Search Results
Results 151 - 200 of 540
1 2 3 4 5 6 7 8 9 10 >
Hu Ming-Kuan - - 2002
In the search for highly selective and potent derivatives of tacrine (1a), a number of homodimeric tacrine congeners were synthesized and conducted for their effects on rat acetylcholinesterase (AChE) and human butyrylcholinesterase (BChE) inhibitions. Heptylene-linked bis-(6-chloro)tacrine (3h) was found up to 3000- and 3-fold more potent in inhibiting rat AChE ...
De Visscher Geofrey - - 2002
In this study, near-infrared spectroscopy was applied to examine whether cytochrome oxidase in the rat brain is inhibited by nitric oxide in vivo. During normoxia, intravenous N(G)-nitro-L-arginine methyl ester (L-NAME) administration significantly decreased the cerebral saturation of hemoglobin with oxygen but did not alter the cytochrome oxidase redox state. Anoxia ...
Tachibana T - - 2002
1. We measured the concentrations of dopamine (DA), norepinephrine (NE), epinephrine (E) and 5-hydroxytryptamine (5-HT) in the hypothalamus of 21-d-old male brown-egg layer-type chicks after intracerebroventricular injection of glucagon-like peptide-1 (GLP-1). 2. The monoamine concentrations of the whole hypothalamus, paraventricular nucleus and lateral hypothalamic area were not significantly affected by ...
Koizumi Miwako - - 2002
The effect of enterostatin injection into the rat lateral hypothalamic area (LHA) on serotonin and dopamine releases in extracellular space was investigated by in vivo microdialysis technique. The primary focus being to understand whether a small amount of enterostatin crossing the blood-brain barrier correlates with activity changes in serotonergic and ...
Hurtado-Guzmán C - - 2002
Monoamine oxidase-A (MAO-A) [amiflamine (AMF) and 4-methylthioamphetamine (MTA)] and MAO-B (L-deprenyl) inhibitors were found to be cytotoxic in a concentration-dependent manner for RCHT cells derived from adult rat hypothalamus. The cytotoxic effects were increased when the inhibitors were co-incubated with dicoumarol and especially with 25 micro M AMF+100 micro M ...
Lenda Deborah M - - 2002
Increased salt intake attenuates the endothelium-dependent dilation of skeletal muscle arterioles by abolishing local nitric oxide (NO) activity. There is evidence of oxidative stress in arteriolar and venular walls of rats fed a high-salt diet, and depressed arteriolar responses to acetylcholine (ACh) in these rats are reversed by scavengers of ...
Kosel M - - 2002
This study was conducted to identify enzyme systems eventually catalysing a local cerebral metabolism of citalopram, a widely used antidepressant of the selective serotonin reuptake inhibitor type. The metabolism of citalopram, of its enantiomers and demethylated metabolites was investigated in rat brain microsomes and in rat and human brain mitochondria. ...
Obata T - - 2001
The present study examined the antioxidant effect of histidine, a singlet oxygen ((1)O(2)) scavenger, on para-nonylphenol (an environmental estrogen-like chemical)-enhanced hydroxyl radical (.OH) generation induced by 1-methyl-4-phenylpyridinium ion (MPP+) in extracellular fluid of rat striatum. Rats were anesthetized, and sodium salicylate in Ringer's solution (0.5 nmol/microl/min) was infused through a ...
Shim S H SH Department of Applied Biological Chemistry, Faculty of Agriculture, Utsunomiya University, 350 Mine, Utsunomiya 321-8505, - - 2001
We compared tyrosine hydroxylase immunoreactivity in the substantia nigra and hypothalamus of hereditary microphthalmic rats with that of normal rats. A considerable number of neuronal cell bodies expressing tyrosine hydroxylase were present in the substantia nigra of the microphthalmic mutant as well as normal rats. Neuronal cells positive for tyrosine ...
Lee E S - - 2001
1-Methyl-4-phenyl-pyridinium (MPP(+)) and S-adenosyl-L-methionine (SAM) cause Parkinson's disease (PD)-like changes. SAM and MPP(+) require their charged S-methyl and N-methyl groups, so the PD-like symptoms may be related to their ability to modulate the methylation process. The SAM-dependent methylation of phosphatidylethanolamine (PTE) to produce phosphatidylcholine (PTC), via phosphatidylethanolamine-N-methyltransferase (PEMT), and the ...
