Search results for "Effects"

Ver�nderungen elektrophysiologischer Me�gr��en des Meerschweinchenherzens bei akuter Trijodthyroninwirkung

1963

Mit intracellularen Mikroelektroden wurden von Vorhof- und Kammermuskulatur von Meerscheinchenherzen Membran- und Aktionspotentiale abgeleitet. Die akute Wirkung von Trijodthyronin (T3 10−6 und 10−5 g/ml) auf diese elektrophysiologischen Mesgrosen wurde untersucht; auserdem wurden Veranderungen der intracellularen K- und Na-Konzentrationen in vitro und in vivo gemessen.

Acute effects of low doses of methyl parathion on human EEG.

2005

Abstract Biological monitoring of workers exposed to organophosphates consists mainly of measuring serum or erythrocyte cholinesterase activity. However, animal experiments and a field study suggest that quantitative analysis of EEG may be more sensitive. In a parallel group design, 25 farmers were investigated, spraying methyl parathion or water for 50 min. EEG was recorded before and after spraying. Serum and erythrocyte cholinesterase activity was compared with intraindividual pre-exposure values. Plasma methyl parathion concentrations ranged up to 12.1 μg/l, methyl paraoxon was not detectable. Based on plasma concentrations, two exposed subgroups were defined. In EEG recorded with close…

Social defeat in adolescent mice increases vulnerability to alcohol consumption

2014

This study employs an oral operant conditioning paradigm to evaluate the effects of repeated social defeat during adolescence on the reinforcing and motivational actions of ethanol in adult OF1 mice. Social interaction, emotional and cognitive behavioral aspects were also analyzed, and real-time polymerase chain reaction (PCR) experiments were performed to study gene expression changes in the mesocorticolimbic and hypothalamus-hypophysis-adrenal (HHA) axis. Social defeat did not alter anxiety-like behavior in the elevated plus maze or cognitive performance in the passive avoidance and Hebb-Williams tests. A social interaction test revealed depression-like symptoms and social subordination b…

Organic carbonates as alternative solvents for asymmetric hydrogenation

2009

Organic carbonates like propylene carbonate (PC) or butylene carbonate (BC) belong to the class of aprotic, highly dipolar solvents (AHD). Interestingly, their potential as solvents for asymmetric catalysis has been overlooked for a long time. The aim of this work is to evaluate organic carbonates and other organic solvents like THF, CH2Cl2, and acetonitrile as well as members of the AHD-family (DMF, DMSO, etc.) as media for homogeneous asymmetric hydrogenation. For this reason cationic Rh-complexes based on chiral phosphine ligands were tested in the hydrogenation of typical benchmark substrates. In several trials, significant advantages of organic carbonates were found. In contrast to DMS…

Research Letter: Structural Combination of Established 5-HT2A Receptor Ligands: New Aspects of the Binding Mode

2010

MH.MZ, MDL 100907, and altanserin are structurally similar 4-benzoyl-piperidine derivatives and are well accommodated to receptor interaction models. We combined structural elements of different high-affinity and selective 5-HT(2A) antagonists, as MH.MZ, altanserin, and SR 46349B, to improve the binding properties of new compounds. Three new derivatives were synthesized with a 4-benzoyl-piperidine moiety as the lead structure. The in vitro affinity of the novel compounds was determined by a [³H]MDL 100907 competition binding assay. The combination of MH.MZ and SR 46349B resulted in a compound (8) with a moderate affinity toward the 5-HT(2A) receptor (K(i) = 57 nm). The remarkably reduced af…

Stereoselective synthesis of substituted tetrahydropyran rings via 6-exo and 6-endo selenoetherification

2002

Eight unsaturated alcohols were cyclized by selenoetherification in 6-exo or 6-endo manner to give substituted tetrahydropyran rings. Yields, regio- and stereoselectivities were discussed in terms of steric and electroniceffects such as Se-O interaction. For the first time examples of the use of silica gel in selenoetherification and the effect of the X - counter ion of PhSe + on the reaction course are discussed. These effects are related to the occurrence of Se-O interaction.

Valproate and GABAergic system effects.

2003

Guanine inhibits the growth of human glioma and melanoma cell lines by interacting with GPR23

2022

Guanine-based purines (GBPs) exert numerous biological effects at the central nervous system through putative membrane receptors, the existence of which is still elusive. To shed light on this question, we screened orphan and poorly characterized G protein-coupled receptors (GPRs), selecting those that showed a high purinoreceptor similarity and were expressed in glioma cells, where GBPs exerted a powerful antiproliferative effect. Of the GPRs chosen, only the silencing of GPR23, also known as lysophosphatidic acid (LPA) 4 receptor, counteracted GBP-induced growth inhibition in U87 cells. Guanine (GUA) was the most potent compound behind the GPR23-mediated effect, acting as the endpoint eff…

Evaluation of the acute toxicity, analgesic and CNS activities of different species ofTeucrium genus

1995

Methanol and dichloromethanol extracts of the leaves and stems of four Teucrium species (T. cartaginenses, T. flavum, T. pumillum and T. buxifolium) have been tested for their toxicity, analgesic and central depressor effects. The intraperitoneal administration of the different extracts showed a CNS depressant activity in mice, but they lacked anticonvulsive effects. When tested for analgesic activity none of the extracts increased the threshold of pain thermal stimulus. However, the methanol and dichloromethanol extracts of T. cartaginenses and T. buxifolium species showed a significant analgesic effect in models of pain induced by chemical or mechanical stimulation.

The effect of β-methylation on the conformation of α, β-dehydrophenylalanine: a DFT study

2009

Dehydroamino acids are non-coded amino acids that offer unique conformational properties. Dehydrophenylalanine (ΔPhe) is most commonly used to modify bioactive peptides to constrain the topography of the phenyl ring in the side chain, which commonly serves as a pharmacophore. The Ramachandran maps (in the gas phase and in CHCl3 mimicking environments) of ΔPhe analogues with methyl groups at the β position of the side chain as well as at the C-terminal amide were calculated using the B3LYP/6-31 + G** method. Unexpectedly, β-methylation alone results in an increase of conformational freedom of the affected ΔPhe residue. However, further modification by introducing an additional methyl group a…