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Paul Pevet - One of the best experts on this subject based on the ideXlab platform.
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low ambient temperature does not affect the pineal concentrations of either 5 Methoxytryptamine or melatonin in golden hamsters kept under short photoperiod
Journal of Pineal Research, 1991Co-Authors: Florence I Raynaud, Paul PevetAbstract:This work investigates the rhythmic synthesis of pineal 5-Methoxytryptamine and related indoles in golden hamsters as a function of ambient temperature. 5-Methoxytryptamine, 5-methoxytryptophol, 5-methoxyindole acetic acid, and melatonin were measured by high pressure liquid chromatography (HPLC) in the pineal gland of golden hamsters after inhibition of monoamine oxidase. In our experimental conditions, the pineal 5-methoxyindole concentrations of hamsters kept at 5 degrees C were similar to those observed at 20 degrees C. These results suggest that low temperature, which is known to accelerate the short photoperiod-induced gonadal regression, acts at a level different to that of the pineal gland or affects another compound in the pineal gland.
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5 Methoxytryptamine is metabolized by monoamine oxidase a in the pineal gland and plasma of golden hamsters
Neuroscience Letters, 1991Co-Authors: Florence I Raynaud, Paul PevetAbstract:Pineal concentrations of 5-Methoxytryptamine, 5-methoxytryptophol, 5-methoxyindole acetic acid and melatonin were determined using high performance liquid chromatography following administration of different monoamine oxidase (MAO) inhibitors (clorgyline, pargyline and deprenyl) to golden hamsters. Plasma concentrations of 5-Methoxytryptamine, 5-methoxytryptophol and melatonin were also measured following 5-Methoxytryptamine administration to hamsters pretreated with MAO inhibitors. A significant increase in pineal and plasma 5-Methoxytryptamine together with a decrease in 5-methoxytryptophol concentrations was observed after clorgyline or pargyline. In contrast, following deprenyl administration, no change in pineal and plasma 5-methoxyindoles was observed. These results indicate that monoamine oxidase A is responsible for oxidative deamination of 5-Methoxytryptamine.
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plasma concentrations of 5 Methoxytryptamine 5 methoxytryptophol and melatonin after 5 Methoxytryptamine administration of golden hamsters physiological implications
Journal of Neural Transmission, 1991Co-Authors: Florence I Raynaud, B Vivienroels, Mireille Massonpevet, Paul PevetAbstract:5-Methoxytryptamine (5-MT), 5-methoxytryptophol (5-ML) and melatonin (Mel) were measured in the plasma after 2, 5, and 8 weeks administration of 25 micrograms 5-MT to golden hamsters kept under long photoperiod. 5-MT showed a one compartment kinetic profile in the plasma with half lives of 14.8 min after 2 weeks, 15 min after 5 weeks and 19.1 min after 8 weeks. A rapid metabolism of 5-MT was shown, Mel and 5-ML being detected in the plasma following 5-MT administration. However it was also shown that the gonadal atrophy observed after 5-MT administration cannot be due to its metabolism into these 2 compounds. Indeed when exogenously administered at a dose generating the same plasma concentration as that observed after 5-MT, the gonadal regression observed after the association of 5-ML and Mel is much less than that observed after 5-MT. 5-MT is thus a compound of great physiological interest.
Florence I Raynaud - One of the best experts on this subject based on the ideXlab platform.
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low ambient temperature does not affect the pineal concentrations of either 5 Methoxytryptamine or melatonin in golden hamsters kept under short photoperiod
Journal of Pineal Research, 1991Co-Authors: Florence I Raynaud, Paul PevetAbstract:This work investigates the rhythmic synthesis of pineal 5-Methoxytryptamine and related indoles in golden hamsters as a function of ambient temperature. 5-Methoxytryptamine, 5-methoxytryptophol, 5-methoxyindole acetic acid, and melatonin were measured by high pressure liquid chromatography (HPLC) in the pineal gland of golden hamsters after inhibition of monoamine oxidase. In our experimental conditions, the pineal 5-methoxyindole concentrations of hamsters kept at 5 degrees C were similar to those observed at 20 degrees C. These results suggest that low temperature, which is known to accelerate the short photoperiod-induced gonadal regression, acts at a level different to that of the pineal gland or affects another compound in the pineal gland.
