Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.4.16.2 (PCP)
3,761 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Recent evidence suggest that the N-methyl-D-aspartate (N-Me-D-Asp) channel is functionally and structurally associated with the phencyclidine (PCP) receptor, which mediates the psychotomimetic effects of PCP, sigma opioids, and dioxalanes. To investigate the relationship between N-Me-D-Asp and PCP receptors on a molecular level, we injected mRNA isolated from adult rat brain into Xenopus oocytes. In injected oocytes N-Me-D-Asp application (with glycine) evoked a partially desentizing inward current that was potentiated by glycine and blocked by D-(-)-amino-5-phosphonovaleric acid (D-APV), by Zn2+ and, in a voltage-dependent manner, by Mg2+. These results show that the distinguishing features of rat brain N-Me-D-Asp channels are reproduced in this translation system. In addition, kainic acid elicited a nondesensitizing inward current at short latency, and quisqualate elicited a delayed oscillatory inward current, presumably mediated by a second-messenger system. Responses to glutamate had both short-latency and delayed components. The PCP derivative N-[1-(2-thienyl)cyclohexyl]piperidine (TCP) blocked the N-Me-D-Asp-evoked current, and its potency was comparable to its binding affinity in rat brain membranes. Onset of block required the presence of antagonist. Antagonism was stereoselective in that the active ligand dexoxadrol was a more effective blocker than its relatively inactive stereoisomer levoxadrol. adrol. Other PCP receptor ligands, (+)SKF-10,047 and MK-801, also blocked. Potencies of compounds active at N-Me-D-Asp and PCP receptors in oocytes were comparable to those obtained previously in electrophysiological and binding assays on neural tissues. These results indicate the coexpression of neuronal PCP and N-Me-D-Asp receptors in Xenopus oocytes.
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PMID:Coexpression of N-methyl-D-aspartate and phencyclidine receptors in Xenopus oocytes injected with rat brain mRNA. 283 39

The nature of the interactions between the N-methyl-D-aspartate (NMDA) and the phencyclidine (PCP) receptors was studied in membranes obtained from rat cerebral cortex and washed repeatedly to remove endogenous excitatory amino acids. Binding of [3H]-N-[1-(2-thienyl)cyclohexyl]piperidine ([3H]TCP) to its receptor sites in these membranes proceeded slowly and did not reach equilibrium even after incubation for 4 h at 25 degrees C. The dissociation rate of [3H]TCP-receptor complexes was also slow (t1/2 = 128-165 min). Both association and dissociation followed first-order reaction kinetics, with similar time constants (0.0054 min-1). Addition of glutamate and glycine to the washed membranes was immediately followed by a marked increase in the rates of both association of [3H]TCP with the receptors and its dissociation from them (t1/2 = 8 min). Association now followed second-order reaction kinetics. Accelerated association of [3H]TCP with its binding sites could also be induced by NMDA or by glutamate alone, and glycine enhanced the effect. All effects of glutamate and glycine on [3H]TCP binding kinetics were blocked by the competitive NMDA receptor antagonist AP-5 [D-(-)-2-amino-5-phosphovaleric acid]. [3H]TCP-receptor interactions at equilibrium were not altered by AP-5 or by glutamate and glycine. The binding data were fitted to a model in which interactions of [3H]TCP with the receptor involve a two-step process: the outside ligand must cross a barrier (presumably a closed NMDA receptor channel in the absence of agonists). Once agonists are added, this limitation is removed (presumably because the channel is open).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Kinetic characterization of the phencyclidine-N-methyl-D-aspartate receptor interaction: evidence for a steric blockade of the channel. 283 78

