Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.4.16.2 (PCP)
 3,761 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The release of free [3H]arachidonic acid and its metabolites (AAM) from mouse embryo cortical neurones cultured in serum-free medium stimulated by beta-endorphin C-terminal dipeptide (glycl-L-glutamine, Gly-Gln) was investigated. Gly-Gln but not the related dipeptide, glycyl-glutamic acid, caused a 2-fold elevation of AAM release which was blocked in the absence of extracellular calcium, in the presence of 5 mM magnesium and by the phospholipase A2 (PLA2) inhibitor, mepacrine. Other proopiomelanocortin (POMC) peptides did not elicit AAM release. The response to Gly-Gln was unaffected by D-amino-2-phospho-5-valeric acid (AP5) and 7-chlorokynurenic acid (7-ClKY), antagonists respectively at the ligand and allosteric glycine binding sites of the NMDA glutamate receptor subtype. However, it was inhibited in a dose-dependent manner by antagonists at the phencyclidine (PCP) and sigma sites. The results suggest that Gly-Gln causes AAM release by activating PLA2 through the mediation of a PCP/sigma-like receptor.
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PMID:Beta-endorphin C-terminal peptide evokes arachidonic acid release from cortical neurones. 190 34

Some unnatural opiates, which do not interact with classical opiate receptors, interact with phencyclidine (PCP) receptors. Among their many pharmacological actions, drugs which bind to the PCP receptor antagonize the actions of glutamic acid mediated via the NMDA excitatory amino acid receptor, leading to their potential use as anti-ischemic and anticonvulsant agents. Despite an enormous effort, identification of a PCP receptor antagonist, which would be useful for research and therapeutics, has not yet been reported. Chemical modification of unnatural opiates as a means to produce a PCP antagonist, or PCP agonists with properties different than PCP, has not been fully explored. Towards this end, we determined the equilibrium dissociation constants of eight enantiomeric pairs of opiates for the rat brain PCP receptor.
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PMID:Interaction of enantiomeric pairs of opiates with phencyclidine binding sites in rat brain: identification of (+) pentazocine as a ligand potentially suitable for imaging sigma binding sites using positron emission tomography. 284 88

The enthalpy changes that occur in the self-assembly of tubulin into microtubules were examined by adiabatic differential heat capacity microcalorimetry and by isothermal batch microcalorimetry. Tubulin solutions at concentrations between 7 and 17 mg/mL were heated from 0 to 40 degrees C at heating rates of 1 or 2 deg/min in pH 6.8 or 7.0 assembly buffers containing 20 mM MES, 100 mM glutamic acid, 5 mM MgCl2, 3.4 M glycerol, and either 0.5 mM GMP-PCP or 1 mM GTP. The assembly reaction in the presence of GTP was characterized by a complex heat-uptake pattern consisting of a broad endotherm with a sharper exotherm superimposed on it, similar to assembly in a GTP phosphate buffer [Hinz, H.-J., Gorbunoff, M.J., Price, B., & Timasheff, S.N. (1979) Biochemistry 18,3084]. Replacement of GTP by the nonhydrolyzable analogue resulted in a pattern typical for an endothermic reaction only. These results have permitted the assignment of the endothermic process to microtubule assembly and of the exothermic process to the resultant GTP hydrolysis. In these studies equilibration was found to be slow, several hours of cooling being required for the system to return to its original state. Turbidity scans also revealed hysteresis between consecutive scans and a displacement of the depolymerization transition midpoint to a lower temperature than that of assembly. The disassembly of microtubules was examined in batch calorimetry experiments in pH 7.0 phosphate, 1 mM GTP, 16 mM MgCl2, and 3.4 M glycerol, in which tubulin assembled into microtubules was diluted to below the critical concentration.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Enthalpy changes in microtubule assembly from pure tubulin. 381 84

