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 synthesis and in vitro sigma receptor activity of the two diastereomers of U50,488 [(+/-)-2], namely, (1R,2S)-(+)- cis-3,4-dichloro-N-methyl-N-[2-(1-pyrrolidinyl)cyclohexyl]benzeneacet ami de [(+)-1] and (1S,2R)-(-)-cis-3,4-dichloro- N-methyl-N-[2-(1-pyrrolidinyl)cyclohexyl]benzeneacetamide [(-)-1], are described. (+)-1 and (-)-1 were synthesized from (+/-)-trans-N-methyl-2-aminocyclohexanol [(+/-)-3]. Pyridinium chlorochromate (PCC) oxidation of the N-t-Boc-protected derivative of (+/-)-3 afforded (+/-)-2-[N- [(tert-butyloxy)carbonyl]-N-methylamino]cyclohexanone [(+/-)-5]. The sequence of enamine formation with pyrrolidine, catalytic reduction, N-deprotection, and optical resolution afforded (1R,2S)-(-)-cis-2-pyrrolidinyl-N-methylcyclohexylamine [(-)-10] and (1S,2R)-(+)-cis-2-pyrrolidinyl-N-methylcyclohexylamine [(+)-10]. The optical purity (greater than 99.5%) of (-)-10 and (+)-10 was determined by HPLC analysis of the diastereomeric ureas formed by reaction with optically pure (R)-alpha-methylbenzyl isocyanate. The absolute configuration of (-)-10 and (+)-10 was determined by single-crystal X-ray diffractometry of the bis-(R)-mandelate salt. Condensation of optically pure (-)-10 and (+)-10 with 3,4-dichlorophenylacetic acid furnished (+)-1 and (-)-1, respectively. Compounds (+)-1, (-)-1, (-)-2, and (+)-2 were compared for their binding affinities at kappa opioid, sigma, D2-dopamine, and phencyclidine (PCP) receptors in competitive binding assays using [3H]bremazocine ([3H]BREM) or [3H]U69,593, [3H]-(+)-3-(3-hydroxyphenyl)-N-(1-propyl)piperidine [[3H]-(+)-3-PPP], or [3H]-1,3-di(o-tolyl)guanidine ([3H]DTG), [3H]-(-)-sulpiride [[3H]-(-)SULP], and [3H]-1- [1-(2-thienyl)cyclohexyl]piperidine ([3H]TCP), respectively. In the systems examined, (-)-2 exhibited the highest affinity for kappa receptors, with a Ki of 44 +/- 8 nM. However, (-)-2 also showed moderate affinity for sigma receptors, with a Ki of 594 +/- 3 nM [[3H]-(+)-3-PPP]. The (1R,2R)-(+)-enantiomer, (+)-2, had low affinity for both kappa and sigma receptors, exhibiting Ki values of 1298 +/- 49 nM at kappa ([3H]BREM) and 1270 +/- 168 nM at sigma [[3H]-(+)-3-PPP]. In contrast, the chiral cis compounds (+)-1 and (-)-1 showed high affinity for sigma receptors and negligible affinity for kappa opioid receptors in the [3H]BREM assay. Compound (-)-1 exhibited a Ki of 81 +/- 13 nM at sigma receptors [[3H]-(+)-3-PPP] and 250 +/- 8 nM ([3H]DTG).(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Alterations in the stereochemistry of the kappa-selective opioid agonist U50,488 result in high-affinity sigma ligands. 254 74

Receptor binding studies with [3H]-(+)SKF-10047 were carried out to characterize the putative sigma (sigma) and phencyclidine (PCP) receptors in membrane preparations of bovine adrenal medulla. Specific binding of the radiolabelled compound was observed after incubation with the membrane preparation at 37 degrees, the equilibrium being reached at 20 min and the maximal binding being observed with 0.6 mg/ml protein. Saturation binding studies were performed at equilibrium (30 min at 37 degrees with 0.5 mg/ml of membrane protein) in the presence of haloperidol (1 microM) or 1-[1-(2-thienyl) cyclohexyl] piperidine (TCP; 0.2 microM) to block sigma or PCP receptors, respectively. The binding of [3H]-(+)SKF-10047 was characterized by two distinct components. A high affinity binding site (haloperidol sensitive) had an apparent KD of 8.3 nM and a Bmax of 67 pmol/g protein. A lower affinity binding site (TCP sensitive) had an apparent KD of 32.7 nM and a Bmax of 83 pmol/g protein. The drug specificity of the high affinity binding site resembled that of the putative sigma receptor, being potently inhibited by haloperidol and pentazocine. The binding pharmacology of the low affinity site resembled that of the phencyclidine receptor, being potently displaced by TCP and PCP. The binding of [3H]-(+)SKF-10047 to both receptors showed marked stereoselectivity for the dextrorotatory (+) isomer of SKF-10047 and was insensitive to the receptor specific opioid ligands DAGO (mu), DSLET (delta) and U-69593 (kappa). These data indicate that bovine adrenal medulla contains sigma and PCP-like receptors.
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PMID:Presence of sigma and phencyclidine (PCP)-like receptors in membrane preparations of bovine adrenal medulla. 254 82

