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Neuropathic pain is an important public health problem for which only a few treatments are available. Preclinical studies show that melatonin (MLT), a neurohormone acting on MT1 and MT2 receptors, has analgesic properties, likely through MT2 receptors. Here, we determined the effects of the novel selective MLT MT2 receptor partial agonist N-{2-([3-bromophenyl]-4-fluorophenylamino)ethyl}acetamide (UCM924) in 2 neuropathic pain models in rats and examined its supraspinal mechanism of action. In rat L5-L6 spinal nerve ligation and spared nerve injury models, UCM924 (20-40 mg/kg, subcutaneously) produced a prolonged antinociceptive effect that is : (1) dose-dependent and blocked by the selective MT2 receptor antagonist 4-phenyl-2-propionamidotetralin, (2) superior to a high dose of MLT (150 mg/kg) and comparable with gabapentin (100 mg/kg), but (3) without noticeable motor coordination impairments in the rotarod test. Using double staining immunohistochemistry, we found that MT2 receptors are expressed by glutamatergic neurons in the rostral ventrolateral periaqueductal gray. Using in vivo electrophysiology combined with tail flick, we observed that microinjection of UCM924 into the ventrolateral periaqueductal gray decreased tail flick responses, depressed the firing activity of ON cells, and activated the firing of OFF cells; all effects were MT2 receptor-dependent. Altogether, these data demonstrate that selective MT2 receptor partial agonists have analgesic properties through modulation of brainstem descending antinociceptive pathways, and MT2 receptors may represent a novel target in the treatment of neuropathic pain.

BackgroundAntisocial personality disorder (ASPD) is characterised by elevated impulsive aggression and increased risk for criminal behaviour and incarceration. Deficient activity of the monoamine oxidase A (MAOA) gene is suggested to contribute to serotonergic system dysregulation strongly associated with impulsive aggression and antisocial criminality.AimsTo elucidate the role of epigenetic processes in altered MAOA expression and serotonin regulation in a population of incarcerated offenders with ASPD compared with a healthy non-incarcerated control population.MethodParticipants were 86 incarcerated participants with ASPD and 73 healthy controls. MAOA promoter methylation was compared between case and control groups. We explored the functional impact of MAOA promoter methylation on gene expression in vitro and blood 5-HT levels in a subset of the case group.ResultsResults suggest that MAOA promoter hypermethylation is associated with ASPD and may contribute to downregulation of MAOA gene expression, as indicated by functional assays in vitro, and regression analysis with whole-blood serotonin levels in offenders with ASPD.ConclusionsThese results are consistent with prior literature suggesting MAOA and serotonergic dysregulation in antisocial populations. Our results offer the first evidence suggesting epigenetic mechanisms may contribute to MAOA dysregulation in antisocial offenders.

The possible role of melatonin in melanogenesis was investigated by performing reactions of melatonin with peroxidase + H2O2 or H2O2 only, in the presence or absence of UV irradiation. Samples of the reaction mixtures were drawn at different times (from 15 to 480 min), the enzyme (when present) was removed by ultrafiltration and the samples so obtained were analyzed by MALDI/MS. The results show that melatonin undergoes oligomerization reaction with peroxidase + H2O2, leading to heptameric species. For high reaction times the MALDI/MS data do not show the formation of larger oligomers, but UV-vis spectroscopy indicates that the oligomerization processes proceed. The failure of MALDI-TOF in the identification of larger oligomers was related to the chemical-physical and morphological behavior of melanins. In the case of UV irradiation, the formation of species originating from the O- and O2 addition to melatonin, which activate new oligomerization channels, has been observed.

In order to investigate the role of tryptophan and its metabolites in biogenesis of melanins, a study on the enzymatic reaction of 3-hydroxykynurenine with tyrosinase and peroxidase was performed. The reaction at different pH values was monitored by sampling at different times, with ultrafiltration used before analysis by matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS). The data obtained in this way showed that oligomerization processes take place with both enzymes, but with different behaviour, also depending on pH. 3-Hydroxykynurenine in the presence of tyrosinase at pH 6.0 leads to formation of xanthommatin, and at pH 8.0 hydroxanthommatin is formed in the first step of the reaction followed by formation of black-brown pigments. In contrast, the formation of oligomerization products by peroxidase action is observed in high yields under both acidic and basic conditions; however, at pH 6.0, a more extensive oligomerization process is observed. Thus peroxidase is able to activate oligomerization analogous to that observed in the case of tyrosinase without depending on the variation of pH. Due to the early formation of decarboxylated hydroxykynurenine, hydroxanthommatin and decarboxylated hydroxanthommatin, the enzymatic reaction leads to mixed oligomers, which can be considered as precursors of new pathways in pigment production.

