Steven A. Barker

9-Diazomethylanthracene as a new fluorescence and ultraviolet label for the spectrometric detection of picomole quantities of fatty acids by high-pressure liquid chromatography.

Abstract 9-Diazomethylanthracene reacts with carboxyl groups to give an ester derivative which can be used as either a fluorescence or ultraviolet label for fatty acid analysis by high-pressure liquid chromatography. The limit of detection by ultraviolet spectroscopy was demonstrated to be approximately 150 pg/μl of the individual fatty acid esters. Fluorescence detection showed a limit of approximately 15 pg/μl. The fluorescence detector response was linear from 0.49 to 14.2 pmol/μl. Thus, derivatization of fatty acids with 9-diazomethylanthracene provides a new and very sensitive method for the quantification of picomole quantities of fatty acids by high-pressure liquid chromatographic techniques using either ultraviolet or fluorescence detection.

Identification and quantification of 1,2,3,4-tetrahydro-β-carboline, 2-methyl-1,2,3,4-tetrahydro-β-carboline, and 6-methoxy-1,2,3,4-tetrahydro-β-carboline as in vivo constituents of rat brain and adrenal gland☆☆☆

Abstract The identification and quantification of three 1,2,3,4-tetrahydro-β-carbolines as normal constitutents of rat brain and adrenal gland, using combined gas chromatographic/mass spectrometric techniques, are reported. Qualitative analyses of these tissues led to the identification of 1,2,3,4-tetrahydro-β-carboline (THBC), 2-methyl-THBC (2-MTHBC) and 6-methoxy-THBC (6-MeOTHBC), as determined by observed peak retention times, mass fragments and ion mass ratios. Quantitative analyses, using deuterated internal standards, gave the following results: THBC (ng/g wet wt) in brain = 17.5 ± 4.86, adrenal = 500.3 ± 163. 6-MeOTHBC (ng/g wet wt) in brain = 35.6 ± 16.6, adrenal = 1113.7 ± 300. Mechanisms for the formation of these β-carbolines as well as their possible function in vivo are discussed.

N, N-dimethyltryptamine: an endogenous hallucinogen.

Publisher Summary This chapter reviews the biosynthesis, metabolism, pharmacology, and properties of N,N-dimethyltryptamine (DMT), leading to a conclusion that DMT may be a neurotransmitter in the mammalian brain. The identification of DMT and other hallucinogens in man explains the experience of hallucinatory phenomena in general. Data is presented in the chapter to illustrate that DMT is a normal constituent of mammalian brain and other tissues. Enzymes capable of synthesizing DMT from tryptamine (TA) and -N-methyltransfera (NMT) are also described. These enzymes are apparently controlled by small peptide-like compounds as well as by feedback inhibition from substrate and product. A cyclic metabolic pathway for DMT is offered. There is also evidence that DMT is taken up into synaptosomes and stored in vesicles by mechanisms identical to those described for known neurotransmitter substances. Specific binding sites for DMT are suggested and DMT is shown to lead to the production of cyclic adenosine monophosphate. (cAMP), a secondary receptor messenger. As evidence of its electrophysiological activity, it has been shown that, DMT stimulates fluid secretion from the salivary glands of blowflies, changes the transepithelial and intracellular potential of the gland, and increases the production of cAMP. Thus, DMT fulfills the criteria for consideration as a neurotransmitter or a neuromodulator per se.

Gas chromatographic/mass spectrometric evidence for the identification of 1,2,3,4-tetrahydro-β-carboline as an invivo constituent of rat brain

Abstract Based on gas chromatographic/mass spectrometric data, obtained using the method of selected ion monitoring, the compound 1,2,3,4-tetrahydro-β-carboline has been tentatively identified as an in vivo constituent of rat brain.