Huotari M M Department of Pharmacology and Toxicology, University of Kuopio, P.O. Box 1627, FIN-70211, Kuopio, Finland. - - 2001
6-Nitronoradrenaline, a bioactive compound recently identified in the brain, is known to inhibit catechol-O-methyltransferase. To study its effect on dopamine metabolism, it was administered into rat striatum via a microdialysis probe. Other nitrated catechols (6-nitrodopamine, 6-nitro-DOPAC and 5-nitro-HVA) were studied for comparison. Tolcapone, a selective catechol-O-methyltransferase inhibitor, was used as ...
Nag M - - 2001
Organophosphate (OP) pesticides, monocrotophos (MCP), dichlorvos (DDVP) and phosphamidon significantly inhibit both MAO-A and MAO-B activities in rat brain mitochondria. The inhibition of MAO-A by MCP is reversible whereas the inhibition by DDVP and phosphamidon is irreversible. MAO-B is inhibited irreversibly by all these organophosphates suggesting that the mechanism of ...
Amaki S K - - 2001
The nitrogen cycle initiates direct reduction of N2 to NH3 by enzymatic reactions. We hypothesize that L-dihydroxyphenylalanine (L-DOPA), a catecholamine, could be a source of nitric oxide (NO). In order to determine whether L-DOPA generates NO and induces any biological change in the eye, we measured the generation of NO ...
Obata T - - 2001
We recently demonstrated that para-nonylphenol, an environmental estrogen-like chemical, enhances hydroxyl radical (*OH) generation in the rat striatum. In the present study we have examined whether para-nonylphenol enhanced 1-methyl-4-phenylpyridinium ion (MPP(+))-induced *OH generation in the rat striatum using a microdialysis technique. Para-nonylphenol significantly enhanced MPP(+)-induced *OH generation. Further, we studied ...
Ali S - - 2001
Xanthine oxidase (XO) generates reactive oxygen metabolites (ROM) as a by-product while catalyzing their reaction. The present study implicates these ROM in the pathogenesis of liver necrosis produced in rats by the intraperitoneal administration of thioacetamide (TAA; 400 mg/kg b.wt.). After 16 h of TAA administration, the activity of rat ...
Andrés N - - 2001
Semicarbazide-sensitive amine oxidase (SSAO), widely distributed in highly vascularized mammalian tissues, metabolizes endogenous and xenobiotic aromatic and aliphatic monoamines. To assess whether its physiological role in humans is restricted to oxidation, we used an immunohistochemical approach to examine the cellular localization of SSAO in human peripheral tissues (adrenal gland, duodenum, ...
Keung W M - - 2001
Daidzin, a major active principle of an ancient herbal treatment for 'alcohol addiction', was first shown to suppress ethanol intake in Syrian golden hamsters. Since then this activity has been confirmed in Wistar rats, Fawn hooded rats, genetically bred alcohol preferring P rats and African green moneys under various experimental ...
van Staveren - - 2001
The effects of selective and non-selective 3',5'-cyclic nucleotide phosphodiesterase (PDE) inhibitors on cGMP and cAMP accumulation were studied in rat hippocampal slices incubated in vitro. The following PDE inhibitors were used: vinpocetine and calmidazolium (PDE1 selective), erythro-9-(2-hydroxy-3-nonyl)adenine (EHNA, PDE2 selective), SK&F 95654 (PDE3 selective), rolipram (PDE4 selective), SK&F 96231 (PDE5 ...
Hatsuda S - - 2001
Using microdialysis, extracellular concentrations of 5-hydroxytryptamine (5-HT) and 5-hydroxyindoleacetic acid (5-HIAA) were determined in the striatum of rats. In rats given trazodone, m-chlorophenylpiperazine dihydrochloride, or imipramine, the concentrations of 5-HT were unchanged. 5-HIAA in trazodone- or imipramine-treated rats, however, was respectively, decreased to 80 or 65% of preinjections levels. When ...
