Structural basis of the mutagenicity of heterocyclic amines formed during the cooking processes

A data base consisting of 61 heterocyclic amines formed during food preparation and their desamino analogs were subjected to structure-activity analysis using the CASE method, a structural activity relational expert system. The program identified the major structural determinants associated with mutagenic activity or lack thereof. The structures identified as contributing to the probability of activity as well as those associated with mutagenic potency were highly predictive of molecules not in the learning set. The major structural determinant, the aromatic amino moiety, and quantum mechanical calculations revealed that the mutagenic potency associated with this functionality derived from their contribution to the energy of the Lowest Unoccupied Molecular Orbital (LUMO.) © 1993 Wiley-Liss, Inc.     

Determination of meta- and para-hydroxyphenylacetic acid levels in single caudate nuclei by selected metastable peak monitoring: a new sensitive gas chromatographic-mass spectrometric procedure

The levels of meta- and para-hydroxyphenylacetic acids in rat brain caudate nuclei have been determined by a new gas chromatography-mass spectrometric (GC-MS) procedure in which metastable transitions specific to the derivatized acids are observed. The method is more sensitive than previous procedures and allows determination of the acid concentrations using single caudate nuclei. The levels of the meta- and para-isomers were found to be 9.2 ± 1.5 and 43 ± 3.7 ng/g, respectively.     

Determination of Biogenous Amines in Fungus-Cultures (Candida albicans,Trichophyton mentagrophytes,Trichophyton rubrum and Microsporum canis) by Thin-Layer Chromatography and Mass-Spectrometry*

Summary: The biogenous amines methylamine, dimethylamine, ethylamine, ethanol-amine, piperidine, β-phenylethylamine, serotonine, pyridoxamine, hordenine, ammonia, isoamylamine, spermine and spermidine were qualitatively detected, and dimethylamine, ethanolamine, piperidine, β-phenylethylamine, serotonine and pyridoxamine and hodenine were quantitatively determined using two-dimensional thin-layer chromatography in Trichophyton mentagrophytes, Trichophyton rubrum, Microsporum canis and Candida albicans treated with DANS, according to Seiler and Wiechmann's method. However, no methylamine was detected in Microsporum canis and no ethylamine in Candida albicans. The presence of a certain amine was established on the strength of identity of reference values, of colour spots and knowledge of the chemical transformation undergone. For quantitative analysis, the spectro-fluorometric reading of the DANS amide extracted from the silica-gel was used. The amine content varied between 10^-8 and 10^-11 moles per gram of fungus-culture for each amine and fungus-culture investigated. For each amine, the quantitiy present lay within a range of a power of ten. Only serotonine in Candida albicans was a power of ten higher than the rest. Histamine could not be detected. To confirm these results, the presence of serotonine, ethanolamine and piperidine in Candida albicans and the absence of histamine were investigated by identifying the amines as their t-dimethylamino-naphthaline-5-sulphonyl derivatives using-mass-spec-troscopy. The results confirmed the thin-layer chromatography results. Again, no histamine was detected. Zusammenfassung: Die biogenen Amine Methylamin, Dimethylamin, Äthylamin, Äthanolamin, Properdin, β-Phenäthylamin, Serotonin, Pyridoxamin, Hordenin, Ammoniak, Isoamylamin, Spermin und Spermidin wurden qualitativ, Dimethylamin, Äthanolamin, Piperdin, β-Phenäthylamin, Serotonin, Pyridoxamin und Hordenin quantitativ mittels zweidimensionaler Dünnschichtchromatographie nach Umsetzung mit 1-Dimethylamino-naphthalin-5-sulfonyl nach der Methode Seiler und Wiechmann inin Trichophyton mentagrophytes, Trichophyton rubrum, Microsporum canis und Candida albicans – mit Ausnahme von Methylamin bei Microsporum canis und Äthylamin bei Candida albicans – nachgewiesen. Identität der Rf-Werte, Fluorescenzfarbe und der Weg der Aufbereitung lassen die Annahme des Vorkommens der ge-nannten Amine zu. Zur quantitativen Analyse wurde die spektro-fluorimetrische Messung der aus Kiesel-gel eluierten DANS-Amide verwandt. Der Amingehalt bewegte sich zwischen 10^-8 bis 10^-11 Mol pro 1 Gramm Pilzkultur je nach Amin und untersuchter Pilzkultur. Der jeweilige Amingehalt lag bei den vier Pilzkulturen innerhalb einer Zehner-potenz; lediglich Serotonin war bei Candida albicans um eine Zehnerpotens höher. Histamin konnte nicht nachgewiesen werden. Um diese Ergebnisse zu sichern wurde das Vorhandensein von Serotonin, Äthanol-amin und Piperidin in Candida albicans und das Fehlen von Histamin durch massen-spektrometrische Identifizierung in Form ihrer DANS-Derivate untersucht. Die dünnschichtchromatrographischen Ergebnisse konnten massenspektrometrisch be-stätigt werden. Audi hierbei war Histamin nicht nachzuweisen.     