The neurohormone melatonin activates two G-protein coupled receptors, MT1 and MT2. Melatonin is implicated in circadian rhythms and sleep regulation, but the role of its receptors remains to be defined. We have therefore characterized the spontaneous vigilance states in wild-type (WT) mice and in three different types of transgenic mice: mice with genetic inactivation of MT1 (MT1(-/-)), MT2 (MT2(-/-)) and both MT1/MT2 (MT1(-/-)/MT2(-/-)) receptors. Electroencephalographic (EEG) and electromyographic sleep-wake patterns were recorded across the 24-h light-dark cycle. MT1(-/-)mice displayed a decrease (-37.3%) of the 24-h rapid eye movement sleep (REMS) time whereas MT2(-/-)mice showed a decrease (-17.3%) of the 24-h non rapid eye movement sleep (NREMS) time and an increase in wakefulness time (14.8%). These differences were the result of changes occurring in particular during the light/inactive phase. Surprisingly, MT1(-/-)/MT2(-/-) mice showed only an increase (8.9%) of the time spent awake during the 24-h. These changes were correlated to a decrease of the REMS EEG theta power in MT1(-/-)mice, of the NREMS EEG delta power in MT2(-/-)mice, and an increase of the REMS and wakefulness EEG theta power in MT1(-/-)/MT2(-/-) mice. Our results show that the genetic inactivation of both MT1 and MT2 receptors produces an increase of wakefulness, likely as a result of reduced NREMS due to the lack of MT2 receptors, and reduced REMS induced by the lack of MT1 receptors. Therefore, each melatonin receptor subtype differently regulates the vigilance states: MT2 receptors mainly NREMS, whereas MT1 receptors REMS.

Patients experiencing mental disorders are at an elevated risk for developing aggressive behavior. In the past 10 years, the psychopharmacological treatment of aggression has changed dramatically owing to the introduction of atypical antipsychotics on the market and the increased use of anticonvulsants and lithium in the treatment of aggressive patients.This review (second of 2 parts) uses a translational medicine approach to examine the neurobiology of aggression, discussing the major neurotransmitter systems implicated in its pathogenesis (serotonin, glutamate, norepinephrine, dopamine, and γ-aminobutyric acid) and the neuropharmacological rationale for using atypical antipsychotics, anticonvulsants, and lithium in the therapeutics of aggressive behavior. A critical review of all clinical trials using atypical antipsychotics (aripiprazole, clozapine, loxapine, olanzapine, quetiapine, risperidone, ziprasidone, and amisulpride), anticonvulsants (topiramate, valproate, lamotrigine, and gabapentin), and lithium are presented. Given the complex, multifaceted nature of aggression, a multifunctional combined therapy, targeting different receptors, seems to be the best strategy for treating aggressive behavior. This therapeutic strategy is supported by translational studies and a few human studies, even if additional randomized, double-blind, clinical trials are needed to confirm the clinical efficacy of this framework.

The bark of several coniferous species, a waste product of the timber industry, contains significant amounts of natural antioxidants. In our ongoing studies of Nepalese medicinal plants, we examined the bark from Abies spectabilis as the starting material for extracting antioxidant compounds. In vitro antioxidant activity evaluated by means of three antioxidant methods, namely 2,2-diphenyl-1-picrylhydrazyl (DPPH), Briggs-Rauscher oscillating reaction (BR) and Trolox Equivalent Antioxidant Capacity (TEAC) and total phenol contents with the Folin-Ciocalteau reagent; the ferrous iron chelating capacity was also assessed. The methanol extract of A. spectabilis showed significant antioxidant activity and polyphenol contents (IC 50 4.13 µg/mL, 0.20 μg/mL eq. resorcinol, 4.22 mM eq. Trolox, 3.9 µg/g eq. gallic Acid in the DPPH, BR, TEAC and Folin-Ciocalteau tests, respectively) and weak Fe 2+ chelating capacity. Phytochemical studies were also carried out with 1D- and 2D NMR experiments and DI-ESI-MS, HPLC-DAD and LC-MSn measurements. Oligomeric C-type proanthocyanidins, mainly trimeric gallocatechin derivatives, were the most abundant compounds (16% of extract expressed as procyanindin B1). Gallocatechin oligomers (up to six units) and prodelphynidin-gallocatechin polymers were also identified in the extract. Prodelphynidin B4, cyclograndisolide and trans-docosanil ferulate were also isolated and characterized by NMR and MS spectroscopy.

Melatonin (MLT) is a neurohormone known to be involved in the regulation of anxiety. Most of the physiological actions of MLT in the brain are mediated by two high-affinity G-protein-coupled receptors, denoted MT(1) and MT(2). However, the particular role of these receptors in anxiety remains to be defined. Here we used a novel MT(2)-selective partial agonist, UCM765 to evaluate the involvement of MT(2) receptors in anxiety. Adult male rats were acutely injected with UCM765 (5-10-20mg/kg), MLT (20mg/kg) or diazepam (DZ, 1mg/kg). Anxiety-related behaviors were assessed in the elevated plus maze test (EPMT), novelty suppressed feeding test (NSFT) and open field test (OFT). UCM765 at the dose of 10mg/kg showed anxiolytic-like properties by increasing the time spent in the open arm of the EPMT, and by reducing the latency to eat in a novel environment in the NSFT. In the EPMT, animals treated with UCM765 (10mg/kg) or MLT (20mg/kg) spent more time in the open arms compared to vehicle-treated animals, but to a lesser extent compared to DZ (1mg/kg). In the NSFT, all treatments similarly decreased the latency to eat in a novel environment compared to vehicle. UCM765 and MLT did not affect the total time and the number of entries into the central area of the OFT, but unlike DZ, did not impair locomotion. The anxiolytic effects of UCM765 and MLT in the EPMT and the NSFT were blocked using a pre-treatment with the MT(1)/MT(2) antagonist luzindole (10mg/kg) or the MT(2) antagonist 4P-PDOT (10mg/kg). These results demonstrated, for the first time, the anxiolytic properties of UCM765 and suggest that MT(2)-receptors may be considered a novel target for the development of anxiolytic drugs.