These experiments were designed to compare phencyclidine (PCP) and sigma (sigma) receptor binding sites in the rat spinal cord by using receptor binding and autoradiographic techniques. Binding sites for 3H-TCP (3H-1-[1-(2-thienyl)cyclohexy]piperidine), a PCP receptor agonist, and (+)3H-3-PPP (3H-(+)-3-(3-hydroxyphenyl)-N-(1-propyl)piperidine), a sigma receptor agonist, in the rat spinal cord were shown to represent two populations of recognition sites. Inhibition studies revealed that ligands with high affinity for the PCP receptor (MK-801 and PCP) were potent competitors at 3H-TCP binding sites whereas the putative sigma receptor ligands (+/-)pentazocine and haloperidol were potent competitors at (+)3H-3-PPP binding sites. The autoradiographic distribution of 3H-TCP and (+)3H-3-PPP binding sites in adjacent sections of rat spinal cord demonstrated the occurrence of two distinct populations of binding sites. 3H-TCP binding sites were localized primarily in laminae I and II in cervical and thoracic spinal segments. Binding sites in lamina I decreased in density along a rostral to caudal gradient in the spinal cord. The highest density of (+)3H-3-PPP binding sites was found in the ventral horn (lamina VIII and IX) and over perikarya in dorsal root ganglia. Significantly elevated densities of (+)3H-3-PPP binding sites were also found in lamina X within thoracic and lumbar segments and in the intermediolateral cell column. The results of the present study show that PCP and sigma receptor binding sites are differentially localized in the rat spinal cord and suggest that separate binding sites exist for PCP and sigma agonists.
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PMID:Phencyclidine and sigma receptors in rat spinal cord: binding characterization and quantitative autoradiography. 254 51

Whole-cell voltage-clamp recording techniques were used to investigate the blockade of voltage-dependent K+ channels by phencyclidine (PCP) in cultured rat hippocampal neurons. All recordings were carried out in the presence of tetrodotoxin (1-2 microM) to eliminate Na+ currents. Step depolarization from a holding potential of -40 mV activated a slowly rising, minimally inactivating K+ current (IK). PCP (0.5-1000 microM) caused a reduction in the maximum conductance of IK [IC50(+30 mV), 22 microM] without altering its voltage dependency. The PCP block of IK diminished at depolarized potentials. Analysis according to the scheme of Woodhull (1973) suggested that block occurs via binding to an acceptor site (presumably within the channel pore) that senses 40-50% of the transmembrane electrostatic field. PCP had no effect on the kinetic properties of IK and the block failed to show use dependency, suggesting that PCP may bind to the IK channel via a hydrophobic mechanism not requiring open channels. For comparison, we also investigated the effect of PCP on the transient K+ current, IA, activated by step depolarization following a 200 msec prepulse to -90 mV (20 mM tetraethylammonium was present in the bathing solution to reduce IK). In contrast to the potent blocking action of PCP on IK, the drug only affected IA at high concentrations [IC50(+30 mV), 224 microM]. At concentrations causing substantial block (300-500 microM), PCP produced an acceleration in the IA inactivation rate, and, for brief (5-6 msec) depolarizing steps, the suppression of IA was use dependent. These observations suggest that PCP block of IA requires open channels. PCP reduced inward current responses induced by the excitatory amino acid agonist N-methyl-D-aspartate (NMDA) at substantially lower concentrations than those required for its effects on K+ channels [IC50(-60 mV), 0.45 microM]. The PCP-like dioxadrol stereoisomer dexoxadrol (10 microM) blocked NMDA-evoked inward current responses, while its behaviorally inactive enantiomer levoxadrol did not. Dexoxadrol and levoxadrol also blocked IK in a stereoselective fashion (IC50's, 73 and 260 microM, respectively), whereas the sigma ligands (+)- and (-)-SKF 10,047 and (+)-3-[3-hydroxyphenyl]-N-(1-propyl)piperidine [(+)-3-PPP] had little effect on the current (IC50's, greater than 300-500 microM). We conclude that PCP causes a selective, voltage-dependent block of IK in hippocampal neurons via a PCP- and not a sigma-type acceptor site.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Interaction of phencyclidine with voltage-dependent potassium channels in cultured rat hippocampal neurons: comparison with block of the NMDA receptor-ionophore complex. 255 61