The effect of tetrahydro-9-aminoacridine (THA) and related compounds on ligand binding to the dissociative anesthetic (phencyclidine, PCP) receptor site was assessed using a rat brain homogenate assay. THA displaced the dissociative anesthetic ligand [3H]N-(1-[2-thienyl]cyclohexyl)3-4-piperidine [( 3H]TCP) binding with an IC50 of 26 microM. Other acridine derivatives displayed similar potency as displacers of [3H]TCP. Cholinesterase inhibitors and aminopyridines had IC50s equal to or greater than 100 microM. Saturation studies of [3H]TCP in the presence and absence of 30 microM THA revealed competitive inhibition with a K1 of 15 microM. The clinical pharmacology of THA suggests that it antagonizes the effects of dissociative anesthetics whereas in vitro, it behaves as a weak PCP agonist. THA may exert some of its clinical effects through interaction with the PCP receptor, and may have mixed agonist-antagonist properties.
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PMID:Tetrahydro-9-aminoacridine (THA) interacts with the phencyclidine (PCP) receptor site. 283 71

Opioid, sigma, and phencyclidine (PCP) receptors were characterized in the mouse neuroblastoma--Chinese hamster brain hybrid cell line NCB-20. Quantitative receptor assays under equilibrium binding conditions with highly specific radioligands demonstrated the presence of delta, but not mu or kappa, opioid receptors on NCB-20 cell membranes. NCB-20 cells were shown to possess two distinct sites specific for sigma opioids and PCP derivatives. One site was labeled by (+)-[3H]N-allylnormetazocine [(+)-[3H]SKF-10,047] (Kd = 69 nM; Bmax = 4100 fmol/mg of protein). The rank order of potency of drugs at this site was (+)-3-(3-hydroxy-phenyl)-N-(1-propyl)piperidine [(+)-3-PPP] greater than haloperidol greater than (+)-SKF-10,047 greater than (+/-)-ethylketocyclazocine greater than (+/-)-bremazocine greater than N-[1-(2-thienyl) cyclohexyl]piperidine (TCP) greater than dexoxadrol. This site is similar in its ligand selectivity to the haloperidol-sensitive sigma receptor of rat brain. The other site was labeled by the potent phencyclidine derivative [3H]TCP (Kd = 335 nM; Bmax = 9300 fmol/mg of protein). This density is equivalent to approximately 60,000 sites/cell. The rank order of potency of drugs at this site was TCP greater than (+)-3-PPP greater than PCP greater than dexoxadrol greater than haloperidol greater than cyclazocine greater than levoxadrol greater than (+)-SKF-10,047; mu and delta ligands were inactive. This site is similar to the rat brain PCP receptor. The NCB-20 cell line is the only cultured cell line that has been demonstrated to have PCP receptors.
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PMID:Characterization of opioid, sigma, and phencyclidine receptors in the neuroblastoma-brain hybrid cell line NCB-20. 284 88

Phencyclidine (PCP) has been reported to suppress a variety of immune functions in vitro. Because PCP binds with high affinity to both PCP and sigma receptors, the identity of the receptor(s) mediating the immunological effects of PCP is unknown. The aim of the present study was to identify and characterize the sites of PCP action (sigma and/or PCP receptors) in human peripheral blood leukocytes (PBL) using [3H]haloperidol or 1,3 di(2-([5-3H]tolyl)guanidine ([3H]DTG) to specifically label sigma receptors and 3,4-[3H]-(N)-[1-(2-thienyl)-cyclohexyl]-piperidine ([3H]TCP) to specifically label PCP receptors. [3H]Haloperidol binding was saturable and of high affinity with comparable KD values in human PBL (0.44 +/- 0.10 nM) and rat cerebellum (0.51 +/- 0.09 nM). Similarly, [3H]DTG binding was saturable with comparable KD values of 29.5 +/- 3.5 and 26.4 +/- 3.6 nM in rat cerebellum and human PBL, respectively. In contrast, there was a notable absence of [3H]TCP-labeled PCP receptors in human PBL and rat cerebellum. In competition studies, the pharmacologic profile of [3H]haloperidol-labeled sigma receptors in human PBL was virtually identical with that in rat cerebellum (slope, 0.87; correlation coefficient, 0.96); the rank order of potency of competing drugs was haloperidol greater than l-butaclamol = pentazocine greater than d-3-(hydroxyphenyl)-N-(1-propyl)-piperidine greater than DTG = d-butaclamol = d-SKF 10,047 greater than levallorphan greater than or equal to PCP greater than or equal to l-SKF 10,047 greater than TCP greater than MK-801.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Initial identification and characterization of sigma receptors on human peripheral blood leukocytes. 284 60

