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The effect of the MAO-A selective inhibitor brofaromine on the plasma and urine concentrations of some biogenic amines and their acidic metabolites in bulimia nervosa.

1. Brofaromine or placebo were administered to female bulimia nervosa patients over a period of eight weeks. Plasma and urinary trace amines, their acidic metabolites and the acidic metabolites of the catecholamines and serotonin were assessed prior to treatment and at four and eight weeks after commencement of treatment. 2. The levels of both plasma and urinary homovanillic and vanilmandelic acids declined significantly during the first four weeks of treatment with brofaromine and then partially recovered to pre-drug levels by the eighth week. 5-Hydroxyindoleacetic acid levels were not affected by drug treatment at the times assessments were made. Urinary tryptamine increased significantly during the first four weeks of brofaromine treatment then partially recovered towards pre-drug levels by the eighth week. No effect from placebo treatment was observed.

Biogenic Amines↗

Electrophysiological evidence for the existence of separate receptor mechanisms mediating the action of 5-hydroxytryptamine.

The transepithelial potential recorded across the salivary gland of the blowfly Calliphora responded to 5-hydroxytryptamine (5-HT) with a complex depolarising response characterised by oscillatory activity at low doses. A rapid screening procedure for characterizing the electrophysiological response of the gland to 5-HT and its analogues was developed. It consisted of recording the potential during the gradual addition of the agent in the form of a ramp. 5-HT gave a characteristic electrophysiological signature which was then compared with that of other analogues. Tryptamine, bufotenine and dimethyltryptamine gave potential signatures very similar to those of 5-HT. Histamine, 4- and 5-fluoro-alpha-methyltryptamine gave s predominantly hyperpolarising response which is characteristic of the effect produced by cyclic AMP. Analogues with substituents at the 5-position (methyl, methoxy, chloro) and 4-hydroxytryptamine gave a depolarising response indicative of a predominantly calcium effect. It is concluded that 5-HT acts through separate transducing mechanisms. The depolarizing response seems to indicate an action through calcium whereas the hyperpolarizing response might be mediated through cyclic AMP. Whether or not these separate responses are linked to different 5-HT receptors remains to be determined.

Animals↗

Thermal sensitivity and effect of temperature acclimation on ocular serotonin N-acetyltransferase activity in Rana perezi.

The thermal sensitivity and the response to thermal acclimation of the serotonin N-acetyltransferase (NAT) activity in frog ocular tissue were studied. The ocular NAT shows a positive thermal modulation for both cosubstrates (tryptamine and acetyl-CoA). The higher NAT activity in the cold-acclimated group (4 degrees C) with respect to the warm-acclimated one (24 degrees C) implies a partial thermal compensation of the enzyme. The present results suggest that frog ocular NAT response to temperature entails a modulation of thermal sensitivity of the enzyme rather than changes in enzyme concentration.

Acclimatization↗

A proposed mechanism for the visions of dream sleep.

The visions of dream sleep are suggested to occur through a dream mechanism which implicates tryptamine derivatives as endogenous paychedelics. The hallucinations that occur in some schizophrenic syndromes are also proposed to occur through a similar, though desynchronized, mechanism. These compounds occur in the human pineal gland and are regarded as neurotransmitters or neuroregulators. A protocol for experimental verification is suggested.

Carbolines↗

Determination of tetrahydro-beta-carbolines in urine by high-performance liquid chromatography with suppression of artefact formation.

