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Problems in the development of radioimmunoassay of catecholamines.

This review describes experiments to produce antibodies towards the catecholamines and some catecholamine metabolites with the intention of developing radioimmunological methods. First, attempts to produce antibodies to the catecholamines themselves are described. In the course of synthesis of immunogens of catecholamines, it was necessary to exercise special care - e.g. the introduction of protecting groups - owing to the great susceptibility of the catechol structure to oxidation. Despite many efforts, only one working group (Miwa et al.) has reported in a series of papers the successful production of antibodies to catecholamines, but they did not develop a radioimmunoassay. In contrast, antibodies to some metabolites of the catecholamines - such as 3,4-dimethoxyphenylethylamine, the 3-O-methylated catecholamines (normetanephrine, metaneprine, and 3-methoxytyramine) as well as 3-methoxy-4-hydroxyphenylethyleneglycol - have been produced, whose avidity and specificity were high enough to permit the development of sensitive radioimmunoassays.

Antibody Specificity↗

[Excretion of 3,4-dimethoxy phenylethylamine in the urine of schizophrenics].

According to the hypothesis of Osmond, Harley-Mason and Smythies on abnormal methylation products in the catecholamine metabolism in schizophrenics, the excretion of 3,4-dimethoxyphenylethylamine (3,4-DMPEA) in the urine was examined in 80 patients with endogenous psychoses and in 20 normal persons. In 38% of the patients 3,4-DMPEA was found, whereas no 3,4-DMPEA was found in normal persons. When the biochemical findings obtained are correlated to the corresponding diagnoses the highest incidence of positive findings was observed in paranoid-hallucinatory schizophrenics with 71% in males and 75% in females. The signification of controls during the course of the experiments is emphasized.

Adolescent↗

Severe aggression in rats induced by mescaline but not other hallucinogens.

Pairs of male Sprague-Dawley rats were administered mescaline, lysergic acid diethylamide (LSD), psilocin, N,N-dimethyltryptamine (DMT), 3,4-dimethoxyphenylethylamine (DMPEA), or 5-hydroxydopamine (5-OHDA) IP prior to being placed in a shock-elicited aggression situation. When foot shock was delivered, controls struck each other with their forepaws, but never engaged in either biting or injurious fighting. Mescaline-treated rats (50 or 250 mg) rarely struck each other, but engaged in nearly lethal biting. While LSD (25--400 micrograms/kg), psilocin (2.0 mg/kg), and DMT (5 mg/kg) produced some biting, this did not significantly differ from controls and never resulted in injuries. At higher doses, psilocin, DMT, and DMPEA decreased the amount and intensity of fighting. Rats treated with 5-OHDA (8--200 mg/kg) or LSD (25--400 micrograms/kg) did not differ from controls. These results suggest that mescaline's ability to induce pathological aggression in rats exposed to foot shock is not shared by other hallucinogens or nonhallucinogenic mescaline analogues.

Aggression↗

Fluorometric determination of DL-fenfluramine, DL-norfenfluramine and phentermine in plasma by achiral and chiral high-performance liquid chromatography.

High-performance liquid chromatography (HPLC) with fluorescence detection has been developed for the simultaneous determination of sympathomimetic amines including ephedrine, norephedrine, 2-phenylethylamine, 4-bromo-2,5-dimethoxyphenylethylamine, phentermine (Phen) and DL-fenfluramine (Fen) in spiked human plasma. Furthermore, an enantioselective HPLC method for the separation of D-Fen (dexfenfluramine) and L-Fen (levofenfluramine) in addition to their active metabolites D- and L-norfenfluramine (Norf) is described. The detection was achieved at emission wavelength of 430 nm with excitation wavelength of 325 nm for both methods. The analytes were extracted from plasma (100 microl) at pH 10.6 with ethyl acetate using fluoxetine as the internal standard. The extracts were evaporated and derivatized with the fluorescence reagent 4-(4,5-diphenyl-1H-imidazole-2-yl)benzoyl chloride in the presence of carbonate buffer (pH 9.0). A gradient separation was achieved on a C18 column for the achiral separation or on a Chiralcel OD-R column for the chiral separation. The methods were fully validated, and shown to have excellent linearity, sensitivity and precision. The chiral method has been applied for the determination of D- and L-enantiomers of Fen and Norf, in addition to Phen in rat plasma after an intraperitoneal administration of DL-Fen and Phen, simultaneously.

Animals↗

Synthesis and body distribution of several iodine-131 labeled centrally acting drugs.

