Tryptophol, 5-hydroxytryptophol and 5-methoxytryptophol induced sleep in mice

Isolation, Characterization, Genome Annotation, and Evaluation of Tyrosinase Inhibitory Activity in Secondary Metabolites of Paenibacillus sp. JNUCC32: A Comprehensive Analysis through Molecular Docking and Molecular Dynamics Simulation

A potential strain, Paenibacillus sp. JNUCC32, was isolated and subjected to whole-genome sequencing. Genome functional annotation revealed its active metabolic capabilities. This study aimed to investigate the pivotal secondary metabolites in the biological system. Fermentation and extraction were performed, resulting in the isolation of seven known compounds: tryptophol (1), 3-(4-hydroxyphenyl)propionic acid (2), ferulic acid (3), maculosin (4), brevianamide F (5), indole-3-acetic acid (6), and butyric acid (7). Tryptophol exhibited favorable pharmacokinetic properties and demonstrated certain tyrosinase inhibitory activity (IC50 = 999 μM). For further analysis of its inhibition mechanism through molecular docking and molecular dynamics (MD) simulation, tryptophol formed three hydrogen bonds and a pro-Michaelis complex with tyrosinase (binding energy = -5.3 kcal/mol). The MD simulation indicated favorable stability for the tryptophol-mushroom tyrosinase complex, primarily governed by hydrogen bond interactions. The crucial residues VAL-283 and HIS-263 in the docking were also validated. This study suggests tryptophol as a potential candidate for antibrowning agents and dermatological research.

Aromatic patterns: Tryptophan aromaticity as a catalyst for the emergence of life and rise of consciousness

Sunlight held the key to the origin of life on Earth. The earliest life forms, cyanobacteria, captured the sunlight to generate energy through photosynthesis. Life on Earth evolved in accordance with the circadian rhythms tied to sensitivity to sunlight patterns. A unique feature of cyanobacterial photosynthetic proteins and circadian rhythms' molecules, and later of nearly all photon-sensing molecules throughout evolution, is that the aromatic amino acid tryptophan (Trp) resides at the center of light-harvesting active sites. In this perspective, I review the literature and integrate evidence from different scientific fields to explore the role Trp plays in photon-sensing capabilities of living organisms through its resonance delocalization of π-electrons. The observations presented here are the product of apparently unrelated phenomena throughout evolution, but nevertheless share consistent patterns of photon-sensing by Trp-containing and Trp-derived molecules. I posit the unique capacity to transfer electrons during photosynthesis in the earliest life forms is conferred to Trp due to its aromaticity. I propose this ability evolved to assume more complex functions, serving as a host for mechanisms underlying mental aptitudes - a concept which provides a theoretical basis for defining the neural correlates of consciousness. The argument made here is that Trp aromaticity may have allowed for the inception of the mechanistic building blocks used to fabricate complexity in higher forms of life. More specifically, Trp aromatic non-locality may have acted as a catalyst for the emergence of consciousness by instigating long-range synchronization and stabilizing the large-scale coherence of neural networks, which mediate functional brain activity. The concepts proposed in this perspective provide a conceptual foundation that invites further interdisciplinary dialogue aimed at examining and defining the role of aromaticity (beyond Trp) in the emergence of life and consciousness.

The Uniqueness of Tryptophan in Biology: Properties, Metabolism, Interactions and Localization in Proteins

Tryptophan (Trp) holds a unique place in biology for a multitude of reasons. It is the largest of all twenty amino acids in the translational toolbox. Its side chain is indole, which is aromatic with a binuclear ring structure, whereas those of Phe, Tyr, and His are single-ring aromatics. In part due to these elaborate structural features, the biosynthetic pathway of Trp is the most complex and the most energy-consuming among all amino acids. Essential in the animal diet, Trp is also the least abundant amino acid in the cell, and one of the rarest in the proteome. In most eukaryotes, Trp is the only amino acid besides Met, which is coded for by a single codon, namely UGG. Due to the large and hydrophobic π-electron surface area, its aromatic side chain interacts with multiple other side chains in the protein, befitting its strategic locations in the protein structure. Finally, several Trp derivatives, namely tryptophylquinone, oxitriptan, serotonin, melatonin, and tryptophol, have specialized functions. Overall, Trp is a scarce and precious amino acid in the cell, such that nature uses it parsimoniously, for multiple but selective functions. Here, the various aspects of the uniqueness of Trp are presented in molecular terms.