A high-performance liquid chromatographic method has been developed for the determination of urinary tetrahydro-beta-carbolines. When standing tryptamine with formaldehyde and acetaldehyde under extraction conditions, the significant amounts of artefact 1,2,3,4-tetrahydro-beta-carboline (TBC) and 1-methyl-1,2,3,4-tetrahydro-beta-carboline (MTBC) were formed in a short time. Urine samples added with 2-ethyl-1,2,3,4-tetrahydro-beta-carboline (an internal standard) were treated with fluorescamine, and then with glycine, followed by serial solvent extractions. Such a pretreatment using two-step reactions removed a precursor (trypamine) by extracting its fluorescamine derivative, and enhanced the detection response by consuming excess fluorescamine. It solved the analytical problem that artefact TBC and MTBC are formed during analysis. Reversed-phase ion-pair chromatography using a C8-column and trifluoroacetic acid as a counter ion completed a base-line separation of three analytes within 10 min. The calibration graphs showed a good linearity in the range 0.1-50.0 ng ml-1 of urine samples spiked with standard TBC and MTBC. In the spike experiment, the recovery and relative standard deviation were almost 100% and less than 3.0%, respectively, for both TBC and MTBC. The proposed method enables the determination of the genuine urinary concentrations of TBC and MTBC without involving their artefacts.

Acetaldehyde↗

The effect of the plant hormone indole-3-acetic acid and chemically related compounds on the growth of mouse fibroblast 3T3 cells.

1. The effect of the plant hormone indole-3-acetic acid (IAA) and the chemically related compounds: serotonin, tryptophan, I. pyruvic, I. butyric, I. propionic and tryptamine on the growth of 3T3 cells has been studied. 2. Each of these compounds increases the cell number in a variable degree. The increase is related to the presence of the serum in the medium. 3. The kinetic relation between IAA, foetal calf serum and cell growth was studied. 4. It may be that IAA and related compounds affect the cell growth through adenylate cyclase and cAMP-cGMP systems.

Animals↗

Problematical binding of [3H]5-hydroxytryptamine to rat gut myenteric membranes.

The binding of [3H]5-hydroxytryptamine (5-HT) to rat enteric membranes was inhibited by the inclusion of 5-HT 2-methyl-5-HT, 5-hydroxytryptophan, N,N,N-triethyltryptamine and 2-Br-N,N-diethyltryptamine in the incubation buffer. In contrast, tryptamine, 5-methoxytryptamine and 2-methyl-N,N-diethyltryptamine enhanced binding. Ascorbate and dithiothreitol facilitated and reduced binding at low and high concentrations respectively. Methysergide, tropisetron, paroxetine and pargyline failed to modify binding. However, following the establishment of [3H]5-HT binding, the subsequent addition of 5-HT and other agents failed to displace [3H]5-HT binding. Heat treatment of the membrane preparation also failed to modify [3H]5-HT binding. The latter findings of an irreversible and heat-insensitive binding indicate that the apparently high affinity 'specific' labelling of [3H]5-HT to rat enteric membranes does not represent receptor-bound [3H]5-HT. The complex interaction between [3H]5-HT and other agents may reflect oxidative events and problematic binding.

5-Methoxytryptamine↗

Exploitation of the unusual thermodynamic properties of human myeloperoxidase in inhibitor design.

Myeloperoxidase plays a fundamental role in oxidant production by neutrophils. It uses hydrogen peroxide and chloride to catalyze the production of hypochlorous acid (HOCl), which contributes to both bacterial killing and oxidative injury of host tissue. Thus, MPO is an interesting target for anti-inflammatory therapy. Here, based on the extraordinary and MPO-specific redox properties of its intermediates compound I and compound II, we present a rational approach in selection and design of reversible inhibitors of HOCl production mediated by MPO. In detail, indole and tryptamine derivatives were investigated for their ability to reduce compounds I and II and to affect the chlorinating activity of MPO. It is shown that these aromatic one-electron donors bound to the hydrophobic pocket at the distal heme cavity and were oxidized efficiently by compound I (k3), which has a one-electron reduction potential of 1.35 V. By contrast, compound II (E degrees ' of the compound II/ferric couple is 0.97 V) reduction (k4) was extremely slow. As a consequence compound II, which does not participate in the halogenation cycle, accumulated. The extent of chlorinating activity inhibition (IC50) was related to the k3/k4 ratio. The most efficient inhibitors were 5-fluorotryptamine and 5-chlorotryptamine with IC50 of 0.79 microM and 0.73 microM and k3/k4 ratios of 386,000 and 224,000, respectively. The reversible mechanism of inhibition is discussed with respect to the enzymology of MPO and the development of drugs against HOCl-dependent tissue damage.