Relationship between cerebrospinal fluid amine metabolites, neuroendocrine findings and personality dimensions (Marke-Nyman scale factors) in psychiatric patients

5-Hydroxyindoleacetic acid (5-HIAA) and homovanillic acid (HVA) were measured in the spinal fluid of 45 women hospitalized in a psychiatric department for major depression (14 cases), schizophrenia (18 cases) and alcohol dependence (13 cases). Dexamethasone suppression tests were performed following CSF examinations in all patients, and TRH stimulation tests were also made in six subjects. All biological examinations were carried out in a drug-free state. The Marke-Nyman Temperament scale was administered to all patients as soon as severe psychotic disturbances subsided and sufficient cooperation was achieved, but no later than 10 days following biological examinations. The MNT was repeated after recovery to check reliability of the test results during an episode of a psychiatric disorder. CSF amine metabolite concentrations did not differ significantly in the three patient groups; postdexamethasone average cortisol levels were above the critical level (5 micrograms/dl) in each group, the highest values being found in major depression. One of the three MNT factors was inhomogeneous among diagnostic groups (validity: low in depression and alcoholism), but the other two also differed from a healthy control population. Correlation structure between biological and psychological variables was homogeneous throughout the diagnoses and a significant inverse correlation was found only between CSF 5-HIAA and the validity factor of MNT. Maximal TSH response to TRH stimulation correlated with both solidity and stability in the MNT scale. Since MNT results proved to be stable even during an illness episode, a possible link is suggested between personality traits and central serotonin metabolism.     

Electron microscopic cytochemical correlates of histofluorescence

The biogenic amines, norepinephrine and dopamine, have been localized electron microscopically in the substantia nigra, pineal body, adrenal medulla and stellate ganglion of squirrel monkeys. The method of localization has been by the use of a specific cytochemical technique, utilizing a chromium (Cr) complex with an isoquiniline derivative formed by the reaction of the unsubstituted biogenic amine with glutaraldehyde. The final reaction product, i.e., amine-glutaraldehyde-Cr, has been identified using energy dispersive X-ray analysis and the positive Cr reactive sites have been correlated with light microscopy conducted by using glyoxylic acid histofluorence. All tissues were taken from squirrel monkeys which had either been perfused with the fixative or had been perfused with an F-12 buffer prior to fixation and/or histochemical treatment. The best results were obtained from the F-12 perfusion followed by tissue being taken through the various histochemical-cytochemical procedures. The electron microscopic localization of deposits shows significantly large structures containing the Cr positive amine material. These large deposits have not heretofore been described and correlate well in size and location with what is seen with histofluorescence. This electron microscopic technique should lead to further advances in the study of biogenic amines in nervous tissue when fine structural localization, plus well preserved morphology, are essential.     

A role for biogenic amines in developmental language disorders

The authors discuss the current uncertainty regarding etiology, treatment, and classification of developmental language disorders (DLD). Referring to previous reports in the literature, they propose a specific subclass of DLD associated with a hypothesized dysfunction of the dopaminergic system of the basal ganglia. Mechanisms of dysfunction and treatment implications are discussed.     

