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At least 847 records · Page 47Linked to original sources
PubMed1982

Effects of aldehyde dehydrogenase inhibitors on enzymes involved in the metabolism of biogenic aldehydes in rat liver and brain.

The effects of the aldehyde dehydrogenase inhibitors disulfiram, coprine and cyanamide on enzymes involved in the metabolism of biogenic aldehydes in rat liver and brain were studied. Both liver and brain aldehyde dehydrogenase activities were significantly decreased in rats pretreated with these drugs. In the liver, the low-Km aldehyde dehydrogenase activity was markedly decreased by all three drugs after 2 and 24 hr whereas only cyanamide inhibited the high-Km enzymes. The brain ALDH-activity with a low acetaldehyde concentration was significantly decreased by coprine and cyanamide at both times tested, whereas disulfiram caused no change after 2 hr but an inhibition of 38% after 24 hr. The brain ALDH-activity with a high acetaldehyde concentration was significantly decreased by coprine and cyanamide but not by disulfiram. The activity of the substrate specific enzyme succinate semialdehyde dehydrogenase in brain was slightly but significantly decreased in rats pretreated with cyanamide but not in rats pretreated with disulfiram or coprine. None of the drugs caused any changes in the activities of aldehyde reductase and monoamine oxidase in brains in vivo. The activity of monoamine oxidase in liver was significantly decreased by coprine after 24 hr. In contrast to the effects obtained in vivo, disulfiram was found to be an inhibitor in vitro of brain succinate semialdehyde dehydrogenase and liver monoamine oxidase. Aldehyde reductase was slightly inhibited by both disulfiram and 1-aminocyclopropanol in vitro.

Aldehyde Dehydrogenase↗
PubMed1987

Metabolism of biogenic aldehydes in isolated human blood cells, platelets and in plasma.

The metabolism of biogenic aldehydes was measured in different human blood fractions. Isolated erythrocytes, leukocytes, platelets and plasma were incubated with 3,4-dihydroxyphenyl-acetaldehyde (DOPAL) or 5-hydroxyindole-3-acetaldehyde (5-HIAL), the aldehydes derived from dopamine and 5-hydroxytryptamine, respectively. The disappearance of the aldehydes and the formation of acid and alcohol metabolites were analysed using high-performance liquid chromatography with electrochemical detection. The aldehydes were unstable in phosphate-buffered saline, but this nonenzymatic oxidation was prevented in the presence of EDTA, pyrophosphate or blood tissue. When DOPAL or 5-HIAL were incubated with erythrocytes, only acid metabolites were formed, whereas both acid and alcohol metabolites were formed in incubations with leukocytes or platelets. The amount of the acid metabolite exceeded that of the alcohol metabolite, both with leukocytes and platelets. No metabolites were formed when the aldehydes were incubated in plasma. The oxidation of the aldehydes in incubations with erythrocytes or platelets was totally inhibited in the presence of 50 microM of the aldehyde dehydrogenase inhibitor disulfiram. However, disulfiram did not inhibit the metabolism of DOPAL and 5-HIAL in incubations with leukocytes, suggesting that different isozymes of aldehyde dehydrogenase are present in leukocytes as compared to erythrocytes and platelets.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1982

Altered neuronal responsiveness to biogenic amines in rat cerebral cortex after serotonin denervation or depletion.

