Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0036341 (schizophrenia)
 60,220 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Plasma samples were collected from 41 patients who met DSM-III criteria for schizophrenia and from 34 healthy controls. Phenylethylamine (PE) levels were determined using a gas chromatography-mass spectrometry negative chemical ionization method. PE was significantly higher in the schizophrenic patients compared with controls. There were no differences in PE between paranoid and nonparanoid patients. Plasma PE did not appear to be influenced by the severity of schizophrenic symptoms (rated by BPRS, SANS, and SAPS) or by the amount of dietary phenylalanine ingested within 24 hr of testing. Plasma PE did not correlate with current or past exposure to neuroleptic medication. It was not possible, however, to test individual patients during two periods when they were taking and not taking medication. Thus it is possible that neuroleptic exposure may have confounded the results. This study provides further evidence that PE excess may play a role in the etiology of schizophrenia but does not support previous studies which suggest that such an abnormality is limited to the paranoid subgroup.
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PMID:Plasma phenylethylamine in schizophrenic patients. 191 6

beta Phenylethylamine (PEA) is an endogenous amine that resembles amphetamine in chemical structure and has been identified in human and other mammalian brains and in many peripheral tissues. Although PEA exists in much smaller amounts than monoamines, the mode of action of PEA as a neuromodulator is of special interest. In this paper the author reviews animal and clinical studies on PEA. The first section deals the methods for the determination of PEA in mammalian brains and human urine. PEA is reliably measured using spectrofluorometric, gas chromatographic-mass spectrometric methods. The second chapter reviews the changes in animal behavior elicited by PEA. The administration of PEA induces stereotypy and increased motor activity in animals. The third part reviews the effect of PEA on dopamine, noradrenaline, serotonin and tyramine metabolism in mammalian brains. The fourth chapter examines recent clinical evidence suggesting a role for PEA in schizophrenia and affective disorders.
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PMID:[beta Phenylethylamine: psychopharmacological and clinical aspects]. 310 12

A highly purified individual form of monoamine oxidase (MAO-11b) has been isolated by means of affinity chromatography on AH-Sepharose 4B after solubilization of biomembranes from schizophrenic or normal brain tissues. The enzyme preparations obtained catalyzed deamination (both in schizophrenia and normal state) not only of serotonin and 2-phenylethylamine but also of histamine and contained about 2 SH-groups per 10(5) dalton of protein which is characteristic for "transformed" MAO with partially oxidized SH-groups. Preincubation of MAO-11b from normal brain with 10 mM dithiothreitol caused "re-transformation" of MAO: there was a marked decrease in histamine deaminating activity with simultaneous increase in the MAO activity and in content of SH-groups. In schizophrenia the re-transformation of MAO was impaired: preincubation of MAO-11b under the same conditions led to an increase in content of SH-groups and in MAO activity but the preincubation with a reducing agent did not decrease (causing, to the contrary, a marked increase) the deamination of histamine.
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PMID:[Defect in the properties of brain mitochondrial monoamine oxidase in schizophrenia]. 395 20

Phenylethylamine (PEA) is an endogenous substance with amphetamine-like stimulant properties. On the basis of this ability an abnormal brain PEA metabolism has been proposed as an etiological factor in some forms of schizophrenia. In the present study 28 schizophrenic patients and 15 healthy controls were investigated. No significant difference from control values was found in PEA concentration in cerebrospinal fluid (CSF) of either untreated of neuroleptic-treated schizophrenics. However, 2 schizophrenics with highest BPRS scores had extremely high PES concentrations. Free phenylacetic acid (PAA), the major metabolite of PEA, was significantly decreased in ummedicated but not in drug-treated schizophrenics. Because of the assumed neuromodulatory properties of PEA, it is suggested that lowered PAA concentrations and the tendency for PEA to be elevated may imply that altered central neurotransmission occurs in certain forms of schizophrenia.
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PMID:Phenylethylamine and phenylacetic acid in CSF of schizophrenics and healthy controls. 613 17