Patients with mental disorders are at an elevated risk for developing aggressive behavior. In the last 19 years, the psychopharmacological treatment of aggression has changed dramatically because of the introduction of atypical antipsychotics into the market and the increased use of anticonvulsants and lithium in the treatment of aggressive patients.Using a translational medicine approach, this review (part 1 of 2) examines the neurobiology of aggression, discussing the major neurotransmitter systems implicated in its pathogenesis, namely, serotonin, glutamate, norepinephrine, dopamine, and γ-aminobutyric acid, and also their respective receptors. The preclinical and clinical pharmacological studies concerning the role of these neurotransmitters have been reviewed, as well as research using transgenic animal models. The complex interaction among these neurotransmitters occurs at the level of brain areas and neural circuits such as the orbitoprefrontal cortex, anterior cortex, amygdala, hippocampus, periaqueductal gray, and septal nuclei, where the receptors of these neurotransmitters are expressed. The neurobiological mechanism of aggression is important to understand the rationale for using atypical antipsychotics, anticonvulsants, and lithium in treating aggressive behavior. Further research is necessary to establish how these neurotransmitter systems interact with brain circuits to control aggressive behavior at the intracellular level.

Melatonin activates two brain G-protein coupled receptors, MT1and MT2, whose differential roles in the sleep–wake cycle remain to be defined. The novel MT2receptor partial agonist,N-{2-[(3-methoxyphenyl) phenylamino] ethyl} acetamide (UCM765), is here shown to selectively promote non-rapid eye movement sleep (NREMS) in rats and mice. The enhancement of NREMS by UCM765 is nullified by the pharmacological blockade or genetic deletion of MT2receptors. MT2, but not MT1, knock-out mice show a decrease in NREMS compared to the wild strain. Immunohistochemical labeling reveals that MT2receptors are localized in sleep-related brain regions, and notably the reticular thalamic nucleus (Rt). Microinfusion of UCM765 in the Rt promotes NREMS, and its systemic administration induces an increase in firing and rhythmic burst activity of Rt neurons, which is blocked by the MT2antagonist 4-phenyl-2-propionamidotetralin. Since developing hypnotics that increase NREMS without altering sleep architecture remains a medical challenge, MT2receptors may represent a novel target for the treatment of sleep disorders.

The contents of protein and non-protein (free and protein-bound) tryptophan and of proteins in cocoa beans of various origin were determined. Protein concentrations varied from 11.8. g/100. g in beans from the Dominican Republic to 15.7. g/100. g in roasted beans from the Ivory Coast. The highest protein tryptophan content was found in cocoa beans from Ecuador. Madagascar beans had the highest value of free tryptophan and Echeandia the lowest (17.26 and 6.39. mg/100. g, respectively). Tryptophan was bound to water-soluble proteins as well as to proteins soluble in buffer solution (pH 8.9) and in 70% ethanol. In particular, Dominican Republic cocoa contained the highest amount of tryptophan bound to water-soluble proteins. Very little tryptophan was linked to proteins soluble in alkaline or ethanol solutions, and values ranged from 0.96 to 3.04 and from 0.24 to 1.21. mg/100. g of dry defatted cocoa sample, respectively. © 2010 Elsevier Ltd.

The water-soluble protein profile of the seeds of green, red, and yellow Theobroma cacao L. fruits has been determined by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-ToF-MS). The seeds were powdered under liquid nitrogen and defatted. The residues were dialyzed and lyophilized. The obtained samples were suspended in the matrix solution of sinapinic acid. The obtained MALDI mass spectra showed the presence of a wide number of proteins with molecular weight ranging from 8000 to 13 000 Da and a cluster of peaks centered at 21 000 Da that were attributed to albumin. The abundance of this peak was found to depend on the different portion of the seed (husk, apical and cortical parts); however, the MALDI mass spectra obtained from the different varieties of cocoa were practically superimposable. Changes in the protein profiles were also observed after the cocoa seeds were treated by fermentation and roasting, which are processes usually employed for the commercial production of cocoa.

The currently recommended therapy for chronic hepatitis C (HCV) is a combination of pegylated interferon-alpha (PEG-IFN alpha) and ribavirin. Psychiatric disorders, including depression, are frequent in HCV patients under therapy. We investigated the effect of the antiviral treatment on tryptophan (Trp) metabolism along both serotonin pathway (via 5-hydroxytryptophan, 5-HTP) and kynurenine (Kyn) pathway and on the onset of depressive symptoms in patients with HCV. The key enzyme of the Kyn pathway is indoleamine 2,3-dioxygenase (IDO), an intracellular haem protein enzyme expressed in several tissues. It was also investigated the influence of the therapy with PEG-IFN-alpha-2a or PEG-IFN-alpha-2b plus oral ribavirin and possible differences between genders. Free and total Trp, 5-hydroxytryptophan (5-HTP) and Kyn serum concentrations and the presence of depressive symptoms [Beck Depression Inventory (BDI) scores] were evaluated in 45 patients with HCV infection treated with PEG-IFN alpha-2a or -2b at four different times: baseline (before treatment), 1 and 6 months during therapy, and 3 months after the end of therapy. The concentration of serum total TRP (free + protein bound) as well as that of 5-HTP significantly decreased after 1 and 6 months of therapy, and then returned to baseline values 3 months after the end of therapy, while the levels of free TRP did not vary significantly during and after the therapy. On the contrary, the time course of Kyn markedly arose during treatment, paralleled by a significant increase of [Kyn/Trp] × 10 3 ratio, an index used to measure IDO activity. No significant difference was detected between males and females neither between PEG-IFN-alpha-2a or -2b treatment. The BDI scores significantly increased during therapy, and returned to baseline values 3 months after the end of therapy. Our results support the hypothesis that the increased IDO-mediated tryptophan metabolism along the Kyn pathway, leading to plasma Trp depletion and a decline of serotonin pathway, concurs to the development of depressive symptoms observed in HCV patients undergoing IFN-alpha therapy. © 2010 Elsevier Masson SAS. All rights reserved.