Obata T - - 2000
An endogenous inhibitor of semicarbazide-sensitive amine oxidase (SSAO) was separated by gel filtration from 105000xg supernate in rat brain cytosol following immobilization stress (IMMO). The molecular weight of this inhibitor was estimated to be 500-700 by gel filtration. This inhibitor was proved to be heat-stable resistant to protease treatment. These ...
Pan X - - 2000
AIM: To study the inhibition of liquiritigenin (1) and isoliquiritigenin (2) isolated from Sinofranchetia chinensis on rat monoamine oxidase A and B (MAO A and B). METHODS: Rat brain mitochondrial fraction, prepared by differential centrifugation, was utilized as a source of MAO activity. MAO activity was determined radiochemically with [14C]5-hydroxytryptamine ...
Bringmann G - - 2000
The mammalian alkaloids tryptoline (1) and eleagnine (2) as well as the highly halogenated (X = F, Cl, Br) tetrahydro-beta-carbolines (THbetaCs) 3-5, structurally similar to the dopaminergic neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP, 6), were found to have a common feature of inducing a severe impairment of the nigrostriatal dopamine metabolism and inhibiting ...
Lamensdorf I - - 2000
3,4-Dihydroxyphenylacetaldehyde (DOPAL) has been reported to be a toxic metabolite formed by the oxidative-deamination of dopamine (DA) catalyzed by monoamine oxidase. This aldehyde is either oxidized to 3,4-dihydroxyphenylacetic acid (DOPAC) by aldehyde dehydrogenase, an NAD-dependent enzyme or reduced to 3, 4-dihydroxyphenylethanol (DOPET) by aldehyde or aldose reductase. In the present ...
Fornai F - - 2000
We recently identified the direct product of dopamine (DA) by monoamine-oxidase (MAO) activity, dihydroxyphenylacetaldehyde (DOPALD) in the trans-striatal dialysate. Based on these findings, in this work, we directly measured the variations in DOPALD levels after various kinds of pharmacological treatment in rat striatal extracellular fluid. Using both reversible and irreversible ...
Kishimoto Y - - 2000
We examined by immunohistochemistry the effects of monoamine oxidase (MAO) inhibition on the content of dopamine (DA) and noradrenaline (NA) in locus coeruleus (LC) neurons of the rat. In normal rats, clusters of DA- and NA-immunopositive neurons were identified in the LC. Rats treated with intraperitoneal injections of pargyline, an ...
Durden D A - - 2000
(R)-N-(2-Heptyl)-N-methylpropargylamine (R-2HMP) is a monoamine oxidase inhibitor and putative antiapoptotic agent analogous to (R)-deprenyl. In the rat, the major amine metabolites of R-2HMP have been identified as (R)-N-2-heptylmethylamine (R-2HMA), (R)-N-2-heptylpropargylamine (R-2HPA), and (R)-2-heptylamine (R-2HA). After R-2HMP was administered s.c. to male Wistar rats, it was observed that the greatest concentration ...
Andreassen O A - - 2000
Neuroleptic-induced oral dyskinesia in rats, a putative analogue to human tardive dyskinesia, may be due to degeneration within the striatum. Using unbiased stereological methods, a decreased number of striatal neurons expressing preprosomatostatin mRNA was observed only in rats that developed pronounced oral dyskinesias after 30 weeks of haloperidol administration. The ...
Kostrzewa R M - - 2000
To determine if greater amounts of hydroxyl radical (*OH) are formed by dopamine (DA) denervation and treatment with L-dihydroxyphenylalanine (L-DOPA), the neostriatum was DA denervated (99% reduction in DA content) by 6-hydroxydopamine treatment (134microg icv, desipramine pretreatment) of neonatal rats. At 10 weeks the peripherally restricted dopa decarboxylase inhibitor carbidopa ...
Canevari L - - 1999
Mutations in GTP-cyclohydrolase I (GTP-CH) have been identified as causing a range of inborn errors of metabolism, including dopa-responsive dystonia. GTP-CH catalyses the first step in the biosynthesis of tetrahydrobiopterin (BH4), a cofactor necessary for the synthesis of catecholamines and serotonin. Current therapy based on monoamine neurotransmitter replacement may be ...