To further investigate monoaminergic mechanisms in cerebral cortex, responsiveness of cortical neurons to microiontophoretic applications of serotonin (5-HT), dopamine (DA) or noradrenaline (NA) was examined in the frontoparietal region of control, 5,7-dihydroxytryptamine (5,7-DHT)- and p-chlorophenylalanine (PCPA)-treated rats anesthetized with urethane. As a rule, 100 nA applications of either one of these biogenic amines induced marked slowing or total interruption of 'spontaneous' firing overlasting the 30 s period of ejection. Given the large amounts of monoamines ejected, it could be inferred that such microiontophoretic applications produced a maximal activation of receptors. In control rats, the responses to 5-HT, DA and NA were of approximately equal duration (approximately equal to 5 min). Two to 4 weeks after denervation with 5,7-DHT, most neurons (75%) exhibited greatly prolonged responses to 5-HT (approximately equal to 14 min), and marked depressions of firing could be induced by small ejection currents (approximately equal to 2 nA) having little or no effect in the controls. In addition, 85% of the units supersensitive to 5-HT showed considerably shortened responses to DA and NA (approximately equal to 1 min). After 2-14 days of depletion with PCPA, there was no change in the responsiveness to 5-HT in spite of a 91% lowering of cortical 5-HT content equivalent to that measured after denervation. Nevertheless, responsiveness to DA and NA was again diminished in a majority (80%) of the units tested. In control or PCPA-treated rats, acute administration of the 5-HT re-uptake blocker fluoxetine increased the duration of depressions induced by 100 nA applications of 5-HT but did not enhance responsiveness to low ejection currents. This suggested that, after 5-HT denervation, the suppression of re-uptake was mainly responsible for the prolongation of 5-HT responses ('presynaptic' component of supersensitivity), whereas a modification of 5-HT receptors accounted for the greater efficacy of small doses of 5-HT ('postsynaptic' component). Responsiveness to the microiontophoretic application of phenylephrine (PHE), a noradrenergic a-agonist, was comparable with that to NA in PCPA- and 5,7-DHT-treated as well as in control rats. Therefore, the hyposensitivity to DA and NA appeared indicative of a desensitization of catecholamine receptors caused by the absence of 5-HT. Such a desensitization may be viewed as an adaptive change resulting from an increased release of endogenous DA and NA. This interpretation would in turn imply that, normally, 5-HT regulates catecholamine release in the neocortex.

Afferent Pathways↗
PubMed1984

Biogenic amine-sensitive adenylate cyclases in primary culture of neuronal or glial cells from mesencephalon.

Primary cultures of virtually pure mesencephalic neurons (5 days) or glials (4 weeks) from 14-day-old mouse embryo were obtained using appropriate medium. Membranes prepared from neuronal cells contained mainly serotonin and beta 1-adrenergic-sensitive adenylate cyclases. However, a low but significant classical dopamine-sensitive adenylate cyclase activity (D1 receptor) was detected. Contrasting with the data obtained from a previous study on striatal neurons no adenosine-sensitive adenylate cyclase was found on mesencephalic neurons. Study on the additive effects of the 3 biogenic amines-sensitive adenylate cyclases indicated that: all neuronal cells having dopamine receptors possess beta 1-adrenergic receptors (no additivity); beta 1-adrenergic and serotonin receptors on the one hand, and dopamine and serotonin receptors on the other hand, were coupled with independent adenylate cyclase systems localized either on two different domains of the same cell or on different cells (complete additivity). Membranes prepared from primary mesencephalic cultures of glial cells contained a mixture of beta 1- and beta 2-adrenergic receptor subtypes coupled with an adenylate cyclase (70% and 30%, respectively). No dopamine- or serotonin-sensitive adenylate cyclase was detected on mesencephalic glial cells.

Adenylyl Cyclases↗
PubMed1987

A comparison of the effects of carbon monoxide intoxication and low-oxygen gas mixtures on cerebral biogenic amine metabolism.

The effects of 1% CO on cerebral biogenic amine metabolism was studied by measurement of cerebral hemisphere contents of 5-hydroxytryptophan (5-HTP), 5-hydroxytryptamine (5-HT), 5-hydroxyindoleacetic acid (5-HIAA), dihydroxyphenylalanine (DOPA) and dopamine (DA). The results indicated that 1% CO is associated with an increased cerebral hemisphere content of DA. In CO-exposed animals treated with the decarboxylase inhibitor, 3-hydroxybenzyl hydrazine, the rate of tryptophan hydroxylation was reduced. When the duration of exposure to a given range of arterial oxygen content was matched to that of a group exposed to a low-oxygen gas mixture (5% O2) the rates of tryptophan hydroxylation were equivalent. This suggests that at a given arterial total oxygen content the tissue oxygen tension and supply are equivalent in low O2 or CO hypoxia. Assessment of the effects of 1% CO on tyrosine hydroxylation indicated no significant effect on this enzyme step.

5-Hydroxytryptophan↗
PubMed1995

Molecular cloning and characterization of cDNA for insect biogenic peptide, growth-blocking peptide.