To compare the actions of prototypic drugs which are selective for phencyclidine and sigma receptors, the electrophysiological effects of phencyclidine (PCP),3-[3-hydroxyphenyl]-N-(1-propyl)piperidine [+)3-PPP), and 1,3-di(2-tolyl)guanidine (DTG) on CA1 hippocampal pyramidal neurons were examined. A wide range of concentrations of drug was tested to differentiate specific, receptor-mediated effects from nonselective, anesthetic-like actions. At relatively large concentrations (0.1-1 mM), each compound reversibly increased the threshold of action potentials driven by Schaffer collaterals, the duration of action potentials and membrane resistance. The low potencies and rank order of potency suggested that phencyclidine, (+)3-PPP, and DTG were not acting through either high affinity sigma or phencyclidine receptors. These compounds did have receptor-mediated effects at smaller concentrations. Since none of the compounds affected evoked excitatory or inhibitory postsynaptic potentials (EPSP or IPSP) or driven action potentials at subanesthetic concentrations (less than 100 microM), no evidence was found to support the hypothesis that the actions of phencyclidine result from enhanced release of transmitter, caused by the inhibition of a presynaptic potassium conductance. As observed in other neurons, phencyclidine blocked excitations in CA1 pyramidal cells mediated by N-methyl-D-aspartic acid (NMDA) at behaviorally relevant concentrations (1-10 microM). However, (+)3-PPP (1 microM-1 mM) enhanced the pyramidal cell response to NMDA. Alone, DTG did not effect the NMDA-induced response but did inhibit the enhancement induced by (+)3-PPP. The agonist and antagonist actions of the sigma-selective ligands, (+)3-PPP and DTG, suggests that they modify NMDA-induced responses by acting at the sigma receptor.
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PMID:Comparison of the actions of phencyclidine and sigma ligands on CA1 hippocampal pyramidal neurons in the rat. 284 30

Representatives from several chemical classes known to share behavioral properties with phencyclidine [(1-phenylcyclohexyl)piperidine] (PCP) have been shown to antagonize the excitatory effects of N-methylaspartate on spinal neurons selectively. This study compared the abilities of several of these PCP-like drugs to inhibit N-methyl-D-aspartate (NMDA)-stimulated efflux of acetylcholine in rat striatum. PCP completely inhibited this parameter with an IC50 value of 68 nM. The IC50 values (nanomolar) found for the other drugs tested were as follows: etoxadrol (98), (-)-cyclazocine (120), N-allylnormetazocine (or SKF 10047) (940), ketamine (1600) and ethylketocyclazocine (8300). Morphine had no effect at concentrations as high as 30,000 nM. In addition, 100 nM dexoxadrol, 1-[1-(napthyl)cyclohexyl]piperidine HCl (m-amino PCP) and (-)-cyclazocine inhibited NMDA-induced acetylcholine release by about 50%, whereas the same concentration of their enantiomers (or a structural analog in the case of m-amino-PCP) produced no significant effect. It was also found that 10 mg/kg of dexoxadrol, m-amino-PCP and (-)-cyclazocine induced significant ipsilateral turning in rats with unilateral destruction of the substantia nigra, whereas 10 mg/kg of levoxadrol, 1-[1-(m-nitrophenyl)cyclohexyl]piperidine HCL (m-nitro-PCP) and (+)-cyclazocine produced no such similar effect. In spite of the ability of several dopaminergic antagonists to block turning produced by (+/-)-cyclazocine, we concluded, based on our previously reported studies of the dopaminergic properties of these drugs, that turning is the result of nondopaminergic properties of the PCP-like drugs.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Antagonism of N-methyl-D-aspartate-induced transmitter release in the rat striatum by phencyclidine-like drugs and its relationship to turning behavior. 286 36