1. Some recent research on the behavioural effects of phenylethylamine and some recent data implicating the trace amines in schizophrenia, agoraphobia and aggression are briefly outlined. 2. Phenylethylamine produces in mice a distinctive hyperactivity syndrome consisting of two phases; it appears to act via dopamine and 5-hydroxytryptamine on different components of these stereotypies. 3. Urinary unconjugated tryptamine, and meta- and para-tyramine appear to be excreted in reduced amounts in schizophrenia and bipolar depression. 4. The blood levels of the trace acids phenylacetic and meta- and para-hydroxyphenylacetic are reduced in schizophrenia. 5. Blood levels of conjugated phenylacetic and unconjugated para-hydroxyphenylacetic acid are reduced in violent as opposed to non-violent offenders. 6. The neuromodulatory role of the trace amines and their possible involvement in components of behaviour and certain mental disorders are discussed.
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PMID:Some aspects of basic psychopharmacology: the trace amines. 629 92

Urinary phenylacetic acid (PAA) excretion was found to be decreased in a group of chronic schizophrenic patients, particularly in a nonparanoid subtype. No significant change in PAA excretion was observed in a group of 21 unipolar depressed patients. Urinary PAA was studied following the administration of phenylethylamine, monoamine oxidase inhibitors, a dopa decarboxylase inhibitor, a low phenylalanine diet, and phenylalanine loads in several groups of psychiatric patients and normal volunteers. While Phenylethylamine ingestion increased urine PAA, inhibition of both phenylethylamine metabolism and synthesis failed to alter urine PAA. These studies suggest that urine PAA is primarily derived from phenylalanine transamination or pathways not involving monoamine oxidase or both. The observed decrease in PAA excretion in some schizophrenic patients may reflect an alteration in this pathway. The high phenylethylamine excretion previously reported in some chronic schizophrenic patients is not directly related to the observed low PAA excretion. Therefore measurement of urine PAA is not expected to be useful in assessing any phenylethylamine abnormalities in psychiatric disorders. The possible contribution of reduced phenylalanine transamination and its subsequent increased availability for the possible synthesis of phenylethylamine in schizophrenia is discussed.
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PMID:Phenylacetic acid excretion in schizophrenia and depression: the origins of PAA in man. 671 36

This study reports the application of Nile blue (NB), a farred oxazine label, as a precolumn derivatization reagent for the measurement of free levels of phenylacetic acid (PAA) in plasma. The measurement of PAA in psychiatric populations is important because it provides a marker for 2-phenylethylamine (PEA), which has been implicated in the pathogenesis of schizophrenia and major depression. PAA was derivatized with NB through an amide linkage in the presence of 2-chloro-1-methylpyridinium iodide (carboxylic acid activator, CMP) and triethylamine (base catalyst, TEA), respectively. The formation of the NB-PAA derivative was confirmed using normal phase and reversed phase thin-layer chromatography, reversed phase liquid chromatography, and electrospray mass spectrometry. The formation of the NB-PAA derivative was optimized using a sequential single factor approach. The optimal conditions for the formation and chromatographic separation of the derivative were determined to be 8.0 nmol/mL NB, 390 nmol/mL CMP, 2 mumol/mL TEA, a reaction time of 45 min, and a reaction temperature of 25 degrees C. This derivatization scheme was performed in a phase transfer catalysis mode that enabled the simultaneous extraction, preconcentration, and derivatization of the analyte in a single step. The limit of derivatization of PAA was determined to be 1.0 x 10(-9) M in phosphate-buffered saline, a PAA-free matrix. This derivatization was limited not by the kinetics of the reaction but by the chromatographic separation of the derivative from a side reaction product. The method was used to estimate endogenous free levels of PAA in human plasma samples. The levels of PAA in four sources of plasma were determined to be within 30-70 ng/mL using the method of standard addition and reflected levels that have been reported in the literature. The limit of detection of the derivative was determined to be 7.33 x 10(-11) M using a laboratory-constructed HPLC-VDLIF detector.
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PMID:Visible diode laser-induced fluorescence detection of phenylacetic acid in plasma derivatized with Nile blue and using precolumn phase transfer catalysis. 925 52

