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Results 351 - 400 of 540
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Ruiz O - - 1988
The inhibitory effect of a series of 2-alkylputrescines on rat liver and Escherichia coli ornithine decarboxylase (L-ornithine carboxy-lyase, EC 4.1.1.17) was examined. At 2.5 mM concentrations, 2-methyl-, 2-propyl-, 2-butyl-, 2-pentyl- and 2-hexylputrescines were stronger inhibitors of the mammalian enzyme than putrescine. Only the higher homologues (from 2-propyl- to 2-hexylputrescine) were ...
Rodrigues A D - - 1988
The ability of the 1-substituted imidazole antifungal agent clotrimazole to inhibit the rat hepatic microsomal mixed-function oxidases was investigated in rats pretreated with either phenobarbital or 3-methylcholanthrene. When administered to 3-methylcholanthrene-pretreated animals, clotrimazole inhibited the O-deethylations of ethoxyresorufin and ethoxycoumarin. An even more marked inhibition of the dealkylation of pentoxyresorufin ...
Murakami D M - - 1988
This study examined the postnatal development of oxidative metabolism in the rat suprachiasmatic nucleus. The cytochrome oxidase technique was used to reveal the pattern of metabolic development. The cytochrome oxidase reactivity in suprachiasmatic nucleus is above background at birth and coincides with the Nissl-stained borders of the suprachiasmatic nucleus. The ...
Ozaki N - - 1988
We report that 1-methyl-4-phenylpyridinium ion (MPP+), the active metabolite of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), inactivated tyrosine hydroxylase (TH) when MPP+ was directly infused into the striatum. We examined both in vitro TH activity and TH content measured by an enzyme immunoassay in the rat striatum after MPP+ was administered by an in ...
Männistö P T - - 1988
Novel bisubstituted catechols were found to be potent and highly selective COMT inhibitors in vitro. One of them, OR-462 (3-(3,4-dihydroxy-5-benzylidene)-2,4-pentanedione), was studied also in vivo. When administered to rats orally together with levodopa and carbidopa, OR-462 greatly improved the bioavailability of levodopa and effectively reduced the formation of 3OMD. The ...
Usuda N - - 1988
The localization of urate oxidase in different tissues of rat and in the livers of selected mammalian species was investigated by immunoblot analysis and protein A-gold immunoelectron microscopy. Urate oxidase was purified from rat liver and used as an antigen to generate polyclonal antibodies in the rabbit. The antibodies were ...
Fonda M L - - 1988
1. Vitamin B6-sufficient rats had moderate pyridoxamine-P oxidase specific activities in heart, brain, kidney and liver, but no detectable activity in skeletal muscle. Vitamin B6-deficiency in rats resulted in a decreased oxidase activity in liver but no change in the activities in other tissues. 2. The pyridoxamine-P oxidase activity in ...
Marçais-Collado H - - 1987
Thiorphan and acetorphan, two potent inhibitors of enkephalinase (EC 3.4.24.11 membrane-metalloendopeptidase) significantly reduced the castor oil-induced diarrhea in rats when administered intravenously (or orally, for acetorphan) but not when administered intracerebroventricularly. These effects were more marked during the 90 min period following the castor oil challenge but were still significant ...
Björk L - - 1987
The effects of the four possible C3-methylated stereoisomers of 8-hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT) ((-)-CM-11, (+)-CM-11, (-)-CM-12, (+)-CM-12) on brain 5-hydroxytryptamine (5-HT) receptor functions were studied in rats. (-)-CM-11 and (+)-CM-12 inhibited dose dependently in all brain parts the accumulation of 5-hydroxytryptophan following decarboxylase inhibition. Their antipodes were inactive. The disappearance of 5-HT ...
Kalaria R N - - 1987
We studied the monoamine metabolizing mitochondrial enzyme, monoamine oxidase (MAO), in cerebral microvessels obtained from postnatally developing rats by measuring the specific binding of [3H]pargyline, an irreversible inhibitor of MAO, and the rate of oxidation of three known MAO substrates: benzylamine, 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine, and tryptamine. MAO activity increased postnatally, with the ...
