test this hypothesis, we used cerebral autosomal-dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) as a unique CSVD model to investigate the relationships between ECF and fiber microstructural changes in WMHs. Methods Thirty-eight CADASIL patients underwent 3.0 T MRI with multi-model sequences. Parameters of free water (FW) and apparent fiber density (AFD) obtained from diffusion-weighted imaging (b = 0 and 1000 s/mm2) were respectively used to quantify the ECF and fiber density. WMHs were split into four subregions with four levels of FW using quartiles (FWq1 to FWq4) for each participant. We analyzed the relationships between FW and AFD in each subregion of WMHs. Additionally, we tested whether FW of WMHs were associated with other accompanied CSVD imaging markers including lacunes and microbleeds. Results We found an inverse correlation between FW and AFD in WMHs. Subregions of WMHs with high-level of FW (FWq3 and FWq4) were accompanied with decreased AFD and with changes in FW-corrected diffusion tensor imaging parameters. Furthermore, FW was also independently associated with lacunes and microbleeds. Conclusions Our study demonstrated that increased ECF was associated with WM degeneration and the occurrence of lacunes and microbleeds, providing important new insights into the role of ECF in CADASIL pathology. Improving ECF drainage might become a therapeutic strategy in future.

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Time course of exchanges between red cells and extracellular fluid during CO2 uptake

Journal of Applied Physiology ◽

10.1152/jappl.1975.38.4.710 ◽

1975 ◽

Vol 38 (4) ◽

pp. 710-718 ◽

Cited By ~ 75

Author(s):

R. E. Forster ◽

E. D. Crandall

Keyword(s):

Carbonic Anhydrase ◽

Time Course ◽

Extracellular Fluid ◽

Extracellular Ph ◽

Co2 Uptake ◽

Sudden Increase ◽

Red Cell ◽

Ph Change ◽

Red Cell Membrane

A stopped-flow rapid-reaction apparatus was used to follow the time course of extracellular pH in a human red cell suspension following a sudden increase in PCO2. The extracellular pH change was slow (t1/2 similar to 3.5 s) considering the presence of carbonic anhydrase in the cells. When carbonic anhydrase was added to the extracellular fluid, the half-time was reduced to less than 20 ms. The explanation for these phenomena is that the equilibration of H+ across the red cell membrane is rate-limited by the uncatalyzed reaction CO2 plus H2O formed from H2CO3 outside the cells. A theoretical model was developed which successfully reproduced the experimental results. When the model was used to simulate CO2 exchange in vivo, it was determined that blood PCO2 and pH require long times (greater than 50 s) to approach equilibrium between cells and plasma after leaving an exchange capillary. We conclude that cell-plasma equilibrium may never be reached in vivo, and that in vitro measurements of these quantities may not represent their true values at the site of sampling.

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NEW PHARMACOLOGICALLY ACTIVE COMPOUNDS BASED ON 5-HYDROXY-7-METHOXY-2-PHENYLCHROMAN-4-ONE

Chemical Journal of Kazakhstan ◽

10.51580/2021-1/2710-1185.44 ◽

2021 ◽

Vol 3 ◽

pp. 119-127

Author(s):

G.M. Baisarov ◽

◽

S.M. Adekenov ◽

Keyword(s):

Nmr Spectroscopy ◽

13C Nmr ◽

Potassium Carbonate ◽

13C Nmr Spectroscopy ◽

1H And 13C Nmr ◽

Pharmacologically Active ◽

Pharmacologically Active Compounds ◽

First Time

The reaction of 5-hydroxy-7-methoxy-2-phenylchroman-4-one with dibromoalkanes in acetone in the presence of potassium carbonate proceeds according to the Michael’s retro-reaction O-alkylation and leads to the formation of the corresponding 2-(bromo-alkoxy) chalcones. The structure of the synthesized compounds was confirmed by IR-, 1H- and 13C-NMR spectroscopy. The cytotoxic, hepatoprotective and anti-inflammatory effects of chalcone derivatives (2-3) were studied for the first time in vitro and in vivo.

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Extracellular Fluid Volume Changes in Carcinus Maenas during Acclimation to Low and High Environmental Salinities

Journal of Experimental Biology ◽

10.1242/jeb.99.1.161 ◽

1982 ◽

Vol 99 (1) ◽

pp. 161-173

Author(s):

R. R. HARRIS ◽

M. B. ANDREWS

Keyword(s):

Sea Water ◽

Carcinus Maenas ◽

Extracellular Fluid ◽

Blood Sampling ◽

Extracellular Fluid Volume ◽

Clearance Rates ◽

Volume Changes ◽

Marker Distribution ◽

Water Contents

Changes in extracellular fluid (ECF) volume of Carcinus maenas (L.) were studied in vivo during acclimation to low and high environmental salinities. Initial investigations showed that there was a rapid equilibration into this compartment of the ECF markers used ([3H]inulin and [14C]hydroxymethyl inulin). Earlier reports of a relatively slow marker distribution, indicated from clearance curves, can be explained by high clearance rates occurring when frequent blood sampling was carried out. After transfer of the crabs to media hyposmotic to the haemolymph, ECF volumes decreased transiently to 74.8% of the initial volume, but within 40 h in 26% sea water original volumes were restored. Calculation of intracellular water contents suggests that a volume limitation phase precedes the regulatory return to the original volume. In hyperosmotic media, the ECF volumes increased significantly (to a maximum of 143%) but, in contrast to the response in hyposmotic conditions, showed only a partial return to the original volumes.

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