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5 Methoxytryptamine is metabolized by monoamine oxidase a in the pineal gland and plasma of golden hamsters
Neuroscience Letters, 1991Co-Authors: Florence I Raynaud, Paul PevetAbstract:Pineal concentrations of 5-Methoxytryptamine, 5-methoxytryptophol, 5-methoxyindole acetic acid and melatonin were determined using high performance liquid chromatography following administration of different monoamine oxidase (MAO) inhibitors (clorgyline, pargyline and deprenyl) to golden hamsters. Plasma concentrations of 5-Methoxytryptamine, 5-methoxytryptophol and melatonin were also measured following 5-Methoxytryptamine administration to hamsters pretreated with MAO inhibitors. A significant increase in pineal and plasma 5-Methoxytryptamine together with a decrease in 5-methoxytryptophol concentrations was observed after clorgyline or pargyline. In contrast, following deprenyl administration, no change in pineal and plasma 5-methoxyindoles was observed. These results indicate that monoamine oxidase A is responsible for oxidative deamination of 5-Methoxytryptamine.
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plasma concentrations of 5 Methoxytryptamine 5 methoxytryptophol and melatonin after 5 Methoxytryptamine administration of golden hamsters physiological implications
Journal of Neural Transmission, 1991Co-Authors: Florence I Raynaud, B Vivienroels, Mireille Massonpevet, Paul PevetAbstract:5-Methoxytryptamine (5-MT), 5-methoxytryptophol (5-ML) and melatonin (Mel) were measured in the plasma after 2, 5, and 8 weeks administration of 25 micrograms 5-MT to golden hamsters kept under long photoperiod. 5-MT showed a one compartment kinetic profile in the plasma with half lives of 14.8 min after 2 weeks, 15 min after 5 weeks and 19.1 min after 8 weeks. A rapid metabolism of 5-MT was shown, Mel and 5-ML being detected in the plasma following 5-MT administration. However it was also shown that the gonadal atrophy observed after 5-MT administration cannot be due to its metabolism into these 2 compounds. Indeed when exogenously administered at a dose generating the same plasma concentration as that observed after 5-MT, the gonadal regression observed after the association of 5-ML and Mel is much less than that observed after 5-MT. 5-MT is thus a compound of great physiological interest.
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effect of different photoperiods on the diurnal rhythm of 5 Methoxytryptamine in the pineal gland of golden hamsters mesocricetus auratus
Journal of Neural Transmission, 1991Co-Authors: Florence I Raynaud, P PevetAbstract:This study tested the photo-dependency of the rhythmic synthesis of 5-Methoxytryptamine (5-MT) in the pineal gland of golden hamsters. After pargyline administration, pineal 5-Methoxytryptamine and melatonin were measured by HPLC in male golden hamsters kept under short and long photoperiod. In both photoperiodic regimes, a clear 5-MT rhythm was observed which fitted a sinusoidal function with high values occuring during the day-time and low values occuring during the night-time. The duration of the low nighttime levels was clearly proportional to the length of the dark phase. A marked rhythm of melatonin synthesis was also seen with low daytime levels and high night-time values. An inverse relationship between 5-MT and melatonin levels was observed. Thus, after pargyline administration, the rhythms of 5-MT and melatonin in the pineal gland of golden hamsters are photoperiod-dependent and show a reciprocal relationship.
C W Tsang - One of the best experts on this subject based on the ideXlab platform.
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retinal 5 Methoxytryptamine and 5 methoxyindole 3 acetic acid in the rat and quail diurnal rhythms and interspecies differences
Biochemical and Biophysical Research Communications, 1997Co-Authors: S F Pang, C W TsangAbstract:Endogenous 5-Methoxytryptamine (5MT) and its biosynthetic oxidation product, 5-methoxyindole-3-acetic acid (5MIAA), were successfully identified and measured in the retina of the rat and quail by gas chromatography/electron-capture negative ion chemical ionization mass spectrometry (GC/EC-NICI-MS). In the rat retina, diurnal rhythms of 5MT and 5MIAA, with high levels at mid-light and opposite to that of melatonin, were observed. In the quail, high levels of retinal 5MT and 5MIAA were found at mid-dark, and in phase to that of melatonin. Biosynthetic pathways for retinal 5MT and 5MIAA in the rat and quail were discussed in relation to the diurnal rhythms observed. Our results indicate that the biosynthesis and physiological functions of retinal 5MT and 5MIAA could be species dependent.