Metabolism of the hallucinogen N,N-dimethyltryptamine in rat brain homogenates☆

Abstract The metabolism of the hallucinogen N , N -dimethyltryptamine (DMT) in whole rat brain homogenate is reported. Studies were conducted using tritiated DMT and DMT- N -oxide (DMT-NO), and metabolites were identified and quantified using thin-layer chromatography and liquid scintillation counting techniques. Metabolite confirmation was obtained by incubation of α,α,β,β-tetradeutero-DMT (DDMT) with whole brain homogenate followed by combined gas chromatographic/mass spectrometric analyses. The metabolites of DMT were identified as indoleacetic acid (IAA), DMT-NO, N -methyltryptamine (NMT), 2-methyl-1,2,3,4-tetrahydro-β-carboline (2-MTHBC), tryptamine (TA) and 1,2,3,4- tetrahydro-β-carboline (THBC). DMT-NO was metabolized to give DMT, NMT, IAA and 2-MTHBC. Formation of these metabolites from DMT-NO was stimulated by anaerobic incubation. Mechanisms for the formation of β-carbolines from DMT and DMT-NO are discussed. The effects of the monamine oxidase inhibitor iproniazid phosphate on DMT metabolism were also studied. Iproniazid inhibited the formation of IAA from DMT by 83 per cent. However, the formation of NMT and DMT-NO was inhibited by 90 per cent under these conditions. Thus, the reported extension of half-life and potentiation of DMT behavioral effects by iproniazid may be due to inhibition of NMT and DMT-NO formation rather than inhibition of monoamine oxidase. A cyclic pathway for the synthesis and metabolism of DMT in brain tissue is proposed.

Gas chromatographic/mass spectrometric evidence for the identification of 6,7-dihydroxy-1, 2,3,4-tetrahydroisoquinoline as a normal constituent of rat brain: Its quantification and comparison to rat whole brain levels of dopamine

Gas chromatographic/mass spectrometric data are presented which demonstrate the presence of 6,7-dihydroxy-1,2,3,4-tetrahydroisoquinoline (DHTIQ) as a normal constituent of rat brain. The level of DHTIQ was calculated to be 10.0 +/- 3.0 ng/g wet weight (+/- S.D., N = 9) of brain tissue while the level of dopamine (DA) was measured as 1.22 +/- 0.22 microg/g (N = 14). The ratio of DHTIQ:DA was thus observed to be approximately 1:100. The possible formation of DHTIQ in alcoholism and schizophrenia is discussed.

In vivo metabolism of α,α,β,β-tetradeutero-n, N-dimethyltryptamine in rodent brain

The metabolism of alpha,alpha,beta,beta- tetradeutero -N,N -dimethyltryptamine ( D4DMT ) in rat brain in vivo as a function of time and dose was examined. Quantification of D4DMT and its respective deutero-metabolites was accomplished using gas chromatographic/mass spectrometric/selected ion monitoring/isotope dilution techniques. The results of this study indicate that D4DMT is metabolized to the corresponding deutero-N-methyltryptamine, tryptamine, 1,2,3,4-tetrahydro-beta-carboline, and 2-methyl-1, 2,3,4-tetrahydro-beta-carboline in rat brain. The subcellular distribution of D4DMT and the aforementioned metabolites is also reported.

Comparison of the brain levels of N,N-dimethyltryptamine and α,α,β,β-tetradeutero-N,N-dimethyltryptamine following intraperitoneal injection: The IN VIVO kinetic isotope effect

A comparison of the brain levels (microgram/g wet weight of tissue) of the hallucinogen N,N-dimethyltryptamine (DMT) and its deuterated analog alpha, alpha, beta, beta-tetradeutero-DMT (D4DMT) as a function of time and dose is reported. It was observed that the presence of deuterium in the alpha- and beta-positions of the ethylamine side-chain led to a potentiation of the level of DMT in brain. Strikingly different dynamics of uptake and clearance were also noted. We propose that these results are due to primary kinetic isotope effect, illustrating the importance of the alpha-position in the metabolism of DMT.

Gas chromatographic/mass spectrometric evidence for the identification of a heptitol and an octitol in human and Octodon degu eye lenses

Gas chromatographic analysis of alditols obtained from post-mortem human and South American rodent Octodon degu eye lenses indicated the presence of two high molecular weight, late eluting components which could not be identified. Thus, the samples were subjected to gas chromatographic/mass spectrometric analysis under both electron impact and chemical ionization conditions. The data obtained from these analyses indicate that both human and Octodon degu lenses contain a heptitol and an octitol, sugars which have not previously been reported to be present in any animal tissue.

Hyperformaldehydism: A unifying hypothesis for the major biochemical theories of schizophrenia

A biochemical hypothesis concerning the etiology of schizophrenia is presented. This hypothesis postulates the presence of a genetically determined lesion in the disposition of one-carbon units leading to elevated levels of formaldehyde, i.e hyperformaldehydism. The relationships between this hypothesis and the existing major biochemical hypotheses of schizophrenia regarding dopamine and transmethylation are discussed.