Ion entry into neurons occurs either through receptor-operated channels (ROC) or voltage-operated channels (VOC). The function of ROC depends crucially on the action of agonists, antagonists or compounds modulating particular types of receptors (GABA A, NMDA, Ach N receptors). The function of VOC is closely connected with the activity of protein kinases and the processes of phosphorylation of membrane proteins (K+, Na+, Ca2+ channels). Gamma aminobutyric acid (GABA) is the main inhibitory neurotransmitter in the vertebrate brain. The GABA A receptor is a oligomeric complex of multiple binding sites and chloride channel. This complex contains recognition sites for GABA, anxiolytics such as benzodiazepine, anxiogenic--beta-carboline, and convulsant such as picrotoxin. Chloride ion channel plays a crucial role in anxiogenic, anxiolytic and convulsant activities. Glutamic acid is the main endogenous neurotransmitter for N-methyl-D-aspartate (NMDA)-type excitatory amino acid receptor. NMDA receptors connected with Ca2+ channel, have multiple modulatory sites which are affected by a wide range of compounds. There are NMDA and competitive NMDA antagonists site, the glycine site, the phencyclidine (PCP) site and the binding site of Mg2+ ions in this receptor complex. Calcium entry through NMDA receptors may be important in the etiology of many psychiatric disorders. VOC mediate rapid, voltage-gated changes in ion permeability during action potentials in neurons. Electrophysiological studies indicate the existence of three types of VOC (K+, Na+, Ca2+ channels). In number of neurons various subtypes of Ca2+ channels (P, T, N and L-type) occur together. Among them, the L-type calcium channel has been first described and most thoroughly studied. The L-type calcium channel is localized on nerve terminals in the pre and postsynaptic parts, as well as on cell bodies and may be involved in the mechanism of action of psychotropic drugs. Chronic treatment with various psychotropic drugs changes the density of voltage-dependent Ca2+ channels in the central nervous system. Thus calcium entry through both VOC and ROC may be important in the etiology of many psychiatric disorders.
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PMID:Receptor and voltage-operated ion channels in the central nervous system. 871 58

The acidic lipopeptides, including the calcium-dependent antibiotics (CDA), daptomycin, and A54145, are important macrocyclic peptide natural products produced by Streptomyces species. All three compounds contain a 3-methyl glutamate (3-MeGlu) as the penultimate C-terminal residue, which is important for bioactivity. Here, biochemical in vitro reconstitution of the 3-MeGlu biosynthetic pathway is presented, using exclusively enzymes from the CDA producer Streptomyces coelicolor. It is shown that the predicted 3-MeGlu methyltransferase GlmT and its homologues DptI from the daptomycin producer Streptomyces roseosporus and LptI from the A54145 producer Streptomyces fradiae do not methylate free glutamic acid, PCP-bound glutamate, or Glu-containing CDA in vitro. Instead, GlmT, DptI, and LptI are S-adenosyl methionine (SAM)-dependent alpha-ketoglutarate methyltransferases that catalyze the stereospecific methylation of alpha-ketoglutarate (alphaKG) leading to (3R)-3-methyl-2-oxoglutarate. Subsequent enzyme screening identified the branched chain amino acid transaminase IlvE (SCO5523) as an efficient catalyst for the transformation of (3R)-3-methyl-2-oxoglutarate into (2S,3R)-3-MeGlu. Comparison of reversed-phase HPLC retention time of dabsylated 3-MeGlu generated by the coupled enzymatic reaction with dabsylated synthetic standards confirmed complete stereocontrol during enzymatic catalysis. This stereospecific two-step conversion of alphaKG to (2S,3R)-3-MeGlu completes our understanding of the biosynthesis and incorporation of beta-methylated amino acids into the nonribosomal lipopeptides. Finally, understanding this pathway may provide new possibilities for the production of modified peptides in engineered microbes.
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PMID:Stereospecific enzymatic transformation of alpha-ketoglutarate to (2S,3R)-3-methyl glutamate during acidic lipopeptide biosynthesis. 1778 61

We investigated the involvement of glutamic acid in neural development by injecting phencyclidine (PCP) into neonatal ICR mice. Neonatal mice were injected with PCP at 10 mg/kg or saline on postnatal days 7, 9 and 11, and their behavioral, anatomical and neurochemical changes were analyzed in adulthood. PCP-treated mice exhibited an increase in PCP-induced hyperactivity and impairments of spatial working memory and social interaction behavior. The impairment of social interaction behavior was significantly reversed by administration of clozapine, D-cycloserine, flumazenil, or SHC50911, a gamma-aminobutyrate B (GABA(B)) receptor antagonist. A decrease in the number of parvalbumin-positive cells and spine density in the frontal cortex, nucleus accumbens and hippocampus were evident in the brains of PCP-treated mice. Measurement of brain monoamine and their metabolite contents in adulthood indicated brain area-dependent and neurotransmitter-specific changes in monoamine metabolism. These findings suggest that neonatal treatment with PCP in mice leads to enhanced sensitivity to PCP and impairment of spatial working memory and social interaction behaviors in adulthood, which may be associated with reduced spine density and GABAergic interneurons and changes in monoamine metabolism. Furthermore, pharmacologic experiments suggest the potential applicability of neonatally PCP-treated mice as a useful animal model for new antipsychotic drug screening.
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PMID:Neonatal phencyclidine treatment in mice induces behavioral, histological and neurochemical abnormalities in adulthood. 1972 Dec 35