From conifers to cognition: Microbes, brain and behavior

A diversity of bacteria, protozoans and viruses ("endozoites") were recently uncovered within healthy tissues including the human brain. By contrast, it was already recognized a century ago that healthy plants tissues contain abundant endogenous microbes ("endophytes"). Taking endophytes as an informative precedent, we overview the nature, prevalence, and role of endozoites in mammalian tissues, centrally focusing on the brain, concluding that endozoites are ubiquitous in diverse tissues. These passengers often remain subclinical, but they are not silent. We address their routes of entry, mechanisms of persistence, tissue specificity, and potential to cause long-term behavioral changes and/or immunosuppression in mammals, where rabies virus is the exemplar. We extend the discussion to Herpesviridae, Coronaviridae, and Toxoplasma, as well as to diverse bacteria and yeasts, and debate the advantages and disadvantages that endozoite infection might afford to the host and to the ecosystem. We provide a clinical perspective in which endozoites are implicated in neurodegenerative disease, anxiety/depression, and schizophrenia. We conclude that endozoites are instrumental in the delicate balance between health and disease, including age-related brain disease, and that endozoites have played an important role in the evolution of brain function and human behavior.

The impact of SO2 on wine flavanols and indoles in relation to wine style and age

Wine has one of the broadest chemical profiles, and the common oenological practice of adding the antioxidant and antimicrobial sulfur dioxide has a major impact on its metabolomic fingerprint. In this study, we investigated novel discovered oenological reactions primarily occurring between wine metabolites and sulfur dioxide. The sulfonated derivatives of epicatechin, procyanidin B2, indole acetic acid, indole lactic acid and tryptophol were synthesized and for the first time quantified in wine. Analysis of 32 metabolites in 195 commercial wines (1986-2016 vintages) suggested that sulfonation of tryptophan metabolites characterised white wines, in contrast to red wines, where sulfonation of flavanols was preferred. The chemical profile of the oldest wines was strongly characterised by sulfonated flavanols and indoles, indicating that could be fundamental metabolites in explaining quality in both red and white aged wines. These findings offer new prospects for more precise use of sulfur dioxide in winemaking.

Physiological and pharmacological properties of 5-methoxytryptophol

5-methoxytryptophol (5-ML) is a pineal indoleamine derived from serotonin shown to be biologically active in a number of species. This indolamine exhibits a circadian pattern synchronized with the day-night cycle with significant increases during daylight, already recognized in vertebrates. The multiplicity of physiological and endocrine functions of 5-ML is remarkable; it is involved in circadian rhythms, reproduction and sexual processes. Furthermore, a number of pharmacological benefits of 5-ML have been reported, including immunomodulatory, antitumor and antioxidative activities. However, the molecular mechanisms of these pharmacological effects remain unclear. The purpose of this article is to provide an overview on the general properties and physiological functions of 5-ML. An attempt has been made to fully document all studies performed using 5-ML. In addition, this article aims to gain insight into the current state of knowledge regarding pharmacological and therapeutic effects of this indoleamine.

New approaches in the management of insomnia: weighing the advantages of prolonged-release melatonin and synthetic melatoninergic agonists

Hypnotic effects of melatonin and melatoninergic drugs are mediated via MT(1) and MT(2) receptors, especially those in the circadian pacemaker, the suprachiasmatic nucleus, which acts on the hypothalamic sleep switch. Therefore, they differ fundamentally from GABAergic hypnotics. Melatoninergic agonists primarily favor sleep initiation and reset the circadian clock to phases allowing persistent sleep, as required in circadian rhythm sleep disorders. A major obstacle for the use of melatonin to support sleep maintenance in primary insomnia results from its short half-life in the circulation. Solutions to this problem have been sought by developing prolonged-release formulations of the natural hormone, or melatoninergic drugs of longer half-life, such as ramelteon, tasimelteon and agomelatine. With all these drugs, improvements of sleep are statistically demonstrable, but remain limited, especially in primary chronic insomnia, so that GABAergic drugs may be indicated. Melatoninergic agonists do not cause next-day hangover and withdrawal effects, or dependence. They do not induce behavioral changes, as sometimes observed with z-drugs. Despite otherwise good tolerability, the use of melatoninergic drugs in children, adolescents, and during pregnancy has been a matter of concern, and should be avoided in autoimmune diseases and Parkinsonism. Problems and limits of melatoninergic hypnotics are compared.