Binding Sites↗

Analysis of hallucinogenic constituents in Amanita mushrooms circulated in Japan.

The constituents of seven mushrooms sold as Amanita muscaria or Amanita pantherina (five A. muscaria and two A. pantherina) and four "extracts purported to contain A. muscaria" products that are currently circulated in Japan were determined. All mushroom samples were identified as A. muscaria or A. pantherina by macroscopic and microscopic observation. The dissociative constituents, ibotenic acid (IBO) and muscimol (MUS), were extracted with 70% methanol twice and determined by gas chromatography/mass spectrometry. The IBO (as the hydrate)/MUS contents were in the range of <10-2845ppm/46-1052ppm in the cap of A. muscaria and 188-269ppm/1554-1880ppm in the cap of A. pantherina. In the caps, these compounds had a tendency to be more concentrated in the flesh than in the cuticle. On the other hand, the IBO/MUS contents in the stem were far lower than in the caps. In the "extracts purported to contain A. muscaria" products, IBO/MUS were detected below the lower limit of calibration curve (<10ppm/<25ppm) or not detected. However, these samples contained other psychoactive compounds, such as psychoactive tryptamines (5-methoxy-N,N-diisopropyltryptamine and 5-methoxy-N,N-dimethyltryptamine), reversible monoamine oxidase inhibitors (harmine and harmaline) and tropane alkaloids (atropine and scopolamine), which were not quantified. This is the first report of the chemical analysis of Amanita mushrooms that are circulated in the drug market.

Amanita↗

Simultaneous determination of nineteen hallucinogenic tryptamines/beta-calbolines and phenethylamines using gas chromatography-mass spectrometry and liquid chromatography-electrospray ionisation-mass spectrometry.

To investigate the trend of non-controlled drugs of abuse, simultaneous analytical methods were developed using GC-MS and LC-ESI-MS for 8 tryptamines/beta-carbolines, 6 phenethylamines of typically non-controlled substances in Japan, and, additionally, five legally controlled tryptamines and phenethylamines originally found in fungi or plants. Moreover, the proposed methods were applied to analyses of these drugs in 99 kinds of products (a total number of 123 products purchased at adult shops or via the Internet over the past 2 years in Japan), which potentially advertised psychotropic/psychoactive effects. The samples were extracted with methanol under ultrasonication. After centrifugation, the extracts were filtered prior to injections. GC-MS analysis was performed using a DB-5MS capillary column. Regarding the LC-ESI-MS analysis; the separation of the target drugs was optimized on an ODS column in acetonitrile/MeOH (7:3)-10 mM ammonium formate buffer (pH 3.5)/acetonitrile (95:5) by a linear gradient program and a quantitative analysis was carried out by the monitoring of each [M+H]+ in the positive ion mode of ESI-MS. As a result of the analyses using GC-MS and LC-ESI-MS, 5-MeO-DIPT (the synthetic substance known by the street name "Foxy") was found in 8 out of the 99 kinds of products. Additionally, AMT (from brown powder), DMT (from dried plant), harmine and harmaline (from dried plant) were also found in some of the 99 products. These analytical methods could be useful for the investigation of the distribution of the non-controlled psychotropic tryptamines/beta-carbolines and phenethylamines in the market.

Calibration↗

HPLC method for the determination of fluvoxamine in human plasma and urine for application to pharmacokinetic studies.

A simple, specific and sensitive high-performance liquid chromatographic (HPLC) method has been developed for the assay of fluvoxamine in human plasma and urine. The method was based on reaction of fluvoxamine with 1,2-naphthoquinone-4-sulphonic acid sodium salt (NQS) forming orange colored product. The fluvoxamine-NQ derivative was separated by isocratic reversed-phase HPLC and detected at 450 nm. The chromatographic conditions were as follows: Phenomenex C(18) (250 mm x 4.6 mm i.d., 5 microm) column, mobile phase consisting of acetonitrile/water (80:20 v/v) at a flow rate of 1 ml/min. Tryptamine was selected as an internal standard. The assay was linear over the concentration range of 5-145 and 2-100 ng/ml for plasma and urine, respectively. The limits of detection (LOD) were 1.4 and 1 ng/ml for plasma and urine estimation at a signal-to-noise (S/N) ratio of 3. The limits of quantification (LOQ) were 5 and 2 ng/ml for plasma and urine, respectively. The extraction recoveries were found to be 96.66+/-0.69 and 96.73+/-2.17% for plasma and urine, respectively. The intra-day and inter-day standard deviations (S.D.) were less than 1. The method indicated good performance in terms of specificity, linearity, detection and quantification limits, precision and accuracy. This assay was demonstrated to be applicable for clinical pharmacokinetic studies.

Chromatography, High Pressure Liquid↗

Combined intoxication with methylone and 5-MeO-MIPT.

Although preclinical studies suggest that methylone (2-methylamino-1-[3,4-methylenedioxyphenyl]propan-1-one) and 5-MeO-MIPT (5-methoxy-N-methyl,N-isopropyl tryptamine) may have psychostimulant properties, the scientific reports about the clinical effects of these agents are scant. We describe a 27-year-old male patient with substance intoxication after a single ingestion of the mixture of methylone and 5-MeO-MIPT. Though he bought the drug as pure methylone powder via an internet order, our chemical analyses indicated that the drug was composed of about 60% methylone (120 mg) and 38% 5-MeO-MIPT (76 mg). This case report suggests that clinicians should be alert to the possibility of the emergence of methylone or 5-MeO-MIPT intoxication, and substance-related mental disorder may be complicated by combined use of other psychoactive drugs.

Adult↗

The repertoire of trace amine G-protein-coupled receptors: large expansion in zebrafish.

Trace amines, such as tyramine, beta-phenylethylamine, tryptamine, and octopamine, are present in trace levels in nervous systems and bind a specific family of G-protein-coupled receptors (GPCR), but the function or origin of this system is not well understood. We searched the genomes of several eukaryotic species for receptors similar to the mammalian trace amine (TA) receptor subfamily. We identified 18 new receptors in rodents that are orthologous to the previously known TA-receptors. Remarkably, we found 57 receptors (and 40 pseudogenes) of this type in the zebrafish (Danio rerio), while fugu (Takifugu rubripes) had only eight receptors (and seven pseudogenes). We mapped 47 of the zebrafish TA-receptors on chromosomes using radiation hybrid panels and meiotic mapping. The results, together with the degree of conservation and phylogenetic relationships displayed among the zebrafish receptors suggest that the family arose through several different mechanisms involving tetraploidization, block duplications, and local duplication events. Interestingly, these vertebrate TA-receptors do not show a close evolutionary relationship to the invertebrate TA-binding receptors in fruitfly (Drosophila melanogaster), indicating that the ability to bind TA have evolved at least twice in animal evolution. We collected in total over 100 vertebrate TA-receptor sequences, and our phylogenetic analysis shows that several TA-receptors have evolved rapidly with remarkable species variation and that the common ancestor of vertebrate TA-receptors arose before the split of the ray-finned and lobe-finned fishes. The evolutionary history of the TA-receptors is more complex than for most other GPCR families and here we suggest a mechanism by which they may have arisen.

Amino Acid Sequence↗

Characterisation of 5-HT receptors in human coronary arteries by molecular and pharmacological techniques.

5-Hydroxytryptamine (5-HT) can produce both vasoconstrictor and vasorelaxant effects in human coronary arteries and the response to 5-HT can be influenced by the presence of disease. The aim of the present study was to elucidate the 5-HT receptor subtypes responsible for mediating 5-HT-evoked contraction of human coronary arteries using pharmacological, molecular and immunocytochemical approaches. Normal human coronary arteries, with intact endothelium, were mounted in tissue baths, and the vascular responses to 5-HT and 5-HT receptor agonists were studied. The effects of 5-HT1 and 5-HT2 receptor antagonists on these responses were also studied. Expression of messenger ribonucleic acid (mRNA) encoding different 5-HT receptors in human coronary arteries, atrium, ventricle wall and epicardium was determined using reverse transcriptase-polymerase chain reaction (RT-PCR) and Southern blot analysis. The expression of 5-HT1B or 5-HT1D receptor protein was studied using subtype selective antibodies and standard immunocytochemical techniques. The rank order of 5-HT receptor agonist potency in causing vasoconstriction was 5-carboxamido tryptamine, (5-CT) > zolmitriptan = BW183C91 (N10-desmethyl zolmitriptan) = alpha-methyl-5-hydroxytryptamine (alpha-CH3-5-HT) = 5-HT = sumatriptan > 2-methyl-5-hydroxytryptamine (2-CH3-5-HT) = 8-hydroxy-DPAT (8-OH-DPAT). Alpha-CH3-5-HT, 5-CT, 5-HT, zolmitriptan and BW 183C91 were significantly more potent (approximately 3-fold) than sumatriptan and 2-CH3-5-HT, which in turn were more potent than 8-OH-DPAT. Ketanserin and methiothepin (5-HT2 and 5-HT1 receptor antagonists, respectively) caused parallel rightward shifts of the concentration-effect curves to alpha-CH3-5-HT or 5-CT, respectively, without changing the maximum contractile response. In human coronary arteries, atrium. ventricle and epicardium. RT-PCR products corresponding to the human 5-HT2A, 5-HT1B and 5-HT1F receptors were expressed in high levels, mRNAs coding for 5-HT7, 5-HT1A and 5-HT1D receptors were only weakly expressed. No 5-HT1F receptor mRNA was detected. In coronary arteries there was a differential expression of 5-HT1B versus 5-HT1D receptor mRNAs, with 5-HT1B mRNAs being found in greater abundance. Dense 5-HT1B-immunoreactivity was detected on smooth muscle layer within coronary artery, however, 5-HT1D-immunoreactivity was not detected. It is concluded that 5-HT-evoked contraction of human coronary arteries is most probably mediated via the activation of both 5-HT1B and 5-HT2A receptors.

8-Hydroxy-2-(di-n-propylamino)tetralin↗

Separation and quantitation of some urinary arylalkylamines.

The arylalkylamines m- and p-tyramine, beta-phenylethylamine and tryptamine in their unconjugated forms have been identified and quantitated in urine collected from human volunteers. Their excretion levels (mean+/-standard error of the mean in mug/g creatinine) were, respectively, 67 +/- 5, 419 +/- 37, 4.6 +/- 1.2, and 82 +/- 11.

Chromatography, Ion Exchange↗

Quantitation of tryptophan metabolites in rat feces by thin-layer chromatography.

Indole, skatole, indole-3-acetic acid, indole-3-propionic acid, tryptamine, and free tryptophan have been extracted from rat fecal samples and quantitated by thin-layer chromatography. Additional tryptophan metabolites have been recovered in yields of 87-97% from supplemented fecal samples. Detection limits for all the compounds studied were in the 0.1 mug/g feces range. Quantitation was possible in the mug/g range with an estimated accuracy of plus or minus 10%.

Animals↗

Two chromone-secoiridoid glycosides and three indole alkaloid glycosides from Neonauclea sessilifolia.

From the dried roots of Neonauclea sessilifolia, two new chromone-secoiridoid glycosides, sessilifoside and 7"-O-beta-D-glucopyranosylsessilifoside, and three novel indole alkaloid glycosides, neonaucleosides A, B, and C, were isolated along with the main known glycosides, 5-hydroxy-2-methylchromone-7-O-beta-D-apiofuranosyl-(1-->6)-beta-D-glucopyranoside, sweroside, loganin, grandifloroside, and quinovic acid 3 beta-O-beta-D-quinovopyranoside-28-O-beta-D-glucopyranoside. The structures of these new glycosides were determined by spectroscopic and chemical means. Neonaucleoside A and its C-3 epimer were prepared from secologanin and tryptamine.

Glycosides↗