Gibson C J - - 1987
The neurotoxin, DSP-4, (N-(2-chloroethyl)-N-ethyl-2-bromobenzylamine hydrochloride) specifically and significantly reduces norepinephrine (NE) and its metabolite, 3-methoxy-4-hydroxyphenylethylene glycol (MHPG), in cortical, hippocampal and cerebellar brain regions. Pretreatment with the selective monoamine oxidase (MAO) B inhibitor, deprenyl, and the non-specific MAO inhibitor, pargyline, effectively blocked NE depletion. Pretreatment with the selective MAO A ...
LaManna J C - - 1987
Rapid-scanning reflectance spectrophotometry was used to evaluate the reduction-oxidation state of cytochrome oxidase in normoxic rat brain. Reflectance spectra were recorded from intact blood-perfused cerebral cortices after increased oxidative metabolic activity induced by direct cortical stimulation. Reflectance spectra taken from blood-free rat brain and from the rat ear vascular bed ...
Yonetani Y - - 1987
Both potassium oxonate and allantoxanamide have been reported as useful reagents for inhibiting urate oxidase, with the hyperuricemic effect of allantoxanamide being longer-lasting than that of oxonate in rats. The present study was done to evaluate the utility of allantoxanamide for investigating problems concerning hyperuricemia using rats. A single intraperitoneal ...
Kalaria R N - - 1987
We studied the enzyme monoamine oxidase (MAO) in isolated cerebral microvessels, and in mitochondria-enriched brain and liver preparations from six mammalian species, including human. We also studied MAO distribution in various tissues and in discrete brain regions of the rat. MAO was assessed by measuring the specific binding of [3H]pargyline, ...
Cumming P - - 1987
[18F]-6-Fluoro-L-DOPA ([18F]DOPA), a tracer for cerebral dopamine in studies utilizing positron emission tomography (PET), is rapidly metabolized by catechol-O-methyltransferase (COMT) in the periphery following intravenous injection to carbidopa-pretreated humans and rats. Experiments were performed to determine the effect of pretreatment with 3',4'-dihydroxy-2-methyl-propiophenone (U-0521), a competitive inhibitor of COMT, on [18F]DOPA ...
Sardar A - - 1987
The concentrations of p-tyramine and m-tyramine have been determined in 6 brain areas from the mesolimbic system by a specific and sensitive mass spectrometric technique. p- and m-Tyramine are unevenly distributed amongst these nuclei. The highest concentrations of p-tyramine were measured in the olfactory tubercle followed by the nucleus accumbens ...
Engerson T D - - 1987
In response to global ischemia, tissue xanthine dehydrogenase was converted to xanthine oxidase in all tissues with half-times of conversion at 37 degrees C of approximately 3.6, 6, 7, and 14 h for the liver, kidney, heart, and lung, respectively. The time course of enzyme conversion at 4 degrees C ...
Dupont H - - 1987
The inhibition of cytochrome P-450 dependent hydroxylations of bufuralol (BH) and antipyrine, and O-deethylation of 7-ethoxycoumarin (7-ECOD) by several monoamine oxidase inhibitors (MAOIs) was investigated in rat liver microsomes. According to their IC50 values, clorgyline was the most potent inhibitor while toloxatone, the only reversible MAOI in this study, was ...
Kalaria R N - - 1987
Systemic administration of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) causes parkinsonism in humans and subhuman primates, but not in rats and many other laboratory animals; mice are intermediate in their susceptibility. Since MPTP causes selective dopaminergic neurotoxicity when infused directly into rat substantia nigra, we hypothesized that systemic MPTP may be metabolized by monoamine ...
Meco M - - 1987
The distribution of monoamine oxidase types A and B in the heart of young (3-month-old) and aged (26-month) Wistar rats was studied by histochemical methods. In young rats, MAO activity was higher in the left ventricle than in the right. Enzyme reactivity was present within both muscle cells and the ...