Indoleamines and 5-methoxyindoles in trout pineal organ in vivo: daily changes and influence of photoperiod

This study describes the diel rhythms in several indoleamines, melatonin, and related 5-methoxyindoles in the pineal organ of rainbow trout in vivo. In addition, the effect of different photoperiod conditions was evaluated. Melatonin levels displayed clear daily rhythms in the pineal organ of rainbow trout kept experimentally under long (LD 16:08), neutral (LD 12:12), and short (LD 08:16) photoperiods. Duration of melatonin signal was dependent on the night length of prevailing photoperiod, while peak amplitude was higher when lengthening the photoperiod. Significant daily rhythms in 5-HT content, the precursor of melatonin synthesis, were found in neutral and short photoperiod with increases of the amine content just after the light-dark interphase and decreases in the middle of the night, which were more important under short photoperiod. In contrast, no significant 24-h cyclic variation was found in pineal 5-HT content under long photoperiod. Daily profiles in the content of the main 5-HT oxidative metabolite, the 5-hydroxyindoleacetic acid (5-HIAA), outlined those of the amine precursor. The chronograms of both aminergic compounds contrast with those of 5-hydroxytryptophan content, which displayed a net tendency to increase at night. This study also provides evidence for the existence of daily cyclic changes in the content of 5-methoxytryptamine (5-MT), 5-methoxyindoleacetic acid (5-MIAA), and 5-methoxytryptophol (5-MTOL) in trout pineal organ, which were also dependent on photoperiod. The 24-h profiles in 5-MT content correlated well with those of 5-HT, showing a peak at the first hour of darkness in all photoperiodic conditions, and a decay at midnight only in both neutral and long photoperiods. Similarly, the content of 5-MTOL also displayed high values during the day-night transition in trout kept under neutral and long photoperiods, followed by a slow decay all along the night. Finally, levels of 5-MIAA increased in all photoperiods when lights were turned off, being this nocturnal increase maximal in fish kept under LD 16:08. These results suggest that light-dark cycle modulates daily rhythms in pineal indoles and non-melatonin 5-methoxyindoles by acting mainly through the melatonin synthesis activity, which limits the availability of 5-HT for the oxidative and direct methylation pathways. In addition, it seems that a nocturnally increased synthesis of 5-HT might be a requirement for the optimal formation of melatonin and other 5-methoxyindoles in the pineal organ when trout remain under short photoperiods.

5-hydroxytryptophol as a marker for recent alcohol intake

AIMS

To review the mechanism behind the alcohol-induced shift in serotonin metabolism, and the use of urinary 5-hydroxytryptophol (5-HTOL) as a biochemical marker of acute alcohol consumption.

BACKGROUND

The serotonin metabolite 5-HTOL is a normal, minor constituent of urine and is excreted mainly in conjugated form with glucuronic acid. The formation of 5-HTOL increases dramatically after alcohol intake, due to a metabolic interaction, and the elevated urinary excretion remains for some time (>5-15 hours depending on dose) after ethanol has been eliminated. This biochemical effect can be used for detection of recent alcohol intake.

RESULTS

5-HTOL is determined by the gas chromatography-mass spectrometry (GC-MS) or liquid chromatography and mass spectrometry (LC-MS) techniques. A new ELISA method for 5-HTOL glucuronide provides a promising clinical assay. The most robust way to use the marker is by measuring the ratio of 5-HTOL to 5-hydroxyindoleacetic acid, because this compensates for urine dilution and dietary intake of serotonin. 5-HTOL is a very sensitive and specific indicator of recent alcohol consumption and, as such, a valuable complement to self-report. In clinical use, 5-HTOL is effective for monitoring lapses into drinking during out-patient treatment and for objective evaluation of treatment efforts. Other applications include detection of high-risk patients in elective surgery, monitoring of disulfiram treatment and a method to rule out artefactual ethanol formation in forensic toxicology. 5-HTOL can also be used as a sensitive reference method for validation of self-report data in clinical alcohol research.

CONCLUSIONS

An elevated urinary 5-HTOL level can serve as a sensitive and reliable marker for recent alcohol intake with a number of clinical and forensic applications.