1-(4-iodo-2,5-dimethoxyphenyl)-2-aminopropane (3B), 4-iodo-2,5-dimethoxyphenylethylamine (3A), and 1-(4-iodo-2,5, dimethoxyhenyl)-2-aminobutane (3C) have been synthesized with 131I. Labeled iodine monochloride reacts with the appropriately substituted phthalimide at the aromatic 4 position, and the phthalic acid group is removed with hydrazine. Body distribution was measured in rats; the most prominent difference between the three compounds was a much greater concentration in the lung with 3b than with 3a or 3c. gamma-Ray scintigraphs of 3a-c in rats and of 3b in a dog indicate an uptake by the brain similar to that of the bromine analogue of 3b (DOB) in humans. [82Br]-DOB has been suggested as a potential brain scanning agent for nuclear medicine; 3b would have the advantage over DOB of providing the superior gamma-ray imaging properties of 131I or 123I.

Animals↗

[A case of acute psychotic episode after a single dose of ecstasy].

Over the last 10 years or so in Europe, there has been a development of the "ecstasy" phenomenon, which is the symbol of "recreational" drugs in general. Users, either alone or in private parties, are on the increase. The phenomenon is most frequent in England and in the Netherlands, with an estimated incidence of 13-18% amongst the 18-25 years old, which may reach 52% in "exposed populations", such as individuals who go to "techno" night clubs. In France, the prevalence is uncertain, but estimated at least 5% of males between 18 and 23 years old. Several substance, with more or less the same effects, are grouped together by the term "ecstasy", the best-known one being 3,4-methylenedioxymethamphetamine (MDMA), but there are also an N-demethylated derivative (MDA), methylenedioxyethylamphetamine (MDEA), N-methyl-benzodioxazolylbutanamine (MBDB) and 4-bromo-2,5-dimethoxyphenylethylamine (2-CB or Nexus). The psychopathological consequences of MDMA in man are relatively poorly understood. On the basis of series of cases reported in the literature, acute psychosis, chronic psychosis similar to paranoid delusions, flash-back phenomena similar to with LSD, anxiety/panic states and depressive mood disorders may occur. The case which we report is therefore that of an acute psychotic episode, with residual symptomatology 6 months later, which occurred suddenly following absorption of toxic substances (alcohol and ecstasy), at least 12 hours after taking the ecstasy tablet without his knowing it, in an individual without any previous psychopathology, other than moderate social phobia. Twelve cases of acute psychotic episodes after ecstasy have been reported in the literature. Two of them occurred after a single dose and one after 2 doses. No author was able to examined the previous history of the individuals accurately, nor any possible psychopathological history. Our patient did not have any previous history of psychosis, using a standardized validated interview, which his peers and family confirmed. He did however fulfil the criteria of "social phobia". Retrospectively, we noted the extent of his psychomotor disinhibition with ecstasy, which seemed to be proportional to the intensity of his previous social inhibition. This point does not explain the psychotic episode. From a neurobiologic point of view, acute psychotic disorders are often related to dysfunction of the mesolimbic dopaminergic system. During the first 3 hours, the effect of absorption of MDMA is a massive release of the serotonin, dopamine and noradrenaline stocks. Later, an acute hyposerotoninergic state is present. In our observation, the psychotic disorder appeared at least 12 hours after taking ecstasy, during the reduction phase of the intoxication. Toxicological analysis of the blood was negative (this detection is only positive for 24 hours). Like other authors, our hypothesis is that serotoninergic dysregulation affects the dopaminergic system. Sudden disappearance of serotoninergic feedback on the dopaminergic pathways, may contribute to an increase in the mesolimbic hyperdopaminergic state. In animals, it has been shown that serotonin depletion induced by MDMA, unmasks the effects of a hyperdopaminergic state. In addition, although it has not been mentioned much in the literature, MDMA disturbs dopaminergic function either directly, or through the peptidergic systems (neurotensin, substance P, dynorphines). A consistent series of arguments therefore suggest that there is a sudden central hyperdopaminergic state, which may be related to the appearance, sometimes de novo, of an acute psychotic disorder. From the published cases, psychotic disorders following absorption of ecstasy, appear to become chronic. Most of the cases occurred in individuals, who either abused multiple substances or were chronic ecstasy users. In a case like the one we report, in an individual with good general health, who is not a drug user and who has an acute episode following a single dose, the prognosis should be good. Similarly, a team from Milan has described the experience of 3 friends who had a brief psychotic episode, following ingestion of substances containing ecstasy. These episodes resolved completely, after rehydration and anxiolytic treatment. However, after 6 months' follow-up, our patient still has psychotic symptoms, albeit mild, but which were not present before the intoxication. The patient and his psychiatrist do not envisage changing or stopping his antipsychotic treatment. Other authors have described a lesion in the serotoninergic neurons, by making a parallel with toxic effects described in animals, in particular in primates, with MDMA. Degradation of the serotoninergic cell bodies and nerve endings has been suggested to occur with high doses and/or repeated doses of MDMA. Other authors show the large variations in MDMA and MDA metabolism. (ABSTRACT TRUNCATED)

Adult↗

Fine structural specificity differences of trimethoprim allergenic determinants.

BACKGROUND: Adverse reactions, including immediate hypersensitivity, to the widely used antibacterial agent trimethoprim occur quite frequently. In recent years some progress has been made in developing an immunoassay to aid diagnosis of type 1 allergic reactions to trimethoprim and to define the basis of IgE antibody recognition of the drug. OBJECTIVES: The molecular basis of IgE binding to trimethoprim was examined more closely with a view to defining the fine structural recognition differences between patient's sera. Utilization of such information may lead to immunoassays that are more specific and sensitive and of greater diagnostic value. METHODS: Immunoassays for specific IgE antibodies and quantitative hapten inhibition studies with trimethoprim and selected structural analogues were employed, together with sera from eight subjects clearly defined clinically as allergic to trimethoprim. RESULTS: Three different allergenic determinant structures have been identified on the trimethoprim molecule. Identification of the 3,4-dimethoxybenzyl group as a determinant was achieved on the basis of inhibitory activities of diaveridine, 3,4-dimethoxyphenylethylamine, 3,4-dimethoxybenzoic acid and 3,4,5-trimethoxycinnamic acid. Evidence that the opposite end of the trimethoprim molecule was not being recognized was obtained from results with some pyrimidine derivatives, each of which showed no activity. Identification of the second determinant, the 2,4-diamino-5-(3',4'-dimethoxybenzyl) pyrimidine group, rested mainly on the superior inhibitory potency of diaveridine, which differs from trimethoprim by just one methoxy group. With sera from some trimethoprim-allergic subjects, only trimethoprim was active, suggesting that the entire molecule was a third IgE-binding determinant structure. CONCLUSION: As with other drug allergenic determinants defined so far, heterogeneity of trimethoprim IgE-binding determinants exists, and fine structural differences between determinants may be as small as a single methoxy group. Identification of the 2,4-diamino-5-(3',4'-dimethoxybenzyl) pyrimidine group as an allergenic determinant increases the number of known trimethoprim determinants to three, and suggests that the number and heterogeneity of determinants will be a reflection of the number of allergic subjects studied.

Adolescent↗

New designer drug 4-iodo-2,5-dimethoxy-beta-phenethylamine (2C-I): studies on its metabolism and toxicological detection in rat urine using gas chromatographic/mass spectrometric and capillary electrophoretic/mass spectrometric techniques.

Studies are described on the metabolism and the toxicological analysis of the phenethylamine-derived designer drug 4-iodo-2,5-dimethoxy-beta-phenethylamine (2C-I) in rat urine using gas chromatographic/mass spectrometric (GC/MS) techniques, and for a particular question, using capillary electrophoretic/mass spectrometric (CE/MS) techniques. The identified metabolites indicated that 2C-I was metabolized on the one hand by O-demethylation in position 2 and 5, respectively, followed either by N-acetylation or by deamination with subsequent oxidation to the corresponding acid or reduction to the corresponding alcohol, respectively. The latter metabolite was hydroxylated in beta-position and further oxidized to the corresponding oxo metabolite. On the other hand, 2C-I was metabolized by deamination with subsequent oxidation to the corresponding acid or reduction to the corresponding alcohol, respectively. 2C-I and most of its metabolites were partially excreted in conjugated form. The authors' systematic toxicological analysis (STA) procedure using full-scan GC/MS after acid hydrolysis, liquid-liquid extraction and microwave-assisted acetylation allowed the detection of an intake of a dose of 2C-I in rat urine that corresponds to a common drug users' dose. Assuming similar metabolism, the described STA procedure should be suitable for proof of an intake of 2C-I in human urine.

Animals↗

Effects of 3,4-dimethoxyphenethylamine derivatives on monoamine oxidase.