Centella asiatica (L.) Urban is widely used in traditional medicine in many countries and in the formulation of drugs and cosmetics, and is therefore suitable as a trade item for the development of medicinal plants for the population of Nepal. The aim of this work was to select plant populations of C. asiatica with high contents of secondary metabolites growing in various localities in Nepal, and to enhance knowledge of the cultivation of this plant. Quali-quantitative analysis of bioactive triterpenes (asiaticoside and asiatic acid) and phenol derivatives (flavonoids and caffeoyl esters) was performed by HPLC-DAD-ELSD. The highest quantities of triterpenes and phenols were found in samples from the Gorkha and Chitwan districts. Regarding cultivated plants, soil fertilisation is critical, since over-rich soils affect secondary metabolite content. Plants growing in sand-rich soils produce more terpenes. This work provides indications on how to select high-terpene producing germplasm and recommendations for plant cultivation.

The composition of the essential oil of Lindera neesiana Kurz fruit was examined by GC-MS, (1)H, (13)C and bidimensional NMR techniques (HMQC, HMBC, COSY, TOCSY). Forty compounds were identified, representing approximately 86% of the oil: Z-citral (15.08%), E-citral (11.89%), eucalyptol (8.75%), citronellal (6.72%), alpha-pinene (6.63%) and beta-pinene (5.61%) were the major components. The essential oil of L. neesiana fruit showed significant antimicrobial activity against Staphylococcus aureus and Candida albicans at non-cytotoxic doses in human keratinocytes, suggesting possible topical applications. GRAPHICAL ABSTRACT: The essential oil of Lindera neesiana was investigated by GC-MS and NMR techniques. Its biological activities suggest possible topical applications.

High-molecular-weight (HMW) coloured compounds called melanoidins are widely distributed, particularly in foods. It has been proposed that they originate through the Maillard reaction, a non-enzymatic browning reaction, due to the interaction between protein or peptide amino groups and carbohydrates. The melanoidin structure is not definitively known, and they have been generally defined as HMW nitrogen-containing brown polymers. In order to gain information on the nature of melanoidins, a simple in vitro model was chosen to investigate the products of the reactions between sugars and peptide/proteins. This approach would elucidate whether melanoidin formation is due to the binding of different sugar units to a peptide/protein or vice versa. With this aim, the reactivity of two different peptides, EPK177 and physalaemin, and a low-molecular-weight (LMW) protein, lysozyme, was tested towards different saccharides (glucose, maltotriose (MT), maltopentaose and dextran 1000) in aqueous solutions at differenttemperatures. The incubation mixtures were analysed at different reaction times by MALDI/MS. Furthermore, in order to verify the possible role of sugar pyrolysis products in melanoidin formation, the products arising from the thermal treatment at 200 degrees C of MT were incubated with lysozyme, and the reaction products were analysed by the same MS approach. The obtained results allowed the establishment of some general views: melanoidins cannot simply originate by reactions of sugar moieties with proteins. In fact, the reaction easily occurs, but it does not lead to any coloured product, as melanoidins have been described to be; melanoidins cannot originate from the thermal degradation products of glycated proteins. In fact, the thermal treatment of glycated lysozyme leads to a severe degradation of the protein with the formation of LMW species, far from the view of melanoidins as HMW compounds; experimental evidence has been gained on the melanoidin formation through reaction of intact protein with the pyrolysis products of MT. This hypothesis has been supported either from MALDI measurements or from spectroscopic data that show an absorption band in the range 300-600 nm, typical of melanoidins. Copyright (C) 2009 John Wiley & Sons, Ltd.

One new glycoside derivative from syringic acid and one new phenol glycoside, curculigoside E (1) and orchioside D (2), were isolated and characterized from the rootstock of Curculigo orchioides collected in the Nawalparasi District (Nepal). The structures of the new isolated compounds were elucidated by means of spectroscopic methods such as 1D, 2D NMR and MS.

In this paper we report the study of tryptophan metabolism via serotonin in ventricular CSF in HIV-1 infection in order to investigate the origin of tryptophan metabolites in the human brain. The patients (n=4) were affected with non-communicating hydrocephalus. One of these also was suffering from HIV-1 infection. The CSF was withdrawn from different sites of the cerebral cavity with a neuroendoscopic procedure which allows an accurate exploration of all the cerebral ventricles. The measurement of tryptophan, 5-hydroxytryptophan, serotonin, 5-hydroxyindoleacetic acid, and melatonin was carried out by HPLC with fluorometric detection. In HIV-1 infection the highest concentration of tryptophan is present in the CSF of the choroid plexus; however, the levels are markedly lower than those in hydrocephalic individuals (control group). 5-Hydroxytryptophan CSF content is higher in HIV-1 infection than in hydrocephalic controls in all districts examined. Regarding serotonin, a great difference appears in the choroid plexus and in the pituitary recess between the HIV-1 infected patient and the control group. The values of 5-hydroxyindoleacetic acid are much lower in the CSF of the HIV-1 infected patient than in hydrocephalic controls. Melatonin levels appear to fluctuate largely but, in the HIV-1 infection, a great variability is present among the sites of CSF withdrawal. The third ventricle contains the highest concentration of melatonin and the choroid plexus and the pituitary recess the lowest. All the melatonin concentrations in HIV-1 infection are largely different than in hydrocephalic controls. This is the first report on the measurement of tryptophan metabolites via serotonin in ventricular CSF in HIV-1 infection.

Cereals and legumes are the major source of protein in the human diet. There is little information on the presence of non-protein tryptophan, one of the essential amino acids less represented in the vegetable proteins. Our results show that tryptophan is present not only in the free-form but also is linked either to water soluble proteins or to proteins extracted at pH 8.9 both in cereal and legume flours. As regards the cereals, wheat and spelt contain the highest content of protein tryptophan and maize the lowest. Spelt, followed by barley and pearl millet flours, contains the highest amounts of free tryptophan and the rice the lowest. In addition, spelt flour shows the highest levels of tryptophan linked to both water soluble and buffered protein fractions, whereas rice contains the lowest amounts of protein-bound tryptophan. Among the legume flours, soybeans show the highest value in protein tryptophan and peas the lowest. Chick peas contain the highest concentrations of both free and protein-bound tryptophan water soluble fraction. This last fraction appears absent in broad bean, lentil and soybean flours. In addition, beans are shown to contain the highest levels of tryptophan linked to proteins extracted at pH 8.9, and peanuts the lowest values both as free and protein-bound forms. Considering that tryptophan is one of the limiting amino acids of the biological value of vegetable proteins, the determination of non-protein tryptophan in food is very useful in calculating the score.

The role of melatonin in humans still remains unclear. Uncertainties persist about its effects on neurophysiology regarding its levels in human cerebrospinal fluid (CSF), as the bulk of knowledge on this subject mainly derives from studies conducted on animals. In this study, CSF was micro-sampled with a simple, new method from each cerebral ventricle of patients undergoing neuroendoscopy for hydrocephalus. Our purpose was to measure CSF melatonin levels and determine possible differences in its concentration among various significant areas in the cerebral ventricles (e.g. pineal recess, pituitary recess, lateral ventricle, fourth ventricle) and lumbar cistern. From 2002 to 2004, 10 hydrocephalic patients were operated on using a neuroendoscopic technique. The CSF specimens were investigated for melatonin concentrations (free plus protein-bound) after deproteinization; the measurement technique was high-performance liquid chromatography. The preliminary data obtained with this endoscopic micro-sampling technique (applied to humans for the first time) suggest that melatonin is more concentrated within the ventricles and its highest concentration is found in the third ventricle (IIIv), although the difference detected between the CSF of the IIIv and that of the pineal recess was not significant.

Tryptophan, the serotonin (5-HT) precursor, is circulating in blood in both free (FT) and protein-bound forms. The free form crosses the hematoencephalic barrier and is converted into 5-HT. During the fertile years, tryptophan levels are negatively correlated to gonadotropin concentrations. The present study aims to evaluate the correlation between circulating tryptophan, gonadotropin and estradiol (E2) levels postmenopause.Serum levels of total tryptophan (TT, free + protein-bound) and FT, and plasma luteinizing hormone (LH), follicle stimulating hormone (FSH), and E2 were determined in 15 postmenopausal women and 15 cycling women during follicular (days 7-10), periovulatory (days 13-16) and luteal (days 21-24) phases of the menstrual cycle. Data were analyzed by ANOVA, linear correlation coefficients and hierarchical cluster analysis of variables.TT, but not FT, levels were significantly (p0.05) higher in postmenopausal (12.07+/-0.40 microg/ml) than fertile women in the periovulatory period (10.46+/-0.36 microg/ml). In postmenopausal women, there was no significant correlation between TT and FT, nor between these tryptophan forms and gonadotropins, but only between FT and E2. Cluster analysis showed that the main cluster composed by FSH-LH-TT-FT observed in fertile women was absent in postmenopause, since both serum tryptophan forms were distant from gonadotropins.High TT levels circulate in postmenopausal women, with lack of correlation between TT and FT, and FT/TT and gonadotropins. Since estrogens play a pivotal role on central 5-HT metabolism, estrogen deprivation may alter the brain tryptophan utilization for 5-HT synthesis and its relation to gonadotropin release.

The content of proteic and nonproteic (free and protein-bound) tryptophan and of proteins in quinoa, wheat, rice, maize, barley, oat, rye, spelt, sorghum and millet flours was determined. Protein content and proteic tryptophan of quinoa were similar to that of wheat and spelt, but higher than in other cereals. Free tryptophan in quinoa flour showed values similar to those of wheat, oat and sorghum Kalblank, lower than those of barley, spelt and pearl millet, but higher than in rice, maize, rye, sorghum DK 34 – Alabama hybrid. In addition, nonproteic tryptophan appears bound both to water soluble proteins and to proteins soluble at pH 8.9. The results are discussed regarding the importance of the nonprotein tryptophan fraction, the only one able to enter the brain, that is more easily absorbed, so guarantees a greater amount available for uptake by the central nervous system.