The effects of glutamate receptor agonists and antagonists on l-[(3)H]noradrenaline (NA) release were examined in cerebral cortical and hippocampal slices of mice by superfusion methods. N- Methyl- d -aspartate (NMDA) at 100 ?M significantly stimulated l-[(3)H]NA release. The NMDA-induced l-[(3)H]NA release was inhibited by Mg(2+) in a concentration-dependent manner. APV (100 ?M), phencyclidine (PCP, 10 ?M) and MK-801 (10 ?M) caused a significant inhibition in the NMDA (100 ?M)-induced l-[(3)H]NA release, but (+)3-PPP did not. Enhancement by NMDA of a high K(+)-evoked l-[(3)H]NA release was suppressed by APV (200 ?M), PCP (1 ?M) and MK-801 (1 ?M). In contrast, quisqualate (QA, 10 and 100 ?M) and kainate (KA, 10 and 100 ?M) stimulated the release in the presence of Mg(2+). QA-induced release was inhibited by the toxin of Nephila maculata (1 ?M), a Papua New Guinean spider (NSTX), and l-glutamic acid diethyl ester (100 and 500 ?M). NMDA, QA and KA did not affect the l-[(3)H]NA uptake into brain slices, but (+)3-PPP, PCP and MK-801 inhibited the uptake with the order of inhibitory potency of PCP > (+)3-PPP ? MK-801. It is suggested that the NMDA receptor channel complex evokes NA release and enhances a depolarization-induced NA release without the regulation of the uptake. Opiate sigma (?)-receptors, however, may be involved in the uptake of NA.
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PMID:Involvement of glutamate receptor subtypes in l-[(3)H]noradrenaline release from cerebral cortical and hippocampal slices of mice. 2050 35

This study aimed to assess the molecular mechanism of the histone deacetylase inhibitor (HDACI) valproate acid (VPA) alone or in combination with the antipsychotic drug chlorpromazine in the epigenetic regulation of schizophrenia. A total of 60 perinatal CD-SD rats were divided in a control group (16 animals) and a schizophrenia model group (44 animals). For the schizophrenia model group the rats received phencyclidine (PCP) 10 mg/kg/day by intradermal injection on days 7, 9, and 11 after birth. The model was confirmed by the Morris water test in 40 rats. The control and model rats were divided into 7 groups. The Real Time PCR assay was used to detect the mRNA expression changes of GABA system gene [GABBR1 (GABA B receptor 1)], GAD1 (glutamic acid decarboxylase1), GAD2 (glutamic acid decarboxylase2), Lipase metabolic key enzyme LPL (lipoprotein lipase) gene, glutamate neurotransmitter gene GRIA2 (AMPA subtype glutamate receptors 2), inward rectifier potassium channel members KCNJ4 (potassium voltage-gated channel subfamily J member 4) and neuropeptide signal gene TAC1 (tachykinin precursor 1,TAC1) in four brain regions: the prefrontal cortex (PC), the amygdala (AM), the caudate-putamen (CPU) and the hippocampus (HIP). The platform arrival time of PMV and PMVC groups was significantly reduced compared to the PM group, the reduction being more significant in the PMV group. In the four brain regions of the epigenetic animal model of schizophrenia, the expression of GABBR1, GAD1, and GAD2 genes increased significantly. Following administration of HDACI VPA, the mRNA expression of this gene in the four brain regions decreased or approached normal levels. GABBR1 GAD1 and GAD2 are likely to be the target genes affected by the HDACI VPA.
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PMID:Molecular mechanism of action of valproate acid alone or in combination with chlorpromazine in the epigenetic regulation of schizophrenia. 3057 48