The cactus alkaloid 3,4-dimethoxyphenethylamine and its naturally occurring N-methylated homologs inhibited the deamination of tyramine and tryptamine by rat brain monoamine oxidase. In contrast, the beta-hydroxylated derivatives of this series failed to inhibit the action of monoamine oxidase on both tyramine and tryptamine.

Animals↗

Macromerine and normacromerine biosynthesis in Coryphantha macromeris var. runyonii.

The biosynthetic conversion of epinephrine to normacromerine in Coryphantha macromeris (Engelm.) Br. and R. var. runyonii (Br. and R.) L. Benson (Cactacae) has been studied. Metanephrine, which has been isolated from this cactus and is a normal metabolite of epinephrine in mammalian systems, appeared to be the likely intermediate between epinephrine and normacromerine. Normacromerine turnover studies suggested a 16-day interval between metanephrine administration and harvest of the cacti. During this incubation period, the cacti specifically converted 4.77% of the administered DL-7-3H-metanephrine to normacromerine. Based on biochemical precedents, the postulated metabolic fate of normacromerine in the cactus was an enzymatic N-methylation to give macromerine. However, radiolabeled normacromerine was a very ineffecient precursor to macromerine.

Alkaloids↗

Cactus alkaloids XLII: 3,4-dimethoxy-beta-phenethylamine and heliamine from the Mexican cereoid Backebergia militaris.

Backebergia militaris (Andot) Bravo ex Sánchez Mejorada yielded alkaloid crystals from a fractionated ethanol extract of only 20 g of plant material. The alkaloid was identified as heliamine (6,7-dimethoxy-1,2,3,4-tetrahydroisoquinoline) hydrochloride. A second alkaloid, 3,4-dimethoxy-beta-phenethylamine hydrochloride, was crystallized after preparative TLC of the mother liquors. Both compounds were isolated previously from other cactus species.

Alkaloids↗

The action of the psychoactive drug 2C-B on isolated rat thoracic aorta.

1. 2C-B [2-(4-bromo-2,5-dimethoxyphenyl)ethylamine] elicits concentration-dependent contraction of the rat thoracic aorta (apparent pD2 = 4.55). The maximal contraction (Emax) attained with 2C-B is less than that produced by either norepinephrine (NE) or serotonin (5-HT). 2. Pretreatment with either prazosin (5 x 10(-9) - 10(-8) M) or ketanserin (5 x 10(-9) - 10(-8) M) leads to decreased slopes and Emax in the 2C-B dose-response curves. 3. 2.82 x 10(-5) M 2C-B potentiates the response to low concentrations of NE; 5 x 10(-5) M 2C-B shows similar behaviour, but with reduced Emax. At 10(-6) M 2C-B acts as a competitive 5-HT antagonist; at 2.8 x 10(-5) M, however, it behaves like a non-competitive 5-HT antagonist. 4. Removal of the endothelial lining from the aortal rings only shifts the 2C-B dose-response curve to the left. 5. These results suggest that 2C-B behaves as a partial agonist toward both alpha 1-adrenergic and 5-HT2 serotonergic receptors. The endothelium only seems to act as a diffusional barrier to the drug.

Adrenergic alpha-Agonists↗

Evaluation of 13N-amines as tracers.

The organ distribution and the metabolic fate of the 13N-amines 13N-beta-phenethylamine, 13N-n-octylamine, and 13N-3,4-dimethoxyphenethylamine, were studied in detail. After administration 13N-amines were rapidly transferred to tissues and oxidized by MAO. 13N-ammonia formed thereby was converted into amino acids (mainly glutamine by glutamine synthetase) and trapped. 13N-amines were found to be potential metabolic trapping tracers for the study of disposition and metabolism of amines.

Amines↗

Metabolism of the designer drug 4-bromo-2,5-dimethoxyphenethylamine (2C-B) in mice, after acute administration.

4-Bromo-2,5-dimethoxyphenethylamine (2C-B) is a psychoactive drug of abuse often sold under the general street name "Ecstasy". Recent reports on the abuse of 2C-B and analogues denote the lack of knowledge on this drug metabolism. In the present study, we investigated the metabolic profile of 2C-B in the mouse and found unchanged 2C-B and several metabolites, which could be identified by GC/MS in the mice urine. The identification of 2C-B metabolites may give important clues for the biological and toxicological effects of this drug of abuse and provides new important data for forensic analysis on samples taken from 2C-B abusers.

Animals↗