Background: Melancholic depression, described also as endogenous depression, is a mood disorder with distinctive specific psychopathological features and biological homogeneity, including anhedonia, circadian variation of mood, psychomotor activation, weight loss, diurnal cortisol changes, and sleep disturbances. Although several hypotheses have been proposed, the etiology of this disorder is still unknown. Methods: Behavioral, electrophysiological and biochemical approaches were used to characterize the emotional phenotype, serotonergic and noradrenergic electrical activity, and corticosterone in melatonin MT1 receptor knockout mice and their wild type counterparts, during both light and dark phases. Results: Melatonin MT1 receptor knockout mice have decreased mobility in the forced swim and tail suspension tests as well as decreased sucrose consumption, mostly during the dark/inactive phase. These mood variations are reversed by chronic treatment with the tricyclic antidepressant desipramine. In addition, MT1 receptor knockout mice exhibit psychomotor disturbances, higher serum levels of corticosterone the dark phase, and a blunted circadian variation of corticosterone levels. In vivo electrophysiological recordings show a decreased burst-firing activity of locus coeruleus norepinephrine neurons during the dark phase. The circadian physiological variation in the spontaneous firing activity of high-firing neuronal subpopulations of both norepinephrine neurons and dorsal raphe serotonin neurons are abolished in MT1 knockout mice. Conclusions: These data demonstrate that melatonin MT1 receptor knockout mice recapitulate several behavioral and neurobiological circadian changes of human melancholic depression and, for the first time, suggest that the MT1 receptor may be implicated in the pathogenesis of melancholic depression and is a potential pharmacological target for this mental condition.

The activity of tyrosinase and peroxidase +H(2)O(2) in promoting melanogenesis from tryptophan (Trp) and 7-hydroxytryptophan (7-HTP) has been investigated. The reaction samples have been drawn at different reaction times and analysed by MALDI mass spectrometry.The data obtained showed that tryptophan undergoes, under tyrosinase and peroxidase action, an oligomerization process mainly due to the reaction of anthranilic acid (AA) and Trp. However, analysing the UV and fluorescence data, it is seen that the oligomers cannot belong to the melanin pattern, but their possible role in melanogenesis is not to be excluded. Once it reacts with the two enzymes, 7-hydroxytryptophan leads to dark brown products, indicating its possible role in melanin production. In contrast to what was observed in the case of 5-hydroxytryptophan, for which oligomers were constituted by 5-hydroxytryptophan (5-HTP) and 5-hydroxytryptamine (5-HT) units, the MALDI data indicate a sharply different behaviour for 7-HTP. In fact, in the case of 5-hydroxytryptophan, oligomerization takes place through the formation of 5-hydroxytryptamine and the oligomerization products are due to mixed 5-HTP-5-HT oligomers. In the case of 7-hydroxytryptophan, the formation of 7-hydroxytryptamine (7-HT) is also observed, but it does not seem to play any role; the only oligomerization products formed are due to the reaction of 7-hydroxytryptophan and AA. The data so obtained indicate that 7-hydroxytryptophan acts like an effective melanin precursor in the presence of both tyrosinase and peroxidase +H(2)O(2).

The aim of this study was to investigate in vitro the variations with age of the activities of the two antioxidant enzymes Cu/Zn-superoxide dismutase (SOD) and indole 2,3-dioxygenase (IDO) in metabolically active tissues of rats of various ages. In rats aged one week and 2-3 months the highest Cu/Zn-SOD activity was found in the liver and the lowest in the small intestine. At 12 and 18 months of age, the activity was higher in the brain and kidneys, when compared to the small intestine, lungs and liver. Cu/Zn-SOD activity decreased significantly after 2-3 months of age with advancing age in all tissues examined. In newborn rats IDO activity was present only in the small intestine. In the group of rats aged 2-3 months, the highest specific activity was observed in the small intestine and the lowest in the lungs and kidneys, whereas at 12 months of age, the highest IDO activity was found in the brain, with kidneys presenting the lowest activity. At 18 months, IDO returned to be more elevated in the small intestine. At 12 months of age the values of IDO in the tissues varied slightly, while at 18 months similar activities were found between the lungs and brain and between the small intestine and kidneys. In relation to age, IDO specific activity declined in the small intestine, after 2-3 months of age. In the lungs, the activity remained unchanged; in the brain and in the kidneys activity decreased significantly from 2-3 to 18 months of age. In conclusion, this study demonstrates an age-related decline in Cu/Zn-SOD and IDO activities, the two enzymes responsible for scavenging O2*-.

By a recent minimally invasive neuroendoscopic technique, the cerebral ventricles have been reached in a quick, reliable, and harmless way, making possible the study of cerebrospinal fluid (CSF) of the lateral ventricles and, above all, the CSF adjacent to the walls of the third ventricle. Tryptophan, 5-hydroxytryptophan, serotonin (5-HT), and 5-hydroxyindoleacetic acid (5-HIAA) were measured in CSF by HPLC equipment. Twenty-six patients affected with noncommunicating hydrocephalus were enrolled in the study and, as controls, 28 subjects not suffering from any neurological disease. The concentrations of tryptophan were higher in right ventricular CSF than in lumbar CSF (P < 0.01). 5-HT was detectable in the CSF of the right ventricle of hydrocephalic patients. 5-HIAA was higher in right ventricular CSF than in cisternal and lumbar CSF (P < 0.01), both in controls and in hydrocephalic patients. However, there was a higher concentration of 5-HIAA in right ventricular (P < 0.05) and cisternal (P < 0.01) CSF in hydrocephalic patients in comparison with controls. In the CSF samples withdrawn during neuroendoscopy, 5-HT presented the highest concentrations in the pineal recess. The highest amounts of 5-HIAA were found in the choroid plexus, third and right ventricles, pituitary recess, and aqueduct, and the lowest in pineal recess, subarachnoid space, infundibulum, and interpeduncolar cistern. These results provide new insight into the fate of tryptophan and its metabolites via serotonin in the CSF and suggest the feasibility of the new neuroendoscopic technique for brain metabolic studies. © 2006 Wiley-Liss, Inc.