Growth-blocking peptide (GBP) is an insect biogenic peptide that prevents the onset of metamorphosis from larva to pupa. A cDNA coding for GBP is described. Mixed oligonucleotides derived from a GBP peptide sequence were used to generate amplified DNA by the polymerase chain reaction (PCR). Based on the sequence of the amplified DNA, a 41 bases oligonucleotide was designed for screening a cDNA library which was constructed from the armyworm Pseudaletia separata larvae parasitized with the parasitic wasp Cotesia kariyai. The cloned cDNA for GBP was 809 base pairs in length. An open reading frame of 429 base pairs encodes a pre-pro-peptide of 143 amino acid residues in which GBP is localized at the C-terminal region, and other three peptides including a putative signal peptide and appropriate processing sites for endoproteolytic cleavage precede the GBP sequence. Northern blot analyses demonstrate the presence of a 800-base mRNA transcript in fat body and 2.5-kilobase transcript in brain and nerve cord, suggesting the possibility that the transcription of GBP gene is regulated in a tissue-dependent manner. This interpretation was supported by isolating a GBP cDNA fragment from cDNA pool of brain-nerve cords. GBP mRNA is constantly expressed in both parasitized and non-parasitized last instar larvae and there is no difference in the levels of the mRNA between both larvae, thus indicating that parasitism may effect on translational or posttranslational level to elevate plasma GBP concentration.

Amino Acid Sequence↗
PubMed1992

Biogenic amines in the guinea pig endocrine pancreas.

Pancreata of guinea-pigs were investigated for the presence and cellular distribution of biogenic amines. Out of the established endocrine cell types only insulin (B-) cells contained immunoreactivity for serotonin and noradrenaline. However, the B-cells' content of both amines was quite variable. Serotonin was also confined to enterochromaffin (EC-) cells. No immunoreactivity for dopamine or histamine was present in any islet cell. Treatment of guinea-pigs with Ro-4-4602 led to a marked decrease of serotonin and noradrenaline in pancreatic endocrine cells. The present findings suggest that serotonin and noradrenaline are involved in the function of the endocrine pancreas, particularly of islet B-cells.

Animals↗
PubMed1995

Effect of crop development on biogenic emissions from plant populations grown in closed plant growth chambers.

The Biomass Production Chamber at John F. Kennedy Space Center is a closed plant growth chamber facility that can be used to monitor the level of biogenic emissions from large populations of plants throughout their entire growth cycle. The head space atmosphere of a 26-day-old lettuce (Lactuca sativa cv. Waldmann's Green) stand was repeatedly sampled and emissions identified and quantified using GC-mass spectrometry. Concentrations of dimethyl sulphide, carbon disulphide, alpha-pinene, furan and 2-methylfuran were not significantly different throughout the day; whereas, isoprene showed significant differences in concentration between samples collected in light and dark periods. Volatile organic compounds from the atmosphere of wheat (Triticum aestivum cv. Yecora Rojo) were analysed and quantified from planting to maturity. Volatile plant-derived compounds included 1-butanol, 2-ethyl-1-hexanol, nonanal, benzaldehyde, tetramethylurea, tetramethylthiourea, 2-methylfuran and 3-methylfuran. Concentrations of volatiles were determined during seedling establishment, vegetative growth, anthesis, grain fill and senescence and found to vary depending on the developmental stage. Atmospheric concentrations of benzaldehyde and nonanal were highest during anthesis, 2-methylfuran and 3-methylfuran concentrations were greatest during grain fill, and the concentration of the tetramethylurea peaked during senescence.

Biomass↗
PubMed1982

Use of a single compartment LCEC cell in the determinations of biogenic amine content and turnover.

Content and specific radioactivity of the biogenic monoamines and content of their precursors and metabolites were simultaneously determined in CNS tissue extracts with a high pressure liquid chromatography system (HPLC). The content of dopamine, norepinephrine, serotonin. 5-hydroxyindoleacetic acid, homovanillic acid, 3,4-dihydroxyphenylacetic acid and 4-hydroxy-3-methoxyphenylethyleneglycol and the turnover rate of dopamine, norepinephrine and serotonin were measured in discrete rat brain regions using a one compartment electrochemical detector cell coupled to a C18-reverse phase HPLC column. The small fluid volume dead space of the cell allows the direct and precise collection of individual peaks for determining specific radioactivities. This method is especially suitable for central nervous system tissue samples from 8-20 mg wet weight and the sensitivity of the system in its routine configuration is approximately 2 pmol. This method for determinations of turnover is appropriate for investigations of animals in sensitive behavioral paradigms.U

Animals↗
PubMed1987

Food intake and biogenic amine concentrations in brain regions of chicks following intracerebroventricular injection of six-hydroxydopamine.