Anti-dipsotropic isoflavones: the potential therapeutic agents for alcohol dependence

Daidzin is the active principle of Radix puerariae (RP), an herbal remedy that has been used apparently safely and effectively for the treatment of "alcohol addiction" in China for more than a millennium. It has been shown to reduce alcohol consumption in all animal models tested to date. A link between daidzin's capacity to reduce alcohol consumption and its ability to increase liver mitochondrial monoamine oxidase (MAO): aldehyde dehydrogenase (ALDH-2) activity ratio has been established. Daidzin analogs that potently inhibit ALDH-2 but not MAO are the most anti-dipsotropic, whereas those that also inhibit MAO are not. On the basis of these findings, it was proposed that the liver mitochondrial MAO-ALDH-2 pathway is the primary site of action of daidzin and that a biogenic aldehyde derived from the action of MAO mediates its anti-dipsotropic action. Therefore, to design and synthesize more potent anti-dipsotropic analogs, structural features that would enhance ALDH-2 inhibition and/or decrease MAO inhibition needed to be evaluated. Structure-activity-relationship (SAR) studies have revealed that a sufficient set of criteria for a potent anti-dipsotropic analog is an isoflavone with a free 4'-OH function and a straight-chain alkyl at the 7 position that has a terminal polar function such as -OH, -COOH, or -NH2. The preferable chain lengths for the 7-O-omega-carboxy, 7-O-omega-hydroxy, and 7-O-omega-amino substituents are 5 < or = n < or = 10, 2 < or = n < or = 6, and n > or = 4, respectively. Analogs that meet these criteria have increased potency for ALDH-2 inhibition and/or decreased potency for MAO inhibition and are, therefore, likely to be potent anti-dipsotropic agents.

Elevated brain 5-hydroxytryptophol levels in experimental portal-systemic encephalopathy

Brain tissue levels of the two serotonin metabolites 5-hydroxytryptophol and 5-hydroxyindole-3-acetic acid (5-HIAA) were measured in porta-caval shunted rats, an in vivo model of portal-systemic encephalopathy. An intraperitoneal challenge of L-tryptophan (280 mg/kg body weight) to sham-operated rats was also instituted to increase the brain serotonin metabolism in these rats. The results revealed significant increases in 5-hydroxytryptophol (by 31% and 5-HIAA (by 87%) brain levels in porta-caval shunted rats as compared to sham-operated controls. The brain 5-hydroxytryptophol-to-5-HIAA ratio was lower in the porta-caval shunted rats. The 5-hydroxytryptophol levels in sham rats after the L-tryptophan challenge were intermediate between the porta-caval shunted and sham rats but not statistically significant for either group. These results suggest that increased brain 5-hydroxytryptophol levels might be associated with the pathogenesis of portal-systemic encephalopathy. Further, the elevated brain 5-hydroxytryptophol levels in experimental portal-systemic encephalopathy are probably a result of the increased brain serotonin metabolism prevailing in this condition rather than changes in the brain redox potential.

Regulation of melatonin synthesis in the ovine pineal gland

The results presented here show clearly that the rapid nocturnal increase in circulating melatonin in sheep is associated with an equally rapid increase in melatonin production in the pineal gland. Pineal NAT activity and NAS concentration also increased under this condition, indicating that NAT activity is an important factor in this process. According to the current model for the regulation of pineal melatonin production in the rat, the large nocturnal increase in NAT activity is the major factor responsible for the daily rhythm in melatonin, as well as for the opposite rhythm in serotonin and its oxidation products in the pineal gland. Increased NAT activity in the pineal gland at night channels serotonin toward melatonin production at an enhanced rate, thereby causing pineal serotonin levels to drop. This, in turn, leads to decreased production of oxidative metabolites due to reduced substrate availability for MAO. Thus, the large increase in NAT activity acts as the key factor, directly or indirectly, for the generation of all rhythms in serotonin metabolites in the pineal gland, and possibly in the circulation. Such an exclusive role for NAT is doubtful in the sheep pineal gland for the following reasons: First, the nocturnal increase in NAT activity is relatively small (3-5-fold) compared to the rat (50-100-fold). Second, in at least two instances--a 30 min light pulse and prazosin treatment--there was a clear dissociation between melatonin production and NAT activity. This lack of correlation between NAT activity and melatonin production does not seem to be due to serotonin availability since serotonin levels did not change under the above conditions. Further, serotonin levels were found to decrease rather than increase when melatonin levels increased at night. Finally, our observation that melatonin production can be increased during the day by increasing serotonin levels in the pineal gland may reflect only the incompletely saturated nature of pineal NAT and may have little relevance for the physiological regulation of pineal melatonin production. Even though NAT activity may not be the only factor responsible for the rhythmic production of serotonin metabolites in sheep pineal gland, activation of the serotonin----melatonin pathway seems to be the primary metabolic response involved in this regulation, since the rhythms in the serotonin metabolites are similar in both rat and sheep. In the rat, the activation of the serotonin----melatonin pathway is brought about exclusively by the increase in NAT activity.(ABSTRACT TRUNCATED AT 400 WORDS)