The development of N-(1-[2-thienyl]-cyclohexyl)[3H]piperidine [( 3H]TCP) binding to phencyclidine (PCP) receptors in both brain homogenates and slices has been investigated in the rat. The specific binding sites for [3H]TCP in the homogenate were already detected at prenatal stages and steadily increased after birth. A similar developmental pattern was seen in the autoradiography of the [3H]TCP binding to the brain slice in which the distribution of the binding in the young is more homogeneous than that in adult. There was an increase in the Bmax without changes in the Kd of the [3H]TCP binding and there was no change in inhibition of the binding by TCP, PCP and D-(-)-2-amino-5-phosphonovalerate during postnatal maturation. These findings suggest an increase in the density with no change in the affinity of PCP receptors and the absence of a change in the interaction between the PCP and N-methyl-D-aspartate receptors in the developing rat forebrain.
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PMID:Embryonic and postnatal development of N-(1-[2-thienyl]cyclohexyl)[3H]piperidine binding sites in rat forebrain homogenates and slices. 255 72

Recent studies from our laboratory have provided evidence that multiple states of the phencyclidine (PCP) receptor exist. In addition, several compounds such as PCP and the novel anticonvulsant MK-801 were found to inhibit binding more potently in the presence of Mg2+ and L-glutamate (L-GLU) than when these agents were excluded from the binding assay. In the present study, a number of pharmacological compounds that have been suggested to interact within the N-methyl-D-aspartate (NMDA) receptor complex, including tricyclic antidepressants (TCAs), were examined for their ability to inhibit the binding of [3H]1-[1-(2-thienyl)cyclohexyl]piperidine [( 3H]TCP) in the absence or presence of Mg2+ and L-GLU. The TCAs imipramine, amitriptyline, and opipramol produced shallow inhibition curves in the absence of Mg2+ and L-GLU. Computer analysis of the binding data indicated that a two-component binding model described the data significantly better than a one-component model. In the presence of Mg2+ and L-GLU, the inhibition curves became steeper and were shifted to the right, and computer analysis of the binding data indicated that a one-component model adequately described the binding data. A series of other centrally active compounds, including several antipsychotics and antihistamines, the antiparkinsonian anticholinergic trihexyphenidyl and the antitussive dextromethorphan, were also found to be affected similarly by the inclusion of Mg2+ and L-GLU in the binding assay. Dextrorphan, in contrast to dextromethorphan, inhibited [3H]TCP binding more potently in the presence of Mg2+ and L-GLU. The present results suggest that the compounds that inhibit binding more potently in the absence of Mg2+ and L-GLU are interacting with the PCP receptor in a different manner from that of PCP and MK-801, because these open-channel blockers inhibit [3H]TCP binding more potently in the presence of Mg2+ and L-GLU. The data support previous findings that TCAs interact with the NMDA receptor complex and suggest that the compounds trihexyphenidyl and dextromethorphan, which have been shown to block NMDA-mediated neurotoxicity, may produce their effects through an interaction with the PCP receptor, albeit by a different mechanism from that of open-channel blockers.
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PMID:Tricyclic antidepressants and dextromethorphan bind with higher affinity to the phencyclidine receptor in the absence of magnesium and L-glutamate. 256 80

Samples of human liver and placenta microsomes were analyzed for their in vitro hydroxylation capabilities using phencyclidine, [PCP, 1-(1-phenylcyclohexyl)piperidine] as substrate. Microsomes were prepared from full-term placentas (cesarean deliveries under epidural anesthesia) and from histologically normal liver specimens (staging laparotomies for Hodgkin's disease). Three different hydroxylated PCP metabolites were assayed including 1-(1-phenyl-3-hydroxycyclohexyl)piperidine (3-OH-cyclo-PCP), 1-(1-phenyl-4-hydroxycyclohexyl)piperidine (3-OH-cyclo-PCP), 1-(1-phenyl-4-hydroxycyclohexyl)piperidine (4-OH-cyclo-PCP), and 1-(1-phenylcyclohexyl)-4-hydroxypiperidine (4-OH-pip-PCP). The mean amounts of in vitro microsomal hydroxylation of PCP at the three different positions of the PCP ring varied considerably between individual samples of both liver and placenta. The placenta hydroxylated PCP but not as effectively as liver. Evidence for independent hydroxylation of PCP to 3-OH-cyclo-PCP was comparable to 4-OH-cyclo-PCP and 4-OH-pip-PCP. The formation of 3-OH-cyclo-PCP by the liver was enhanced in tobacco smokers. The formation of 4-OH-cyclo-PCP by the liver was negatively correlated with the stage of Hodgkin's disease even though the liver was free of disease in 11 of 12 subjects.
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PMID:Some factors affecting phencyclidine biotransformation by human liver and placenta. 256 7