Ichikawa K - - 1987
The effect of thyroid hormone on peroxisomal enzyme activity was studied in thyroidectomized- and T4-administered-thyroidectomized rats. In liver, the activities of isozyme A of L-alpha-hydroxyacid oxidase, D-amino acid oxidase, urate oxidase and catalase were decreased by thyroidectomy, and the diminished enzyme activities were restored by T4 administration to rats. These ...
Tani Y - - 1987
Monoamine levels were measured by high performance liquid chromatography with electrochemical detection in seven brain regions of three models of experimentally-induced muricide (mouse-killing behavior) in rats (bilateral olfactory bulbectomized rats: OB rats, midbrain raphe nuclei lesioned rats: Raphe rats and nucleus accumbens lesioned rats: Acc rats). Noradrenaline (NA) levels in ...
Hornebeck W - - 1987
Rat leukocyte elastase has been purified successively by AH-Sepharose Kappa-elastin affinity chromatography and by ion exchange chromatography on a carboxymethyl Sephadex resin. It has great similarities with human leukocyte elastase in its molecular weight, substrate specificity and inhibitory profile. The effect of rat leukocyte elastase inhibitors in influencing the chemotactic ...
Dyck L E - - 1987
The concentrations of the trace amines, m-tyramine, p-tyramine, phenylethylamine and tryptamine, were measured in the striatum of the brain and in the kidney of adult rats treated with alpha-monofluoromethyldopa (MFMD), an inhibitor of aromatic amino acid decarboxylase. While MFMD decreased the levels of all four amines in the kidney, only ...
Fukui Y - - 1987
Characteristics of cytochrome oxidase prepared from hearts of Sprague-Dawley male rats were studied with the use of the fourth derivative spectrophotometry in respect to the cytotoxic effects of carbon monoxide (CO). CO-exposed rats tended to show lower specific activities of cytochrome oxidase than control and recovered rats. Moreover, there was ...
Chattha G K - - 1987
Local injection of cysteamine into rat striatum results in a rapid but reversible reduction in somatostatin-like immunoreactivity (SLI). Since somatostatin and neuropeptide Y are co-localized in striatal and cortical neurons, we examined the effects of cysteamine in these areas. SLI and neuropeptide Y-like immunoreactivity (NPYLI) were measured following local injection ...
Vallejo M - - 1987
The effects of intracerebroventricular administration of neuropeptide Y (NPY) on central monoamine turnover were studied in rats treated with alpha-methyl-p-tyrosine (alpha-MPT). NPY decreased noradrenaline turnover in the brainstem, hypothalamus, midbrain and hippocampus. Dopamine turnover was decreased in the brainstem and striatum of NPY-treated rats. Although alpha-MPT did not seem to ...
Kao G Y - - 1987
Dopamine sulfate (DAS) is formed by the action of phenolsulfotransferase (PST) on dopamine (DA). Since probenecid is often used to investigate the transport of monoamine acidic metabolites such as DAS from the brain, we investigated the effect of probenecid on rat brain PST activity utilizing DA as substrate. In the ...
Sandler M - - 1987
1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) administration causes a Parkinson's disease like syndrome in man and primates, with selective degeneration of the substantia nigra. This discovery has raised the possibility that some environmental or endogenous toxin causes idiopathic Parkinson's disease. MPTP is oxidised to its neurotoxic metabolite, 1-methyl-4-phenylpyridinium (MPP+) by monoamine oxidase B (MAO ...
Sardar A - - 1987
These experiments show that in the rat corpus striatum the highest concentrations of p- and m-tyramine were found in the caudate nucleus while somewhat lower values were observed in the putamen and globus pallidus. Inhibition of monoamine oxidase by pargyline produced an increase in the concentration of both tyramines in ...