Age-related changes of serotonin and its metabolites content in the visual system of the rat

Measurements have been taken of the serotonin and its metabolites (tryptophan, 5-hydroxytryptophan, 5-hydroxy-3-indolacetic acid and 5-hydroxytryptophol) in each structure of the geniculate and extrageniculate visual system of rats aged between 3 and 30 months. The concentration of tryptophan was the highest of all compounds studied. Its increase during ageing is statistically significant in the lateral geniculate and posterior thalamus. 5-HTP concentration was very low and in some cases not detectable. 5-HT concentrations and its principal metabolite, 5-HIAA, showed a different profile in each brain structure. The lateral geniculate and visual cortex showed statistically significant changes, but with opposite results. In the lateral geniculate the 5-HT and 5-HIAA concentrations were increased during the ageing period. However, in the visual cortex the 5-HT and 5-HIAA concentrations decreased in the same period. These age-related changes were not seen in the superior colliculus and posterior thalamus as in the 5-HT levels as in the 5-HIAA. 5-hydroxytryptophol was always found in low concentration. These results suggest age-related changes in the geniculate visual system.

Investigation of circadian rhythms for pineal 5-hydroxytryptophol and other indoles in the rat

5-hydroxytryptophol (5HTL) occurs in the pineal gland of the rat at levels comparable to those of melatonin, yet few studies have been conducted to investigate 5HTL as a potential alternative pineal hormone. In this study the pineals of 90-day-old male Sprague Dawley rats have been assayed by high performance liquid chromatography coupled with electrochemical detection. Significant (P less than .0001) circadian variation was measured in 5HTL levels, and a fivefold plateau elevation occurred during the middle of the light period. By comparison with the timing of the variations in N-acetyl serotonin and melatonin levels, it is suggested that 5HTL may not be regulated by simple competition with N-acetyl transferase for the common substrate 5HT but may, in fact, be regulated independently. Literature supporting such a suggestion, and a model incorporating it, are presented for discussion.

Pineal indoles: significance and measurement

Despite intensive investigation, particularly over the past fifteen years, many aspects of pineal function with respect to mammalian physiology remain obscure. Much of this work is reviewed and particular attention focussed on indole metabolism within the pineal gland. Emphasis is placed on the development of new analytical techniques with special reference to high performance liquid chromatography coupled with electrochemical detection. The growth in knowledge regarding pineal indole synthesis which can be attributed to the use of this technique is discussed. The possibility that pineal indoles other than melatonin may function as hormones or neuromodulators is considered. A functional role for 5-hydroxytryptophol as a neuromodulator, possibly associated with diffuse neuroendocrine function (amine precursor, uptake and decarboxylation, APUD) is suggested.

Measurement of 5-hydroxytryptophol and 5-hydroxyindoleacetic acid in human and rat brain and plasma

The levels of 5-hydroxyindoleacetic acid (5-HIAA) and free and total 5-hydroxytryptophol (5-HTOL) in human and rat brain regions and plasma were determined by a specific capillary column gas chromatographic--mass spectrometric method. The human brains were obtained 2-3 hours post mortem, and the levels of 5-HIAA were in the range of 0.48-31.3 nmoles/g in the regions investigated. The levels of free and total 5-HTOL were 10.9-387 pmoles/g and 14.5-821 pmoles/g, respectively. The ratio of total 5-HTOL to 5-HIAA was in the range of 0.6-5.5%. In human plasma the levels of free and total 5-HTOL were 0.9 +/- 0.3 and 2.9 +/- 0.8 pmoles/ml +/- S.E.M., respectively. In regions of rat brain, the 5-HIAA levels ranged from 0.37-2.84 nmoles/g. Free and total 5-HTOL were in the range of 11.4-56.1 and 16.2-77.1 pmoles/g, respectively. The ratio of total 5-HTOL and 5-HIAA ranged from 2.3-5.1%. Higher levels of 5-HIAA and 5-HTOL occurred in the rat pineal gland. In rat plasma the levels of free and total 5-HTOL were 1.34 +/- 0.06 and 21.6 +/- 1.6 pmoles/ml +/- S.E.M., respectively.