Since alterations of tryptophan metabolism have been reported in diabetes and atherosclerosis, it was thought of interest to investigate any role of cloricromene through the influence on the oxidative metabolism of the amino acid by using diabetic/hyperlipidemic rabbits. Male 4-month-old New Zealand white rabbits, fed a diet enriched with 1% cholesterol and 10% corn oil, were made diabetic with alloxan. During the hyperlipidemic diet, a group of rabbits was treated with cloricromene (10 mg/kg/day subcutaneously plus 1.5 mg/kg/day intravenously, for 5 weeks). The other group received saline. Normometabolic New Zealand rabbits fed standard diet, treated or not with cloricromene, were used as control. The specific activities of liver tryptophan 2,3-dioxygenase and small intestine indole 2,3-dioxygenase were not significantly changed by the drug treatment. Also the specific activities of other enzymes of the kynurenine pathway in the liver and kidneys, specifically kynurenine 3-monooxygenase, kynureninase and kynurenine-oxoglutarate transaminase, did not show any significant difference in both tissues between the two groups of rabbits. On the contrary, 3-hydroxyanthranilate 3,4-dioxygenase activity in the liver of diabetic/hyperlipidemic rabbits and control rabbits treated with cloricromene showed a slight increase in comparison with untreated animals. Conversely, the specific activity of the enzyme in kidneys was not affected by the drug treatment in diabetic/hyperlipidemic animals but was reduced in controls. Aminocarboxymuconate-semialdehyde decarboxylase specific activity remained unchanged in the liver following cloricromene treatment, instead the specific activity of the enzyme in the kidneys of the diabetic/hyperlipidemic rabbits was significantly increased by the drug, with a value more than double in comparison to untreated animals. The activity of the scavenger enzyme Cu/Zn superoxide dismutase (Cu/Zn SOD) in the small intestine was also determined and found significantly increased of about twice as much in the group of diabetic/hyperlipidemic rabbits treated with cloricromene. In conclusion, in diabetic/hyperlipidemic rabbits, cloricromene appeared to influence the enzymes involved in the last steps of tryptophan oxidative metabolism through the kynurenine pathway. This, together with the antioxidant action through the activation of Cu/Zn SOD, might deserve further investigation for evaluating any link between the observed experimental findings at the level of the kynurenine pathway and the clinical effect of the drug.

Neuroendoscopy has achieved extensive acceptance among neurosurgeons as a minimally invasive technique for the treatment of patients affected by blocked hydrocephalus. During endoscopic procedures minimal CSF amounts from selected anatomic sites of the ventricles can be withdrawn. Steerable endoscopes are used and their flexibility facilitates the aspiration of CSF during the preliminary inspection through the ventricular cavities, without any interference with the surgical actions or additional risks for the patients. In this preliminary study the concentrations of melatonin and other related metabolites in the lateral ventricles, third ventricle, pineal recess and infundibular recess were examined. The data obtained from a patient affected by blocked hydrocephalus confirmed a constant and significant difference of concentration of these substances, for instance, melatonin levels were found to be much higher in the third ventricle (542 pg/mL in its centre) than in the lateral ventricle (172 pg/mL in the right ventricle). Nevertheless, instead of what we would expect, the highest melatonin concentrations were not found in the pineal recess (438 pg/mL). In the future, neuroendoscopy, beside its evident therapeutic efficacy, could open new perspectives in the study of both CSF biochemistry and physiology, allowing a highly selective approach to the various substances which are released and float in it.

Background Quinolinic acid and other kynurenine metabolites of the oxidative metabolism of tryptophan play an important role in several pathophysiological conditions. We aimed to study the effect of age on the enzyme activities of tryptophan metabolism along the kynurenine pathway. Methods Enzyme activity was investigated in liver, kidneys and small intestine obtained from Sprague–Dawley rats of various ages (1 week, 2–3, 12 and 18 months). Results We found age-related differences in the liver tryptophan 2,3-dioxygenase, small intestine indole 2,3-dioxygenase, liver and kidney kynurenine 3-monooxygenase activities, which decreased significantly with age. Also liver kynureninase activity declined with age, while the activity in kidneys did not show an evident age-related pattern from 2–3 months to 18 months of age. Liver kynurenine oxoglutarate transaminase was quite similar through all considered age groups, while the activity in kidneys was significantly lower in newborn rats and progressively increased up to 12 months, then significantly decreased at 18 months of age. Liver and kidney 3-hydroxyanthranilate 3,4-dioxygenase progressively and significantly increased from newborns to 12 months of age; in the group of rats aged 18 months, the enzyme activity tended to diminish, although not significantly. The liver aminocarboxymuconate-semialdehyde decarboxylase activity increased up to 12 months of age, then tended to decrease at 18 months, while in the kidneys, in which the activity was higher than in the liver at all the considered ages, the activity remained constantly elevated from 2–3 months to 18 months of age. Conclusions A progressive decline in the enzyme activities involved in tryptophan metabolism along the kynurenine pathway in rat tissues was found with age, except for aminocarboxymuconate-semialdehyde decarboxylase, which, on the contrary, was increased after 2–3 months to the other older groups of age. The altered metabolism of tryptophan with ageing can lead to a decreased biosynthesis of nicotinic acid, tryptophan being the major source of body stores of NAD coenzymes, which are involved in almost all biogenetic and biosynthetic pathways of the organism.

Background The activity of nicotinic acid in hypercholesterolemia has been poorly understood. In man, nicotinic acid derives for the most part from tryptophan along the tryptophan–nicotinic acid pathway, also called the kynurenine pathway, kynurenine being the key metabolite in this process. In the present paper, we investigated if, in animals with hypercolesterolemia, degradation of tryptophan to nicotinic acid along the kynurenine pathway was perturbated. Methods Liver, kidney and intestine enzyme activities of the tryptophan–nicotinic acid pathway in normolipidemic, diet-induced hyperlipidemic New Zealand and heritable hypercholesterolemic Watanabe (WHHL) rabbits were determined. Results Liver tryptophan 2,3-dioxygenase (TDO) activity was present only as a holoenzyme and was higher in the controls than in the hyperlipidemic and Watanabe rabbits, but no difference was present between the group fed an atherogenic hyperlipidic diet and the WHHL rabbits. Small intestine indole 2,3-dioxygenase (IDO) did not vary significantly among the three groups but was higher in comparison with liver TDO activity. In liver, kynurenine 3-monooxygenase and kynurenine-oxoglutarate transaminase activities did not show any significant difference among the three groups of rabbits. Kynureninase and 3-hydroxyanthranilate 3,4-dioxygenase activities per g of fresh tissue decreased significantly in the group of hyperlipidemic and in WHHL rabbits. In the kidneys, kynurenine 3-monooxygenase and kynureninase activity did not change significantly in the three groups of rabbits; kynurenine-oxoglutarate transaminase activity per g of fresh tissue decreased in both hyperlipidemic groups, but no significant difference was observed between hyperlipidemic and Watanabe rabbits. 3-Hydroxyanthranilate 3,4-dioxygenase activity in kidney was decreased markedly in hyperlipidemic and Watanabe rabbits, but there was no difference between the two hypercholesterolemic groups. Aminocarboxymuconate-semialdehyde decarboxylase activity did not change. Thus 3-hydroxyanthranilate 3,4-dioxygenase may be an important regulatory mechanism in the control of the flow of tryptophan along the kynurenine pathway to NAD in hypercholesterolemic rabbits. Conclusions This study first demonstrates that in rabbits, hypercholesterolemia, both diet- or genetically induced, can influence the enzyme activities of the tryptophan–nicotinic acid pathway leading to a decreased formation of nicotinic acid, and thus NAD.

Serum levels of tryptophan (Tip) and 5-hydroxytryptophan (5-HTP) were measured in the mother at birth, by normal delivery or cesarean section, on days 1 and 3 postpartum, and in the cord blood of the fetus-newborns. Decreases in Trp and 5-HIP levels during delivery were noted. Conversely, Trp levels in the cord blood of fetus-newborns were significantly higher than those of their mothers, and 5-HTP levels also showed a tendency to increase, whereas on day 1 post-partum Trp values were lower than those in fetal cord, but higher than those during spontaneous delivery. On day 3 post-partum, serum Trp levels were higher than those during spontaneous delivery, but similar to those on day 1. 5-HTP values tended to decrease with respect to those of day 1.Serum Trp and 5-HTP concentrations decreased significantly on day 1 post-partum after cesarean section, but increased on day 3, demonstrating that maternal Trp was being consumed during delivery. A major release of prolactin in serum on days 1 and 3 post-partum there was in women with normal delivery, revealing a correlation between Trp and prolactin in the first few days after birth, in relation to different conditions of delivery

Bipolar (BD) and major depression (MDD) disorders are severe mental illnesses characterised by altered levels of immune/inflammatory markers and disrupted white matter (WM) microstructure. A pro-inflammatory state was suggested to activate indoleamine 2,3-dioxygenase which, in turn, increases the amount of tryptophan (Trp) converted into kynurenine (Kyn). We investigated whether plasma levels of Trp, Kyn and Kyn/Trp ratio are associated with peripheral levels of immune/inflammatory markers and whether they are related to WM integrity in 100 MDD and 66 BD patients. Patients also underwent MRI, and fractional anisotropy (FA) was estimated as a measure of WM microstructure. BD patients showed higher Kyn levels and Kyn/Trp ratio than MDD patients, and lower FA in several WM tracts, including the corpus callosum and the inferior fronto-occipital fasciculus (IFO). Lower Trp levels associated with a more severe depressive symptomatology irrespective of diagnosis and with lower FA in the corpus callosum (CC) and external capsule (EC). We found an association of immune/inflammatory markers with Kyn/Trp ratio selectively in BD patients: IL-1β and TNF-α showed a positive relationship and IL-2 and IL-9 a negative relationship; in addition, higher IL-4 correlated with lower Kyn levels; higher Kyn/Trp ratio and IL-1β correlated with lower FA in the CC and IFO. Notably, the detrimental effect of IL-1β on the IFO was moderated by the Kyn/Trp ratio. These data suggest that in BD, cytokines and the conversion of Trp into Kyn may affect WM microstructure and support the idea that distinct mechanisms underlie the pathophysiology of BD and MDD.