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analysis of 5 Methoxytryptamine at the femtomole level in the rat and quail brain by gas chromatography electron capture negative ion chemical ionization mass spectrometry
Journal of Chromatography B: Biomedical Sciences and Applications, 1996Co-Authors: C W Tsang, C L Chan, S F PangAbstract:Abstract A sensitive method for the measurement of endogenous 5-Methoxytryptamine in brain tissue has been developed using capillary column gas chromatography-electron-capture negative-ion chemical ionization mass spectrometry. 5-Methoxytryptamine was first converted to N-[2H3]acetyl-5-Methoxytryptamine by reaction with hexa-deuterated acetic anhydride, followed by reaction with pentafluoropropionic anhydride to yield the highly electron-capturing 3,3′-spirocyclic pentafluoropropionyl indolenine derivative. Quantitative analysis was carried out by selected-ion monitoring of the [M-HF] and [M-HF-DF] ion intensity of the 3,3′-spirocyclic pentafluoropropionyl indolenine derivative, using 5-methoxy-[α,α,β,β-2H4]tryptamine as the internal standard. The presence of 5-Methoxytryptamine in the brain tissue was demonstrated. In the absence of a monoamine oxidase inhibitor, the mean±S.D. levels of 5-Methoxytryptamine in the rat and quail whole brain were found to be 30±6 and 347±52 pg/g, respectively. The possible physiological functions of 5-Methoxytryptamine as a neuromodulator and/or neurotransmitter have to be considered.
S F Pang - One of the best experts on this subject based on the ideXlab platform.
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retinal 5 Methoxytryptamine and 5 methoxyindole 3 acetic acid in the rat and quail diurnal rhythms and interspecies differences
Biochemical and Biophysical Research Communications, 1997Co-Authors: S F Pang, C W TsangAbstract:Endogenous 5-Methoxytryptamine (5MT) and its biosynthetic oxidation product, 5-methoxyindole-3-acetic acid (5MIAA), were successfully identified and measured in the retina of the rat and quail by gas chromatography/electron-capture negative ion chemical ionization mass spectrometry (GC/EC-NICI-MS). In the rat retina, diurnal rhythms of 5MT and 5MIAA, with high levels at mid-light and opposite to that of melatonin, were observed. In the quail, high levels of retinal 5MT and 5MIAA were found at mid-dark, and in phase to that of melatonin. Biosynthetic pathways for retinal 5MT and 5MIAA in the rat and quail were discussed in relation to the diurnal rhythms observed. Our results indicate that the biosynthesis and physiological functions of retinal 5MT and 5MIAA could be species dependent.
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identification and diurnal studies of pineal and serum 5 Methoxytryptamine in the rat and quail
Neuroscience Letters, 1997Co-Authors: S F Pang, Chileung Chan, Chunwai TsangAbstract:Picomole to femtomole per gland/ml levels of 5-Methoxytryptamine (5MT) in the pineal gland and serum of the rat and quail were determined, in the absence of a monoamine oxidase inhibitor, by using the ultra-sensitive technique of capillary column gas chromatography/electron-capture negative ion chemical ionization mass spectrometry. Diurnal rhythms of pineal 5MT with high levels at mid-light and low levels at mid-dark were found in both species, while serum 5MT levels showed less or no diurnal variations. The definitive presence of 5MT in the pineal gland and blood circulation provides further evidence that it is potentially a neurohormone. Whether 5MT is implicated in the photoperiodic responses and/or other physiological functions of animals, however, remains to be investigated.
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analysis of 5 Methoxytryptamine at the femtomole level in the rat and quail brain by gas chromatography electron capture negative ion chemical ionization mass spectrometry
Journal of Chromatography B: Biomedical Sciences and Applications, 1996Co-Authors: C W Tsang, C L Chan, S F PangAbstract:Abstract A sensitive method for the measurement of endogenous 5-Methoxytryptamine in brain tissue has been developed using capillary column gas chromatography-electron-capture negative-ion chemical ionization mass spectrometry. 5-Methoxytryptamine was first converted to N-[2H3]acetyl-5-Methoxytryptamine by reaction with hexa-deuterated acetic anhydride, followed by reaction with pentafluoropropionic anhydride to yield the highly electron-capturing 3,3′-spirocyclic pentafluoropropionyl indolenine derivative. Quantitative analysis was carried out by selected-ion monitoring of the [M-HF] and [M-HF-DF] ion intensity of the 3,3′-spirocyclic pentafluoropropionyl indolenine derivative, using 5-methoxy-[α,α,β,β-2H4]tryptamine as the internal standard. The presence of 5-Methoxytryptamine in the brain tissue was demonstrated. In the absence of a monoamine oxidase inhibitor, the mean±S.D. levels of 5-Methoxytryptamine in the rat and quail whole brain were found to be 30±6 and 347±52 pg/g, respectively. The possible physiological functions of 5-Methoxytryptamine as a neuromodulator and/or neurotransmitter have to be considered.
Russel J Reiter - One of the best experts on this subject based on the ideXlab platform.
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On the significance of an alternate pathway of melatonin synthesis via 5-Methoxytryptamine: comparisons across species.