The present study provides evidence for the presence of an endogenous ligand for the phencyclidine (PCP) receptor of mammalian brain. Partially purified bovine hippocampal extracts potently and dose dependently inhibit binding to PCP receptors of [3H]N-(1-[2-thienyl]-cyclohexyl)piperidine (TCP), a highly potent and specific ligand of PCP receptors. In addition to demonstrating PCP-like binding properties, the partially purified extract mimics biological actions of PCP upon neurotransmitter release. HPLC fractions active in the [3]TCP binding assay, by contrast to fractions inactive in the binding assay, potently elicited stimulation of spontaneous acetylcholine and dopamine efflux and inhibited NMDA-stimulated release of acetylcholine and dopamine. The transmitter release assay provides validation of a PCP-like physiological activity exerted by bovine hippocampal extracts partially purified by HPLC.
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PMID:An endogenous ligand of the brain sigma/PCP receptor antagonizes NMDA-induced neurotransmitter release. 288 50

Phencyclidine (PCP) receptors were successfully solubilized from rat forebrain membranes with 1% sodium cholate. Approximately 58% of the initial protein and 20-30% of the high-affinity PCP binding sites were solubilized. The high affinity toward PCP-like drugs, the stereo-selectivity of the sites, and the sensitivity to N-methyl-D-aspartate (NMDA) receptor ligands were preserved. Binding of the potent PCP receptor ligand N-[3H][1-(2-thienyl)cyclohexyl] piperidine ([3H]TCP) to the soluble receptors was saturable (KD = 35 nM), and PCP-like drugs inhibited [3H]TCP binding in a rank order of potency close to that observed for the membrane-bound receptors; the most potent inhibitors were TCP (Ki = 31 nM) and the anticonvulsant MK-801 (Ki = 50 nM). The NMDA receptor antagonist 2-amino-5-phosphonovaleric acid inhibited binding of [3H]TCP to the soluble receptors; glutamate or NMDA diminished this inhibition in a dose-dependent manner. Taken together, the results indicate that the soluble PCP receptor preparation contains the glutamate recognition sites and may represent a single receptor complex for PCP and NMDA, as suggested by electrophysiological data. The successful solubilization of the PCP receptors in an active binding form should now facilitate their purification.
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PMID:Solubilization of rat brain phencyclidine receptors in an active binding form that is sensitive to N-methyl-D-aspartate receptor ligands. 289 2

Etoxadrol-meta-isothiocyanate (2S,4S,6S-2-ethyl-2-(3-isothiocyanatophenyl)-2-piperidyl)1,3-dioxolane, 4a) has been synthesized and characterized as an irreversible ligand for the phencyclidine (PCP)-binding site. It is the first chiral electrophilic affinity ligand for this site to have been described. This affinity ligand is based upon etoxadrol, a 1,3-dioxolane known to have PCP-like effects in vivo and in vitro. Etoxadrol-meta-isothiocyanate was found to be four-five times more potent in vitro than metaphit (1-[1-(3- isothiocyanatophenyl)cyclohexyl]piperidine), the only previously known electrophilic affinity ligand for the PCP-binding site. The binding was shown to be highly enantioselective for etoxadrol-meta-isothiocyanate (4a). The 2R,4R,6R-enantiomer of 4a was essentially inactive. The ability of the 2S,4S,6S-enantiomer (4a) to interact with the benzodiazepine, muscarinic, and mu opioid receptor systems was also examined, and it was found not to interact with these receptor systems. It seems likely that 4a will prove to be a valuable tool in the study of structure and function of the PCP-binding site.
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PMID:Etoxadrol-meta-isothiocyanate: a potent, enantioselective, electrophilic affinity ligand for the phencyclidine-binding site. 290 91


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