Gunnison A F - - 1987
We report on the distribution, metabolism, and toxicity of sulfite in the respiratory tract and other tissues of rats exposed to endogenously generated sulfite or to inhaled sulfur dioxide (SO2). Graded sulfite oxidase deficiency was induced in several groups of rats by manipulating their tungsten to molybdenum intake ratio. Endogenously ...
Sabban E L - - 1987
In vivo biosynthesis of the 2 subunit forms of dopamine beta-hydroxylase (DBH) was examined in the rat brain. 35S-methionine was injected into the noradrenergic neurons of the locus coeruleus (LC) using a stereotactic device. Several hours later, newly synthesized 35S-Met-labeled DBH was immunoprecipitated and quantitated. Both Mr = 77,000 (77K) ...
Petkov V D - - 1987
In experiments on 2-, 10- and 22-month old rats, it was found that essential age-related changes occurred in the brain level of biogenic monoamines (BMA) and in the monoamine oxidase (MAO) activity. In 22-month old rats the levels of dopamine (DA), noradrenaline (NA) and serotonin (5-HT) markedly declined in most ...
Worms P - - 1987
SR 95191 [3-(2-morpholino-ethyl-amino)-4-cyano-6-phenyl-pyridazine], a novel compound, has been shown in preliminary experiments to inhibit type A monoamine oxidase (MAO). This report describes the activities of SR 95191 in behavioral experiments in mice and rats and shows that SR 95191 has the profile of a selective type A MAO inhibitor (MAOI). ...
De Ceballos M L - - 1986
Treatment of rats for 18 months with trifluoperazine increased [Met5]- and [Leu5]enkephalin and neurotensin content in striatum and nucleus accumbens. However, in substantia nigra the content of [Met5]enkephalin was decreased, [Leu5]enkephalin unchanged and that of neurotensin increased. Administration of L-DOPA plus carbidopa, bromocriptine or pergolide for 12 months decreased [Met5]enkephalin ...
Buu N T - - 1986
New England Deaconess Hospital rats implanted with a pheochromocytoma P259 became hypertensive and showed high concentrations of plasma dopamine (42.0 +/- 14.6 ng/ml) and norepinephrine (45.7 +/- 8.4 ng/ml). However, the norepinephrine content of several peripheral tissues of these rats did not differ from those of the New England Deaconess ...
Louie G L - - 1986
We investigated the effect of aminophylline on thiopental sleep-times and monoamine neurotransmitter turnover rates in discrete brain areas. Aminophylline-treated rats had shorter thiopental sleep-times than saline-treated controls. Noradrenergic neurotransmission was greater following aminophylline treatment in thiopental-anesthetized rats in all brain areas while turnover in other monoaminergic pathways was unchanged. These ...
Bräutigam M - - 1986
It was reported that R(-)apomorphine and other catechols are potent inhibitors of dihydropteridine reductase in vitro. It was suggested that decreased levels of tetrahydrobiopterin may represent a mechanism by which R(-)apomorphine inhibits catecholamine synthesis in vivo. This paper demonstrates that tetrahydrobiopterin levels are not affected either in vitro (PC12 cells) ...
Danpure C J - - 1986
The subcellular distribution of 2-oxoglutarate:glyoxylate carboligase was investigated in a normal human liver, a liver from a patient with pyridoxine-resistant primary hyperoxaluria type I and rat livers subjected to various degrees and types of trauma. On continuous sucrose gradients most of the carboligase fractionated with a peak equilibrium density of ...
Erinoff L - - 1986
Rats were treated as neonates or adults with desmethylimipramine (DMI) followed by intraventricular 6-hydroxydopamine (6-HDA) or 5,7 dihydroxytryptamine (5,7-DHT). Locomotor activity of treated rats was measured in photocell cages. Neonatal treatment with 5,7-DHT produced hypoactivity during development while neonatal 6-HDA led to hyperactivity. Treatment of adult rats with 5,7-DHT or ...