Kashiwagi A - - 1999
To examine the effects of chronic hyperinsulinemia on vascular tissues, we examined the production of superoxide anion (O(-2)) in the aortic tissues of control and exogenously hyperinsulinemic rats performed by the implantation of an insulin pellet for 4 wk. O(-2) production by aortic segments from hyperinsulinemic rats was 2. 4-fold ...
Shi H - - 1999
We have studied the interaction of coenzyme Q with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) and its metabolites, 1-methyl-4-phenyl-2,3-dihydropyridinium (MPDP(+)) and 1-methyl-4-phenylpyridinium (MPP(+)), the real neurotoxin to cause Parkinson's disease. Incubation of MPTP or MPDP(+) with rat brain synaptosomes induced complete reduction of endogenous ubiquinone-9 and ubiquinone-10 to corresponding ubiquinols. The reduction occurred in ...
Schwille P O - - 1999
Uric acid (UA), a waste product of purine metabolism, may be involved in calcium phosphate crystallization and deposition. Rats, which develop nephrocalcinosis on high-fat or magnesium-deficient diets, and patients with idiopathic calcium urolithiasis have hyperproteinuria, especially of nonalbumin protein, and a shift toward elevated serum UA. In rats, an increase ...
Tunici P - - 1999
Polyamine degradation was studied in the small intestine from rats fed on a polyamine-supplemented diet. Lactalbumin diet was given to Hooded-Lister rats, with or without 5 mg rat(-1) day(-1) of putrescine or spermidine for 5 days. Polyamine oxidase activity increased with putrescine and spermidine in the diet, whereas spermidine/spermine N(1)-acetyltransferase ...
Mukherjee J - - 1999
We have synthesized N-[3-(2',4'-dichlorophenoxy)-2-18F-fluoropropyl]-N-methylpropar gylamine (18F-fluoroclorgyline) as a potential positron emission tomography (PET) radiotracer for monoamine oxidase A (MAO-A). The radiosynthesis was carried out by a 18F-fluoride-for-mesylate substitution reaction in approximately 20% radiochemical yield in specific activities of 1-2 Ci/micromol. Selectivity for MAO-A was demonstrated by the high affinity of ...
Nakamura Y - - 1999
The purpose of the present investigation was to test three calpain inhibitors (recombinant calpastatin domain I, E64, and SJA6017) against Lp82 calpain in rat lenses. Lp82 is a lens-specific isoenzyme from the calpain super family of calcium-activated, cysteine proteases (EC 34.22.17). Lp82 and m-calpain proteolytic activities and protein levels were ...
Kitamura S - - 1999
Converting activity of methotrexate (MTX) to 7-hydroxymethotrexate (7-OH-MTX) was examined using eight strains of rats. Marked variability of the activity was found in liver cytosols from the rats. The highest activity was observed with Sea:SD rats, followed by LEW/Sea and Jcl:Wistar rats. The lowest activity was observed with WKA/Sea rats. ...
Snape M F - - 1999
The in vitro and in vivo effects of the novel acetylcholinesterase inhibitors donepezil and NXX-066 have been compared to tacrine. Using purified acetylcholinesterase from electric eel both tacrine and donepezil were shown to be reversible mixed type inhibitors, binding to a similar site on the enzyme. In contrast, NXX-066 was ...
Horiuchi H - - 1999
In this study, the hypouricemic efficacy of a novel xanthine oxidase/xanthine dehydrogenase inhibitor, TEI-6720, was compared with that of allopurinol in a hyperuricemic rat model established by feeding the animals oxonate, a uricase inhibitor. In addition, using normal rats, the changes in xanthine concentration in plasma and the concentrations and ...
Chakos M H - - 1998
BACKGROUND: Striatal enlargement with chronic neuroleptic treatment in schizophrenic patients has been reported by several investigators. Longitudinal magnetic resonance imaging studies of patients suggest that changes in striatal volume may be caused by treatment with antipsychotic medication. METHODS: We have examined the effects of chronic neuroleptic treatment on postmortem striatal ...
Ferioli M E - - 1998
Given the important role of polyamines (putrescine, spermidine, spermine) in the modulation of macromolecular syntheses, gene expression and proteolysis, alterations in their metabolic pathways could be relevant during senescence. Since the few existing data address mainly polyamine biosynthesis, we studied the oxidative catabolism of polyamines in the liver of rats ...
Yatabe T - - 1998
A novel series of 2,2-dialkyl-5-(2-quinolylmethoxy)-1,2,3, 4-tetrahydro-1-naphthols was synthesized and evaluated as 5-lipoxygenase (5-LO) inhibitors. Systematic optimization led to identification of several highly potent non-redox type 5-LO inhibitors with nanomolar IC50s as racemic mixtures. Optical resolution of racemate 50 indicated that its 5-LO inhibitory activity was enantiospecific and due to the ...
Ivanova S - - 1998
To elucidate endogenous mechanisms underlying cerebral damage during ischemia, brain polyamine oxidase activity was measured in rats subjected to permanent occlusion of the middle cerebral artery. Brain polyamine oxidase activity was increased significantly within 2 h after the onset of ischemia in brain homogenates (15.8 +/- 0.9 nmol/h/mg protein) as ...
Sarabia S F - - 1998
Estrogen-induced kidney tumorigenesis in the male Syrian hamster has been postulated to be mediated by free radicals generated by metabolic redox cycling of catecholestrogen intermediates. This tissue and other rodent tissues in which tumors develop in response to estrogen treatment have been shown to contain high levels of the catecholamine ...
Huh K - - 1998
The effect of thyroid hormones on the hepatic xanthine oxidase activity was studied in rats after the intraperitoneal injections of comthyroid (triiodotyronine:thyroxine = 1:4) at 0.3 mg/kg for 3 consecutive days. The aim of this study was to understand the precise mechanism of hyperthyroidism induced by oxidative stress. The concentration ...
Guilloteau D - - 1998
For the diagnosis and follow-up of neurodegenerative diseases, many cocaine derivatives have been proposed as radioligands to explore the dopamine transporter. As none of them have all the criteria of specificity and kinetics for human use, we have developed a new derivative, (E)-N-(3-iodoprop-2-enyl)-2beta-carbomethoxy-3beta-(4'-methy lphenyl)nortropane (PE2I), which displays promising properties. We ...
Enrique-Tarancón G - - 1998
The previous characterization of an abundant population of non-adrenergic imidazoline-I2 binding sites in adipocytes and the recent demonstration of the interplay between these binding sites and amine oxidases led us to analyze the amine oxidase activity in membranes from isolated rat adipocytes. Adipocyte membranes had substantial levels of semicarbazide-sensitive amine ...
Hu Y Q - - 1998
Previous studies have implicated human alpha-2-macroglobulin (alpha2M) as a potential regulator of neuronal development and function. Rat alpha-1-macroglobulin (alpha1M) and acute-phase alpha-2-macroglobulin (alpha2M) are murine homologues of human alpha2M. In this report, we tested the effect of intracranially infused serotonin-activated rat alpha1M (5HT-alpha1M) on the concentration of dopamine (DA) in ...
Pozdnev V F - - 1998
A series of urethane type derivatives of ethylene diamine (EDA) was synthesised and tested as inhibitors of monoamine oxidase (MAO) A and B. Nature of aromatic ring and a position of substituents in it were important for the inhibitory activity. Chlorobenzyloxycarbonyl-EDA derivatives exhibited selective inhibition of MAO-A with 3,4-Cl2-C6H4CH2OCO-EDA being ...
Tsai T R - - 1998
The nanoparticles of physostigmine were prepared by an emulsion polymerization of polyisobutylcyanoacrylate. The drug content, release and particle size distribution of the nanoparticles were characterized. In vitro drug release profiles displayed a retardation by the nanoparticles in comparison to the aqueous solution. Pharmacological evaluation of physostigmine nanoparticles in vivo were ...
Cervinková Z - - 1998
During 48 hours after application sublethal doses of hepatotoxic agent thiacetamide decrease cytochrome c oxidase activity of rat liver homogenate and isolated mitochondria to 46% and 32% of original values, respectively. This decrease may be prevented by simultaneous application of lipid emulsion (mixture of Lipofundin and Mygliol) twice b day.
1 2 3 4 5 6 7 8 9 10 >