Determination of endogeneous indoleacetic acid and tryptophol in mouse brain by high performance liquid chromatography with fluorometric detection

A simple and sensitive method using high performance liquid chromatography with fluorometric detection has been developed for the identification and quantitation of the endogeneous tryptamine metabolites, indoleacetic acid (IAA) and tryptophol (TOL) in the normal mouse brain. The limits of sensitivity are 5pg for both IAA and TOL. The extract procedure from the brain is only to deproteinize samples. The mean concentrations of IAA and TOL in the mouse brain are 8.99 +/- 0.31 ng/g and 3.56 +/- 0.21 ng/g respectively. The effects of pargyline and tryptamine on the levels of IAA and TOL were also studied.

Simultaneous determination of tryptophan and its metabolites in mouse brain by high-performance liquid chromatography with fluorometric detection

A new method for the determination of tryptophan and its metabolites in a single mouse brain using high-performance liquid chromatography (HPLC) with fluorometric detection is described. Tryptophan, serotonin, 5-hydroxyindoleacetic acid, indoleacetic acid, and tryptophol were clearly separated by a C8 reverse-phase column. Tissue preparation is performed only to centrifuge homogenates of brain prior to the injection to HPLC. The sensitivity is in the range from 10 to 15 pg.

5-hydroxytryptophol in the cerebrospinal fluid and urine of alcoholics and healthy subjects

The serotonin metabolite 5-hydroxytryptophol was determined in cerebrospinal fluid and urine of alcoholics and healthy subjects, by a glass capillary gas chromatographic-mass spectrometric method. The urinary excretion rate (14.6 +/- 2.9 pmoles/mumoles creatinine) and urine (109 +/- 20 pmoles/ml) and cerebrospinal fluid (4.12 +/- 0.21 pmoles/ml) concentrations in healthy subjects were established. Only 1% of the 5-hydroxytryptophol in urine occurred in free form. Ethanol ingestion (80, 120 g) by healthy subjects lead to a 20--100-fold increase in the urinary excretion rate of 5-hydroxytryptophol. In cerebrospinal fluid the increase was about 60%. Alcoholics had increased urinary excretion rates and cerebrospinal fluid levels during intoxication, which were in the same range as in intoxicated healthy subjects. During recovery from intoxication, the 5-hydroxytryptophol level in alcoholics decreased, but the CSF levels were still higher than in healthy subjects.

Reduction in brain glucose utilization rate after tryptophol (3-indole ethanol) treatment

3-Indole ethanol has been recently identified as the hypnotic agent in trypanosomal sleeping sickness, and because it is formed in vivo after ethanol or disulfiram treatment, is also associated with the study of alcoholism. When administered intraperitoneally to rats (250 mg/kg) tryptophol induced a sleep-like state that lasted less than an hour (no righting reflex was apparent 2 min after injection, but it returned at 11 min in bovine serum albumin solution, and 47 min in 40% ethanol solution). In ethanol solutions, tryptophol reduced brain cortical glucose utilization by 55% to the basal brain metabolic rate, and this effect lasted less than 1 h. Synergistic effects of tryptophol and ethanol were suggested by the observation that in albumin solution, tryptophol reduced brain glucose utilization by 35%, but a normal rate was not observed until 2 h postinjection.

Concentration of serotonin metabolites in the cerebrospinal fluid from alcoholics before and during disulfiram therapy

The levels of 5-hydroxytryptophol and 5-hydroxyindoleacetic acid were measured in the cerebrospinal fluid before and after one week of disulfiram treatment (400 mg/day) from ten male hospitalized alcoholic patients. The disulfiram treatment induced elevated (P less than 0.001) levels of 5-hydroxytryptophol. The levels were higher than in a control group, both before (P less than 0.01) and after (P less than 0.001) the treatment. No effects on the levels of 5-hydroxyindoleacetic acid were noted. The results indicate an altered serotonin metabolism in alcoholics, which is further potentiated by disulfiram treatment.