Watanabe H - - 1986
Neuronal cell suspensions were implanted into the striatum of female rats that showed apomorphine-induced rotation and a reduction in striatal dopamine after intranigral treatment with 6-hydroxydopamine. The apomorphine-induced rotation was significantly suppressed by the transplantation in 12 out of 64 rats. DOPA accumulation and dopamine level (6.3 and 3.4%, respectively, ...
Ruggeri P - - 1986
Pyrroline formation in rat brain was studied in presence of different inhibitors of AldDH, AldR, ADH and MAO. The inhibition of AldDH and AldR, but not of ADH and MAO significantly increased DAO activity. The results indicate that the use of appropriate aldehyde metabolizing enzymes inhibitors allows to better understand ...
Raghavan K G - - 1986
Accumulation of oxalate leads to hyperoxaluria and calcium oxalate nephrolithiasis in man. Since oxalate is a metabolic end product in mammals, the feasibility of its enzymic degradation has been tested in vivo in rats by administering exogenous oxalate oxidase. Oxalate oxidase, isolated from banana fruit peels, in its native form ...
Grohmann M - - 1986
The neuronal and extraneuronal disposition of 3H-7,8- and 3H-7-labelled (-)-noradrenaline and dopamine was compared in in vitro studies. In agreement with earlier studies, the present results show that the presence of a tritium label in position 8 (i.e., on the alpha-carbon) has two consequences: a) the rate of deamination declines ...
O'Carroll A M - - 1986
The selective monoamine oxidase inhibitors clorgyline and (?)-deprenyl were used to study the distribution of monoamine oxidase-A and -B (MAO-A, MAO-B) activities towards (?)-noradrenaline and (+),(?)-adrenaline in homogenates from seven different regions of human brain. The activities towards 5-hydroxytryptamine and 2-phenethylamine, which are essentially specific substrates for the A- and ...
Pommier G J - - 1986
This paper characterizes the molecular nature of the factors present in cytosol from F-344 rat McFiFi2(s) fibrosarcoma cells (FiCF) which mediate inhibition of PHA-induced lymphoproliferative responses. These are polyamines (spermine/spermidine) conjugated to different protein carriers. Interaction of these complexes with polyamine oxidase (PAO) present in fetal calf or rat serum ...
Heikkila R E - - 1985
The 1-methyl-4-phenyl-pyridinium ion (MPP+) is the four electron oxidation product of the dopaminergic neurotoxin 1-methyl-4-phenyl-1,2,3,6 -tetrahydropyridine (MPTP). MPP+ can be formed by the oxidation of MPTP by monoamine oxidase B to the intermediate dihydropyridinium species, MPDP+, which is spontaneously transformed to MPP+. In the present study, MPP+, like the mitochondrial ...
Yoshida T - - 1985
During the early stages of the carcinogen 2-acetylaminofluorene (2-AAF) feeding, there were marked decreases of hepatic mitochondrial type B monoamine oxidase (MAO) and kynurenine 3-hydroxylase activities in male rats, but not in female rats. The administration of N-hydroxy-2-AAF (N-OH-2-AAF), a proximate carcinogenic metabolite of 2-AAF, to male rats also resulted ...
Zebrowska-Lupina I - - 1985
The influence of antidepressants: nomifensine, imipramine, amitriptyline and trazodone on the effect of antiparkinsonian agents: trihexyphenidil and L-DOPA + carbidopa mixture (sinemet) in the model of haloperidol catalepsy was investigated in rats. In some experiments deprenyl, a selective MAO-B inhibitor, was used. It was found that antidepressant drugs in doses ...
Sparks D L - - 1985
We previously reported that 6-methoxy-1,2,3,4-tetrahydro-beta-carboline (6-MeO-THBC) attenuated audiogenic seizures (AGS) in 21-day-old DBA/2J mice and also inhibited brain monoamine oxidase-A (MAO-A) and serotonin (5-hydroxytryptamine, 5-HT) uptake leading to increased brain 5-HT concentration. In this study, the sensitivity of AGS to 5-HT manipulation was evaluated by utilizing drug combinations which paralleled ...
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