1-Phenylcyclohexylamine (PCA), an analog of phenyclidine (PCP) in which the piperidine ring is replaced by a primary amino group, and its conformationally restricted analog 1,1-pentamethylenetetrahydroisoquinoline (PM-THIQ) were potent anticonvulsants in the mouse maximal electroshock (MES) seizure test (ED50 values, 7.0 and 14.3 mg/kg, respectively). At higher doses, the drugs caused motor impairment (TD50 values, 16.3 and 43.0 mg/kg) and blocked the behavioral effects and lethality of i.p. injected N-methyl-D-aspartate (NMDA) (ED50 values, 36.3 and 127 mg/kg). The separation in potencies in the MES seizure and motor toxicity tests of PCA and PM-THIQ contrasts with PCP which was equally potent in both tests. Several compounds that were structurally related to PM-THIQ (N-ethyl-PCA, 2-methyl-PCA, N-methyl-PM-THIQ, tetrahydroisoquinoline and benzylamine) also blocked MES seizures and caused motor impairment, but failed to show as great a separation between MES anticonvulsant activity and motor toxicity. None of the compounds protected against seizures induced by the chemoconvulsant pentylenetetrazol at doses that lacked motor toxicity. The drugs were also evaluated for their ability to displace [3H]-1-[1-(2-thienyl)-cyclohexyl]piperidine from binding to high affinity acceptor sites (presumably on NMDA receptor-coupled channels) in rat brain homogenates. The rank order of potencies in the binding assay was similar to that in the behavioral tests, except for 2-methyl-PCA which was behaviorally more potent than expected.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Anticonvulsant activities of 1-phenylcyclohexylamine and its conformationally restricted analog 1,1-pentamethylenetetrahydroisoquinoline. 265 75

Phencyclidine (PCP) inhibits dopamine (DA) uptake and acts as a noncompetitive N-methyl-D-aspartate antagonist by binding to PCP receptors. The PCP analog N-[1-(2-benzo(b)thiophenyl) cyclohexyl]piperidine (BTCP, GK13) is a potent DA uptake inhibitor, but has low affinity for PCP receptors. The behavioral effects of BTCP were compared with those of PCP, ketamine, MK-801 and cocaine. In mice, BTCP, like cocaine, produced locomotion, sniffing and gnawing; haloperidol blocked these effects. PCP, ketamine and MK-801 produced locomotion, sniffing, swaying and falling. PCP, ketamine and MK-801 produced generalization in rats discriminating either cocaine, PCP or MK-801 from saline. Like cocaine, BTCP produced generalization in cocaine-discriminating rats only; haloperidol partially antagonized this effect. In pigeons, PCP-like catalepsy was produced by ketamine and MK-801, but not by BTCP. N-methyl-D-aspartate-induced convulsions in mice were antagonized by PCP, ketamine and MK-801, but not by BTCP or cocaine. Thus, BTCP shared only cocaine-like behavioral effects with PCP, ketamine and MK-801. A DA antagonist reduced the effects of BTCP. Therefore, the cocaine-like behavioral effects of BTCP may be mediated primarily by DA uptake mechanisms. However, PCP receptors, but not DA uptake mechanisms, may mediate the cocaine-like behavioral effects of PCP, ketamine and MK-801, because their order of potency in producing these effects (MK-801 greater than PCP greater than ketamine) is consistent with their potency order at PCP receptors, but not at DA uptake sites.
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PMID:The phencyclidine (PCP) analog N-[1-(2-benzo(B)thiophenyl) cyclohexyl]piperidine shares cocaine-like but not other characteristic behavioral effects with PCP, ketamine and MK-801. 267 16

Hallucinogenic drugs are unique in that they produce the desired hallucinogenic effects at what are considered non-toxic doses. The hallucinogenic drugs can be categorised into 4 basic groups: indole alkaloid derivatives, piperidine derivatives, phenylethylamines and the cannabinols. The drugs reviewed include lysergic acid diethylamide (LSD), phencyclidine (PCP), cocaine, amphetamines, opiates, marijuana, psilocybin, mescaline, and 'designer drugs.' Particularly noteworthy is that each hallucinogen produces characteristic behavioural effects which are related to its serotonergic, dopaminergic or adrenergic activity. Cocaine produces simple hallucinations, PCP can produce complex hallucinations analogous to a paranoid psychosis, while LSD produces a combination of hallucinations, pseudohallucinations and illusions. Dose relationships with changes in the quality of the hallucinatory experience have been described with amphetamines and, to some extent, LSD. Flashbacks have been described with LSD and alcohol. Management of the intoxicated patient is dependent on the specific behavioural manifestation elicited by the drug. The principles involve differentiating the patient's symptoms from organic (medical or toxicological) and psychiatric aetiologies and identifying the symptom complex associated with the particular drug. Panic reactions may require treatment with a benzodiazepine or haloperidol. Patients with LSD psychosis may require an antipsychotic. