LC-MS/MS quantitative determination of Tetrapterys mucronata alkaloids, a plant occasionally used in ayahuasca preparation.

INTRODUCTION: Tetrapterys mucronata Cav. (Malpighiaceae) is a plant used in some regions of Brazil in the preparation of ayahuasca. OBJECTIVE: To determine the content of the main tryptamine alkaloids in the stem bark of T. mucronata Cav. and assess their possible toxic and hallucinogenic properties based on the doses found in a water decoction that mimics the ayahuasca preparation. METHODS: Four alkaloids previously described for their toxic and hallucinogenic properties were quantitated by multiple reaction monitoring HPLC combined with electrospray ionisation and tandem MS (HPLC-ESI/MS/MS) in the water decoction and ethanolic extracts from the bark of T. mucronata. RESULTS: Exhaustive extraction of the stem barks with ethanol revealed the following alkaloid levels: bufotenine (1) 3.26 ± 0.31 mg/g, 5-methoxy-N-methyltryptamine (2) 0.88 ± 0.08 mg/g, 5-methoxy-bufotenine (3) 3.07 ± 0.22 mg/g and 2-methyl-6-methoxy-1,2,3,4-tetrahydro-ß-carboline (4) 0.14 ± 0.004 mg/g. The water decoction presented slightly lower levels, ranging between 2.32 ± 0.14, 0.50 ± 0.04, 1.53 ± 0.09 and 0.10 ± 0.01 mg/g for (1), (2), (3) and (4) respectively. CONCLUSIONS: The HPLC-ESI/MS/MS quantitation revealed significant alkaloid levels, in particular for bufotenine and 5-methoxy-bufotenine. As such compounds are known for their toxic and hallucinogenic properties, these results indicate that the consumption of this plant as an ingredient in ayahuasca preparations may present a risk to consumers.

Behavioral effects of α,α,ß,ß-tetradeutero-5-MeO-DMT in rats: comparison with 5-MeO-DMT administered in combination with a monoamine oxidase inhibitor.

RATIONALE: Ayahuasca is a psychoactive tea prepared from a combination of plants that contain a hallucinogenic tryptamine and monoamine oxidase inhibitors (MAOIs). Behavioral pattern monitor (BPM) experiments demonstrated that the combination of 5-methoxy-N,N-dimethyltryptamine (5-MeO-DMT) and a behaviorally inactive dose of an MAO(A) inhibitor such as harmaline or clorgyline induces biphasic effects on locomotor activity in rats, initially reducing locomotion and then increasing activity as time progresses. OBJECTIVES: The present study investigated whether the biphasic locomotor profile induced by the combination of 5-MeO-DMT and an MAOI is a consequence of a reduction in the rate of 5-MeO-DMT metabolism. This hypothesis was tested using a deuterated derivative of 5-MeO-DMT (α,α,ß,ß-tetradeutero-5-MeO-DMT) that is resistant to metabolism by MAO. RESULTS: Confirming our previous findings, 1.0 mg/kg 5-MeO-DMT (s.c.) had biphasic effects on locomotor activity in rats pretreated with a behaviorally inactive dose of the nonselective MAOI pargyline (10 mg/kg). Administration of 5-MeO-DMT alone, even at doses greater than 1.0 mg/kg, produced only reductions in locomotor activity. Although low doses of α,α,ß,ß-tetradeutero-5-MeO-DMT (0.3 and 1.0 mg/kg, s.c.) produced only hypoactivity in the BPM, a dose of 3.0 mg/kg induced a biphasic locomotor profile similar to that produced by the combination of 5-MeO-DMT and an MAOI. Receptor binding studies demonstrated that deuterium substitution had little effect on the affinity of 5-MeO-DMT for a wide variety of neurotransmitter binding sites. CONCLUSIONS: The finding with α,α,ß,ß-tetradeutero-5-MeO-DMT indicates that the hyperactivity induced by 5-MeO-DMT after MAO inhibition is a consequence of reduced metabolism of 5-MeO-DMT, leading to prolonged occupation of central serotonin receptors. These results demonstrate that deuterated tryptamines may be useful in behavioral and pharmacological studies to mimic the effects of tryptamine/MAOI combinations.

A new 5-hydroxy-indole derivative with preferential affinity for 5-HT1B binding sites.

The affinities of several 5-hydroxy-indole derivatives for serotonin-1 (5-HT1) binding site subtypes, labeled with 2 nM [3H]5-HT, were assessed by quantitative autoradiography on rat brain sections. The results obtained with known ligands, namely 5-hydroxytryptamine (5-HT), 5-methoxytryptamine (5-Me-OT), 5-methoxy-N,N- dimethyl-tryptamine (5-Me-ODMT), 5-hydroxy-N,N-dimethyl-tryptamine (bufotenine) and 8-hydroxy-2-[di-N-propylamino]tetralin (8-OH-DPAT) demonstrate the reliability and the advantages of this technique for pharmacological studies. Novel serotonin derivatives were synthesized by carboxymethylation of the hydroxyl group. One of those new ligands, serotonin-O-carboxy-methyl- glycyl-tyrosinamide (S-CM-GTNH2), inhibited 2 nM [3H]5-HT binding to the substantia nigra with an IC50 of 22.4 nM, a value which is 22 times lower than that found in the dentate gyrus and choroid plexus. This demonstrates the preferential affinity of S-CM-GTNH2 for 5-HT1B versus 5-HT1A and 5-HT1C binding sites. S-CM-GTNH2 contains a tyrosine residue, which may be useful for the synthesis of a radioactive iodinated molecule and for the preparation of 'long-lasting ligands' linked through peptide bonds with a protein. These derivatives could be of great interest for ultrastructural and behavioral studies relevant to 5-HT1B sites.