The effect of catecholamine depletion within three brain regions on subsequent food intake and body weight gain were investigated in two week-old chicks. Two levels of pargyline (P; 50 mg/kg and 100 mg/kg intraperitoneally) and three levels of six-hydroxydopamine (6-OHDA; 0, 200 micrograms (136 free base) and 300 micrograms (204 free base) intracerebroventricularly) were administered to 36 chicks (n = 6 per treatment). The greatest reduction in food intake and body weight gain occurred in the group given 100 mg/kg P, 300 micrograms 6-OHDA. These chicks displayed an average aphagic response of 4.5 days. Chicks given the higher drug doses were hyperactive when handled and displayed difficulty in orienting their bills when attempting to consume pellets. Biogenic amines were determined in three brain regions (striatum, hypothalamus and brainstem) using high pressure liquid chromatography with electrochemical detection. Dopamine (DA) was reduced (p less than 0.05) in the striatum of all groups treated with 6-OHDA when compared to their respective controls. Significant depletions of norepinephrine (NE) occurred in all three brain regions in all groups treated with 6-OHDA when compared with their respective control groups (p less than 0.05). In contrast, striatal epinephrine levels were elevated in chicks given 100 mg P plus 6-OHDA. It is proposed that depletions of both DA and NE contribute to the aphagic or anorexic response of chicks following administration of the neurotoxin 6-OHDA.

Animals↗
PubMed1982

Modulation of nicotinic transmission by biogenic amines in bullfrog sympathetic ganglia.

Studies of transmission in isolated paravertebral sympathetic ganglia of the bullfrog and at the sciatic-sartarius muscle synapse in the frog yielded evidence that biogenic amines such as catecholamines or 5-hydroxytryptamine can modulate transmission in sympathetic ganglia and at the neuromyal junction. These two transmitter substances are able to modulate transmission by affecting the amount of ACh release from presynaptic terminals and also by affecting the sensitivity of nicotinic Ach receptors of the subsynaptic membrane. Information is presented as to how these compounds exert their modulatory effects on these synapses.

Acetylcholine↗
PubMed1983

Ontogeny of biogenic amines in respiratory nuclei of the rabbit brainstem.

The concentrations of the biogenic amines, norepinephrine, dopamine and serotonin, were determined in 5 respiratory-related brainstem regions by use of a micropunch technique and a sensitive enzymatic isotopic assay. Samples were taken from rabbits at different ages (term fetuses, 3, 7, 14, 21 days and 2-year-old adults). All brain regions contained norepinephrine, dopamine, and serotonin in measurable amounts, but the distribution was not uniform. Norepinephrine and dopamine remained relatively low (less than 5 ng/mg) in the fetus and during the first weeks of life. Norepinephrine achieved its highest levels in the nucleus tractus solitarius and the locus coeruleus of adult animals. Dopamine concentrations did not change significantly in any nuclear groups over the ages tested. Compared with the newborn values, high concentrations of serotonin were seen in all brainstem nuclei in the term fetus. Adult serotonin levels were not achieved during the neonatal period. These data demonstrate pre- and postnatal changes in neurotransmitter levels in brainstem nuclei which regulate respiratory control. The susceptibility of the newborn to abnormalities in respiratory control may be related to low serotonin levels observed during the postnatal period.

Animals↗
PubMed1993

Influence of synthetic and biogenic surfactants on the toxicity of water-soluble fractions of hydrocarbons in sea water determined with the bioluminescence inhibition test.

The influence of increasing amounts of surfactants on the toxicity of hydrocarbons was determined using the bioluminescence inhibition test (Microtox test). Three biogenic and three synthetic surfactants were tested against the water-soluble fractions (WSF) of crude and weathered Ekofisk oil, phenol, and naphthalene. Surfactant concentrations below 100 mg litre(-1) lowered the toxicity of the WSF, indicating an antagonistic interaction reducing the toxicities of surfactants and hydrocarbons. At concentrations greater than 100 mg litre(-1) the toxicity rose again and was higher than the untreated WSF. The point of reversal seemed to be the critical micelle concentration, at which the formation of oil/water emulsions is possible.

Journal Article↗
PubMed1992

Determination of carnosine and other biogenic imidazoles in equine plasma by isocratic reversed-phase ion-pair high-performance liquid chromatography.