[Chemical mechanism of the effect of alcohol]

The formation of tetrahydro-isoquinoline alkaloids in human and animal metabolisms subsequent to alcohol consumption is reported. The spectrum of identified products ranges from simple structures such as salsolinol to the complicated skeleton of protoberberines. These substances, hitherto found exclusively in plants, interfere with the biosynthesis, biodegradation and neurotransmission of the structurally closely related biogenic amines from which they are formed, and thus affect the vegetative nervous system.

Suppression of ethanol withdrawal by dopamine

An ethanol-inhalation technique was used to determine a potential relationship between dopamine and central nervous effects produced by alcohol. Both L-DOPA and intracranially injected dopamine resulted in attenuation of ethanol-induced withdrawal convulsion scores, whereas, haloperidol, a known dopaminergic blocker was found to significantly increase convulsion scores.

Potentiation of ethanol narcosis by dopamine- and l-DOPA-based isoquinolines

The isoquinolines, salsolinol and 3-carboxysalsolinol, prolong ethanol-induced narcosis in mice. Pretreatment with carbidopa increases the effect of 3-carboxysalsolinol but not of salsolinol. These results suggest that ethanol sleeping-time potentiation by l-LOPA may involve a partial conversion to the isoquinoline in vivo. A central depressant action of salsolinol or the 3-carboxy analogue is suggested.

Effect of ethanol on the oxidative metabolism of tryptamine by rat liver homogenate

1 The effect of a wide range of ethanol concentrations (v/v) on indoleacetic acid (IAA) formation from the oxidative deamination of tryptamine was studied in vitro, in rat whole liver homogenate.2 IAA production was inhibited progressively by ethanol in concentrations between 0.01% to 0.2%, but the inhibition declined when the ethanol concentration was increased further to 6%.3 Ethanol-induced inhibition of IAA formation was only partially reversed by excess aldehyde dehydrogenase, whereas reductions in IAA formation were completely prevented by pyrazole or ethanol (6% and 10%) itself.4 Excess nicotinamide adenine dinucleotide failed to alter the inhibitory effect of ethanol and no evidence was obtained for inhibition of monoamine oxidase by ethanol or its metabolite, acetaldehyde.5 We conclude that ethanol indirectly inhibits IAA production as a result of oxidation of ethanol by alcohol dehydrogenase, during which the oxidative metabolism of tryptamine is shifted towards the reductive pathway, thus favouring the formation of tryptophol in place of IAA.

Tryptophol formation by Zygosaccharomyces priorianus

Zygosaccharomyces priorianus converted L-tryptophan to tryptophol and to small quantities of indole-3-acetic acid. Neither tryptophol nor indole-3-acetic acid was metabolized when added separately to growing cultures. The possible intermediacy of indole-3-pyruvic acid, indole-3-acetaldehyde, and tryptamine in the degradation of L-tryptophan was tested by feeding these compounds to Z. priorianus and Saccharomyces cerevisiae. Indole-3-pyruvic acid and indole-3-acetaldehyde were converted to tryptophol and indole-3-acetic acid, with the latter accumulating only in small amounts. Tryptamine was converted to its N-acetyl derivative by these organisms. A qualitative study was made on the metabolism of L-phenylalanine, L-tyrosine, and L-5-hydroxytryptophan by these organisms. Like L-tryptophan, these amino acids were metabolized to their respective alcohol and acid derivatives. Of a large number of organisms tested, the yeasts possessed the highest capacity for degrading L-tryptophan to tryptophol.

Prostaglandin E1 causes sedation and increases 5-hydroxytryptamine turnover in rat brain

1. Administration of prostaglandin E(1) (1 mg/kg, i.p.) to rats induced sedation and a decrease in muscular tone. Prostaglandin E(1)-induced sedation was accompanied by the low voltage-high frequency E.E.G. pattern characteristic of the waking animal.2. Administration of prostaglandin E(1) also increased the turnover rate of 5-hydroxytryptamine and raised the concentration of acetylcholine in brain.3. The behavioural effects of prostaglandin were blocked by prior administration of p-chlorophenylalanine or pargyline, drugs which lowered the brain concentration of 5-hydroxyindoleacetic acid (5-HIAA), and was potentiated by pretreatment with probenecid, which elevated the 5-HIAA concentration. Pretreatment with atropine sulphate failed to alter prostaglandin E(1)-induced sedation.4. The results are compatible with the possibility that prostaglandin E(1) induces a state resembling paradoxical sleep through an action on 5-hydroxytryptamine metabolism in brain.