Journal of Pineal Research, 2016Co-Authors: Rüdiger Hardeland, Moisés Alejandro Alatorre-jiménez, Kyoungwhan Back, Lucien C Manchester, Russel J ReiterAbstract:Melatonin is a phylogenetically ancient molecule. It is ubiquitously present in almost all organisms from primitive photosynthetic bacteria to humans. Its original primary function is presumable to be that of an antioxidant with other functions of this molecule having been acquired during evolution. The synthetic pathway of melatonin in vertebrates has been extensively studied. It is common knowledge that serotonin is acetylated to form N-acetylserotonin by arylalkylamine N-acetyltransferase (AANAT) or arylamine N-acetyltransferase (SNAT or NAT) and N-acetylserotonin is, subsequently, methylated to melatonin by N-acetylserotonin O-methyltransferase (ASMT; also known as hydroxyindole-O-methyltransferase, HIOMT). This is referred to as a classic melatonin synthetic pathway. Based on new evidence, we feel that this classic melatonin pathway is not generally the prevailing route of melatonin production. An alternate pathway is known to exist, in which serotonin is first O-methylated to 5-Methoxytryptamine (5-MT) and, thereafter, 5-MT is N-acetylated to melatonin. Here, we hypothesize that the alternate melatonin synthetic pathway may be more important in certain organisms and under certain conditions. Evidence strongly supports that this alternate pathway prevails in some plants, bacteria, and, perhaps, yeast and may also occur in animals.
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pharmacological aspects of n acetyl 5 Methoxytryptamine melatonin and 6 methoxy 1 2 3 4 tetrahydro β carboline pinoline as antioxidants reduction of oxidative damage in brain region homogenates
Journal of Pineal Research, 1999Co-Authors: Gitte Pless, Tina J P Frederiksen, Joaquin J Garcia, Russel J ReiterAbstract:Oxygen consumption is a necessity for all aerobic organisms, but oxygen is also a toxic molecule that leads to the generation of free radicals. The brain consumes a high percentage of the oxygen inhaled (18.5%), and it contains large amounts of unsaturated fatty acids, which makes it highly susceptible to lipid peroxidation. Melatonin (N-acetyl-5-Methoxytryptamine), the main secretory product of the pineal gland, is a free radical scavenger that was found to protect against lipid peroxidation in many experimental models. Another compound found in the pineal gland is pinoline (6-methoxy-1,2,3,4-tetrahydro-beta-carboline). Pinoline is structurally related to melatonin. Evidence suggests that pinoline may have an antioxidant capacity similar to that of melatonin. In this study, the ability of pinoline to protect against H2O2-induced lipid peroxidation of different rat brain homogenates (frontal cortex, striatum, cerebellum, hippocampus, and hypothalamus) was investigated. The degree of lipid peroxidation was assessed by estimating the levels of thiobarbituric acid reactive substances, malondialdehyde (MDA) and 4-hydroxyalkenals (4-HDA). Pinoline's antioxidant capacity was compared with that of melatonin. Both melatonin and pinoline reduced the level of MDA and 4-HDA in a dose-dependent manner in all brain regions tested. To compare the antioxidant capacities, percent-inhibition curves were created, and the IC50 values were calculated. The IC50 values for melatonin were higher in all brain regions than were those for pinoline. The IC50 values for melatonin in the five different brain regions ranged from 0.16 mM-0.66 mM, and for pinoline, they ranged from 0.04 mM-0.13 mM. The possibility of synergistic interactions between melatonin and pinoline were also determined using the method of Berenbaum. Little evidence for either synergistic, additive, or antagonistic interactions between melatonin and pinoline was found.
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the significance of the metabolism of the neurohormone melatonin antioxidative protection and formation of bioactive substances
Neuroscience & Biobehavioral Reviews, 1993Co-Authors: R Hardeland, Russel J Reiter, Burkhard Poeggeler, D X TanAbstract:Recent findings suggest that the ability of melatonin to enter all body tissues and to be metabolized, enzymatically or nonenzymatically, in any of them results in a spectrum of effects, which exceed substantially those transduced by membrane receptors. These actions comprise the formation of various bioactive compounds such as N-acetylserotonin, 5-Methoxytryptamine, N,N-dimethyl-5-Methoxytryptamine, 5-methoxytryptophol, cyclic 2-hydroxymelatonin, pinoline, and 5-methoxylated kynuramines. Apart from enzymatic metabolism, nonenzymatic reactions with free radicals, in particular the superoxide anion and the hydroxyl radical, represent a new and significant aspect of melatonin's biological role. Melatonin represents the most potent physiological scavenger of hydroxyl radicals found to date, and recent findings suggest an essential role of this indoleamine for protection from hydroxyl radical-induced carcinogenesis and neurodegeneration.