The isocratic reversed-phase ion-pair high-performance liquid chromatographic technique presented provides a sensitive, rapid and reproducible analytical method for the selective determination of carnosine and other biogenic imidazoles in equine plasma. Plasma was deproteinized with 5-sulphosalicylic acid and the compounds of interest were isolated by sorbent extraction on Bond Elut PRS cartridges. Recoveries were 97-105% and the lowest limits of detection were 58.3-80.1 nM. All compounds of interest were well resolved within a maximum retention time of 9.2 min. The mean equine plasma carnosine level determined by this method was 11.31 microM. Comparative determinations were made in canine and human plasma. Carnosine was not detected in human plasma. Concentrations of imidazole in canine plasma are reported here for the first time.

Animals↗
PubMed2004

Biogenic capsules made of proteins and lipids.

Multilayer biogenic capsules with a micrometer scale were fabricated by self-assembly of proteins and lipids at the interface of emulsion droplets. The optical microscopy images demonstrate that spherical capsules at a fluid interface have uniform walls and the dried capsules possess a high mechanical strength. The hollow shells obtained provide a novel class of assembly with encapsulating drug molecules based on the layer-by-layer technique.

Adsorption↗
PubMed2004

The biogenic trace amine tyramine induces a pronounced hydroxyl radical production via a monoamine oxidase dependent mechanism: an in vivo microdialysis study in mouse striatum.

Tyramine is a biogenic trace amine that releases monoamines and is a good substrate for monoamine oxidase (MAO)-A/B. Here we investigated whether tyramine affects hydroxyl radical formation in the intact and lesioned dopaminergic system. Male C57bl/6 mice received systemic and local tyramine administrations. Hydroxyl radical formation and dopamine (DA) overflow were determined in the striatum using in vivo microdialysis in combination with the salicylate hydroxylation assay. Systemic injection of tyramine neither enhanced extracellular dopamine nor induced hydroxyl radical formation. In contrast, when tyramine was incorporated into the dialysate fluid, hydroxyl radical formation and extracellular dopamine levels were significantly enhanced. Systemic pretreatment with the MAO-A/B inhibitor tranylcypromine or with the dopaminergic neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) significantly diminished the tyramine-induced hydroxyl radical formation by 73.1% and 80.6%, respectively. We conclude that the mechanism of tyramine-induced hydroxyl free radical formation involves MAO metabolism and requires an intact dopaminergic system. Pharmacological intervention on the MAO-mediated formation of hydroxyl free radicals seems to be a promising strategy to prevent oxidative damage in the nigrostriatal dopaminergic system.

Animals↗
PubMed2004

On-column derivatization-capillary electrochromatography with o-phthalaldehyde/alkylthiol for assay of biogenic amines.

The elution behaviors of the biogenic amines, histamine (HA) and its metabolite methyl histamine (MHA), were evaluated by means of on-column derivatization (OCD)-capillary electrochromatography (CEC) which employed a monolithic octadecylsilica (ODS) capillary column (20 cm of effective length x 50 microm of inner diameter). Five kinds of alkylthiols, e.g., 2- hydroxyethylthiol (or 2-mercaptoethanol (2-ME)), ethanethiol (ET), 1-propanethiol (1-PT), 2-methyl-1-propanethiol (2-MPT) and 1-butanethiol (1-BT) were separately presented at 5 mM each in the OCD-CEC separation run buffer consisting of 60% acetonitrile in 5 mM o-phthalaldehyde (OPA)-10 mM borate buffer (pH 10). When 2-ME was present in the run buffer solution, both derivatives corresponding to HA and MHA migrated separately, but closely together through the capillary column. Replacement of 2-ME with 1-BT in the run buffer solution caused a delay in their elution profiles on the electrochromatogram and the separation between those two peaks became remarkably improved. The elution times of HA and MHA followed the increase in alkyl chain length or hydrophobicity of thiol, 1-BT > 2-MPT > 1-PT > ET > 2-ME. Performance of on-line preconcentrations of HA and MHA was also evaluated by varying the electrokinetic injection voltage from 1 kV to 8 kV. The peak area counts corresponding to HA recorded about 50 times higher when 2 kV was applied for 240 s to a 0.1 mM HA solution than when 8 kV was applied for 5 s. This method was next applied to a sample of human urine spiked with HA and MHA at levels of 0.1 microM each. Although HA and MHA peaks were not identifiable among the peaks corresponding to the materials in the urine matrix when OPA/2-ME was employed in a run buffer for the OCD-CEC, the separation and identification of their peaks became possible by replacing 2-ME with 1-BT in the run buffer solution.

Chromatography, Micellar Electrokinetic Capillary↗