Characterization of the adrenergic activity of arbutamine, a novel agent for pharmacological stress testing

In this study, we characterized the interactions of arbutamine, a novel catecholamine developed for use as a cardiac stress testing agent, with different adrenergic receptor subtypes in vitro. These effects were compared with those of isoproterenol. In the electrically stimulated left atria of rats, arbutamine increased contractile force. The pD₂ values (-log of the dose that produces 50% of the maximal responses) for arbutamine and isoproterenol were 8.45±0.15 and 8.55±0.02, respectively. Metoprolol shifted the concentration-effect curves for both isoproterenol and arbutamine to the right with a pA₂ value (-log of the dose of the antagonist that reduces the maximal responses of an agonist to 50%) of 7.22–7.5. Both arbutamine and isoproterenol increased the rate of spontaneously beating rat right atria with pD₂ values of 9.0±0.19 and 8.82±0.18, respectively. The affinity constants (K_A) of arbutamine and isoproterenol for cardiac beta₁-adrenergic receptors, as determined by competition binding assays, were found to be 7.32 and 6.04, respectively. In guinea pig trachea, arbutamine and isoproterenol produced a concentration-dependent relaxation that was blocked by propranolol. Their pD₂ values were 7.9±0.1 and 8.2±0.1, respectively. Arbutamine contracted isolated rat aortic rings with a maximal increase of 38.1±6.7% that of 10 μM of norepinephrine. In rat white adipocytes, arbutamine, isoproterenol, and BRL-37344 stimulated glycerol release, with the order of potency being BRL-37344 > arbutamine > isoproterenol. In hamster brown adipocytes, the order was arbutamine > isoproterenol > BRL-37344. Moreover, arbutamine stimulated beta₃-adrenergic receptors in guinea pig ileum. In conclusion, arbutamine is a novel catecholamine with similar potency and efficacy to that of isoproterenol. It stimulates cardiac beta₁-, tracheal beta₂-, and adiopocyte beta₃-adrenergic receptors. Arbutamine does not stimulate alpha-adrenergic receptors at concentrations that wer high enough to maximally activate the beta-adrenergic receptors.     

Deficits in inhibitory avoidance after neurotoxic lesions of the ventral striatum are neurochemically and behaviorally selective

Inhibitory avoidance (step-in type) was investigated in rats subjected to neurochemical lesions of the ventral striatum. The neurotoxins 6-hydroxydopamine or 5,7-dihydroxytryptamine were used to produce selective depletions of either dopamine, norepinephrine or serotonin. Only lesions which decreased the dopamine content of the ventral striatum impaired post-shock step-in behavior. Measurement of footshock reactivity by the Flinch-Jump technique indicated that only serotonin depletion altered reactivity to footshocks. Assessment of open-field locomotor behavior showed that the dopamine-denervated rats were hypoactive (fewer rearings) compared to controls, whereas serotonin-depleted rats were hyperactive. It is concluded that the deficit in inhibitory avoidance behavior following ventral striatal dopamine loss was dissociated from its effect on locomotor activity.     

Characterization of the urinary metabolites of 5-amino-1-naphthol in the rat

The metabolic fate of [¹⁴C]5-amino-1-naphthol (5A1N) was investigated in Sprague-Dawley rats. [¹⁴C]5A1N was administered by gastric intubation to male rats at doses 1, 37 and 135 mg/kg body weight. In a separate experiment the rats were also dosed with 150 mg/kg of unlabeled 5A1N daily for 4 consecutive days. Between 74% and 85% of the administered dose was excreted in the urine. Over 98% of the urinary radioactivity was characterized as unchanged 5A1N, 5-acetamido-1-naphthol (5AA1N) and glucuronic and sulfuric acid conjugates of both 5A1N and 5AA1N. Unchanged 5A1N and 5AA1N accounted for less than 3% of the dose. The amount of 5A1N converted to 5AA1N and its conjugates varied inversely with the dose. Two minor metabolites were not identified. Rats dosed repeatedly with 150 mg/kg of 5A1N showed no significant change in metabolite excretion patterns compared to rats dosed singly. These findings indicate that in the rodent model the metabolism of 5A1N was dose dependent, and occurred predominantly by phase II reaction involving N-acetylation and conjugation with glucuronic and sulfuric acids. N-Acetylation predominated at lower doses and O-sulfate conjugation at higher doses. There was no evidence for the formation of N-hydroxylated metabolites over the dose range studied.