Aromatic L-amino acid decarboxylase (AADC) is rate limiting in the production of 2-phenylethylamine (2PE). AADC activity and 2PE serum concentrations have been found to be increased in schizophrenic patients. Both antipsychotic and psychotogenic drugs, including amphetamine, affect the activity and encoding mRNA levels of AADC. Amphetamine is an analogue of 2PE and has a similar physiological effect. We have looked at the effects of chronic (32 day) treatment of rats with LSD (0.12 microg/kg/day) and phencyclidine (PCP; 10 mg/kg/day) on AADC mRNA levels. Both drugs up-regulated AADC mRNA levels in striatum, nucleus accumbens, hippocampus and cerebellum by between 50% and 150%. A splicing variant of AADC, present in human brain, which lacks the 3rd exon does not appear to be present in rat brain. These results are consistent with the hypothesis that over activity of AADC leading to increased production of 2PE is involved in endogenous psychosis such as schizophrenia.
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PMID:Does phenylethylamine have a role in schizophrenia?: LSD and PCP up-regulate aromatic L-amino acid decarboxylase mRNA levels. 938 86

Aromatic L-amino acid decarboxylase (AADC) is a relatively non specific enzyme involved in the biosynthesis of several classical neurotransmitters including dopamine and 5-hydroxytryptamine (5HT; serotonin). AADC does not catalyse the rate limiting step in either pathway, but is rate limiting in the synthesis of 2-phenylethylamine (2PE) which is a positive modulator of dopaminergic transmission and a candidate natural psychotogenic compound.1 We and others have proposed that polymorphism in AADC resulting in altered 2PE activity might contribute to the pathogenesis of psychosis. In order to test this hypothesis, we have used denaturing high performance liquid chromatography (DHPLC)3 to screen 3943 bases of the AADC gene and its promoter regions for variants that might affect protein structure or expression in 15 unrelated people with schizophrenia, and 15 unrelated people with bipolar disorder. Three polymorphisms were identified by DHPLC: a insertion/deletion polymorphism in the 5' UTR of the neuronal specific mRNA (g.-33-30delAGAG, bases 586-589 of GenBank M77828), a T>A variant in the non-neuronal exon 1 (g. -67T>A, GenBank M88070), and a G>A polymorphism within intron 8 (g. IVS8 +75G>A, GenBank M84598). Case-control analysis did not suggest that genetic polymorphism in the AADC gene is associated with liability for developing schizophrenia or bipolar disorder.
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PMID:Comparative sequencing and association studies of aromatic L-amino acid decarboxylase in schizophrenia and bipolar disorder. 1088 38

Phenyl acetic acid, a metabolite of 2-phenyl ethylamine, acts as a neuromodulator in the nigrostriatal dopaminergic pathway stimulating the release of dopamine. The evaluation of phenyl acetic acid concentration in the biological fluid reflects phenyl ethylamine levels thus allowing the assessment of the modulatory role of this endogenous substance. Changes in biological fluids levels of 2-phenylethylamine and/or in its metabolite have been reported in affective disorders, such as depression and schizophrenia. Recently, the occurrence of the "attention deficit hyperactivity syndrome" has been frequently reported in childhood population and involvement of dopaminergic dysfunction in this disease has been suspected. A fast, reliable and reproducible method for the determination of phenyl acetic acid in human blood, is therefore needed in order to have a screening tool for monitoring both healthy childhood population and suspected "attention deficit hyperactivity syndrome" patients. The gas chromatographic-mass spectrometric method here described makes use of a deuterated internal standard in order to overcome problems related to the lack of reproducibility often encountered when a derivatization step is performed.
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PMID:Gas chromatographic--mass spectrometric determination of phenylacetic acid in human blood. 1550 22


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