[Identification of N,N-dimethyl-O-(beta-D-glucopyranuronosyl)-5- hydroxytryptamine as a bufotenine metabolite in the rabbit]. / Identifikatsiia N,N-dimetil-O-(beta-D-gliukopiranuronozil)-5- oksitriptamina kak metabolita bufotenina v organizme krolikov.

A bufotenine metabolite has been isolated from the rabbit urine by the column chromatography on cellulose and preparative paper electrophoresis in acidic buffer. It has the structure of N,N-dimethyl-O-(beta-D-glucopyranuronosyl)-5-hydroxytryptamine as proved by comparison of chromatographic, electrophoretic and NMR data with those for respective synthetic O-glucuronide.

A comparison of cinobufotenine (the quaternary derivative of 5-HT) and some related compounds with coryneine (the quaternary derivative of dopamine) on the frog rectus, guinea-pig ileum and rat fundus strip preparations.

1 Coryneine is 2.7 times as active as cinobufotenine on the frog rectus but on the guinea-pig ileum cinobufotenine is 1.5 times as active as coryneine. Cinobufotenine is a potent stimulant of parasympathetic ganglia and its effect are competitively antagonized by hexamethonium. 2 The effects of pH on activity relative to a standard whose ionisation is constant (Me4+N or the trimethylammonium analogue of tryptamine) are consistent with the phenate form being weaker than the phenolic form but the changes are smaller than with coryneine because cinobufotenine is a weaker acid. 3 The hydroxyl group makes a large contribution to activity. Cinobufotenine is 9 times as active as the analogue without a hydroxyl on the frog rectus and 12 times as active as it on the ileum. The 5-methoxy analogue is an antagonist on the frog rectus and a very weak partial agonist on the ileum. 4 Cinobufotenine and the quaternary derivative of tryptamine have less than one-thousandth of the activity of 5-hydroxytryptamine on the rat fundus strip.

Bufotenine esters.

Bufotenine (5-hydroxy-N,N-dimethyltryptamine) has been reported to be behaviorally inactive or only very weakly active in man and animals; this may be a consequence of its low partition coefficient and resultant inability to penetrate the blood--brain barrier. The acetyl, propionyl, butyryl, isobutyryl, and pivalyl esters of bufotenine were prepared for future pharmacological evaluation. Unexpectedly, it was found that these esters all possess a relatively high affinity for the serotonin receptors of the isolated rat stomach fundus preparation. A semiquantitative chromatographic measurement of ester hydrolysis suggests that extensive hydrolysis of the esters to bufotenine does not occur under the conditions of the affinity assay.

Carbon 11 labeling of the psychoactive drug o-methyl-bufotenine and its distribution in the animal organism.

A methylated derivative of serotonin, O-methyl-bufotenine has been labeled with 11C on the two methyl groups of the amine function. In order to avoid the cyclization which occurs during the Eschweiler-Clarke synthesis, we adopted a milder methylation procedure, based on Borch's method using [11C]formaldehyde and sodium cyanoborohydride. Several tens of millicuries of injectable product could be obtained in 50 min in a perfectly pure state and having a specific radioactivity of 50 to 100 mCi/mumol. The distribution study of O-methyl-bufotenine in the mouse and rabbit showed an accumulation of significant quantities of the compound in the brain, kidneys, lungs and liver. The study of the rapid kinetics of this hallucinogenic molecule is compatible with labeling by 11C, having a period of 20 min. The use of O-methyl-[11C]bufotenine to detect serotonin receptors in vivo in mental diseases, is considered.

Hallucinogenic N-methylated indolealkylamines in the cerebrospinal fluid of psychiatric and control populations.

The incidence and quantities of dimethyltryptamine and O-methylbufotenine were studied in the cerebrospinal fluid of patients suffering acute schizophrenic illnesses and in surgical and neurological control groups. Some schizophrenic patients have higher levels of both amines than do controls, though the differences in distribution did not reach statistical significance in the sample studied. The gas-chromatographic technique used is sensitive at the low picogram level.

[Action of LSD and 5-methoxy-N,N-dimethyltryptamine on the high affinity uptake of [3H]-serotonin by isolated rat brain synaptosomes]. / Wirkung von LSD und 5-Methoxy-N,N-dimethyltryptamin auf die aktive Aufnahme von [3H]-Serotonin in Synaptosomenfraktionen aus Rattenhirn.

LSD (10(-7)M--10(-11)M) and 5-methoxy-N,N-dimethyltyptamine (10(-7)--10(-9)M) inhibited the high affinity uptake of [3H]-5HT into synaptosomes. These results suggest that the inhibition of the high affinity uptake is involved in the psychotomimetic action of LSD and 5MeODMT.

Mass spectra of some specifically deuterated tryptamines.

The mass spectra of the four tryptamine derivatives, N-acetyl-5-methoxytryptamine (melatonin), N-acetyl-5-hydroxytryptamine (N-acetyl-serotonin), N,N-dimethyl-5-hydroxtryptamine (bufotenine) and N,N-dimethyl-5-methoxytryptamine (O-methylbufotenine), with specifically labeled [D4] aminoethyl sidechains have been measured. Comparison of these spectra with those of the unlabeled compounds enable the major fragmentations of the compounds to be defined.