101 research outputs found
In Vitro Interaction of Lithium on Phospholipids in Human Erythrocytes
Lithium salts are used in the treatment of mania and as prophylaxis against manic depressive disorder. The aim of these studies was the in vitro investigation of the effect of lithium on phospholipids of human erythrocyte membranes. Erythrocytes were treated with lithium for 1 h. Phospholipids phosphatidylinositol (PI), phosphatidylserine (PS), phosphatidylethanolamine (PE), and phosphatidylocholine (PC) were separated from erythrocyte ghosts and determined by HPLC. Blood samples from healthy adults were investigated. A very strong decrease in PC content in erythrocyte membranes due to lithium in vitro treatment was found, as well as a statistically significant increase in PI content
Geogenic and atmospheric sources for volatile organic compounds in fumarolic emissions from Mt. Etna and Vulcano Island (Sicily, Italy)
In this paper, fluid source(s) and processes controlling the chemical composition of volatile organic compounds (VOCs) in gas discharges from Mt. Etna and Vulcano Island(Sicily, Italy) were investigated. The main composition of the Etnean and Volcano gas emissions is produced by mixing, to various degrees, of magmatic and hydrothermal components. VOCs are dominated by alkanes, alkenes and aromatics, with minor, though significant, concentrations of O-, S- and Cl(F)-substituted compounds. The main mechanism for the production of alkanes is likely related to pyrolysis of organic-matterbearing sediments that interact with the ascending magmatic fluids. Alkanes are then converted to alkene and aromatic compounds via catalytic reactions (dehydrogenation and dehydroaromatization, respectively). Nevertheless, an abiogenic origin for the light hydrocarbons cannot be ruled out. Oxidative processes of hydrocarbons at relatively high temperatures and oxidizing conditions, typical of these volcanic-hydrothermal fluids, may explain the production of alcohols, esters, aldehydes, as well as O- and S-bearing heterocycles. By comparing the concentrations of hydrochlorofluorocarbons (HCFCs) in the fumarolic discharges with respect to those of background air, it is possible to highlight that they have a geogenic origin likely due to halogenation of both methane and alkenes. Finally, chlorofluorocarbon (CFC) abundances appear to be consistent with background air, although the strong air contamination that affects the Mt. Etna fumaroles may mask a possible geogenic contribution for these compounds. On the other hand, no CFCs were detected in the Vulcano gases, which are characterized by low air contribution. Nevertheless, a geogenic source for these compounds cannot be excluded on the basis of the present data
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Choline Transport and the Regulation of Acetylcholine Synthesis in Synaptosomes
In recent years evidence has accumulated supporting the proposal that the transport of choline (Ch) into nerve endings by the high affinity transport system may be the rate limiting step in acetylcholine (ACh) synthesis (for reviews see 6,9). We have investigated the interconnections between Ch transport and ACh synthesis with primary interest in: 1) the nature of the coupling between the high affinity transport of Ch and its acetylation catalyzed by choline acetyltransferase (ChAT), 2) in testing the possible existence of an intracellular pool of free Ch available for acetylation in nerve endings, and 3) in investigating the effects of varying extracellular concentrations of Ch on the synthesis and release of ACh
REGULATION OF ACETYLCHOLINE SYNTHESIS: CONTROL OF CHOLINE TRANSPORT AND ACETYLATION IN SYNAPTOSOMES
— The high affinity transport of choline (Ch) and the synthesis of acetylcholine (ACh) were measured in synaptosomes by measuring the utilization of [2H4]Ch. The synthesis of ACh was reduced under several conditions which reduce the availability of acetyl coenzyme A (AcCoA) including no glucose added, replacement of glucose with succinate or impairment of glucose utilization by bromopyr‐uvate, NaCN, or pentobarbital. These conditions did not reduce the amount of unacetylated [2H4]Ch in the synaptosomes indicating that the high affinity transport of Ch is not directly coupled to the synthesis of ACh
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Regulation of acetylcholine synthesis: does cytoplasmic acetylcholine control high affinity choline uptake?
When brain synaptosomes are obtained from animals that have been injected intravenously with [2H4]choline 1 minute before being killed, their high affinity [3H] choline uptake is correlated inversely with their acetylcholine content and directly with the rate at which they synthesize [2H4]acetylcholine. The control of such choline uptake by the cytoplasmic acetylcholine concentration is proposed as a mechanism regulating acetylcholine synthesis in cholinergic nerve terminals
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EFFECT OF PRETREATMENT UNDER VARIOUS CATIONIC CONDITIONS ON ACETYLCHOLINE CONTENT AND CHOLINE TRANSPORT IN RAT WHOLE BRAIN SYNAPTOSOMES
The effects of different ionic environments were measured on the concentration of acetyl‐choline (ACh) from synaptosomes and their effect on subsequent high affinity choline (Ch) transport and ACh synthesis after resuspension of the synaptosomes in the normal Krebs medium. KCl (40 mM) was used to induce ACh release and reduce synaptosomal ACh content. The effects of Na+ omission, Ca2+ omission, and high Mg2+ on spontaneous (KC1: 4.75 mM) and potassium induced (KC1: 40 mM) ACh release and other cholinergic parameters are presented. The high affinity transport of Ch was more highly correlated with the reciprocal of the ACh level (r= 0.934, P= 9.7 × 10‐4) than with the ACh release rate during preincubation (r= 0.792, P= 3.4 × 10‐2). The results are consistent with the view that the consequences of the various ionic conditions on Ch transport and ACh synthesis are dependent on their effects on intrasynaptosomal ACh levels and only secondarily on synaptosomal ACh release
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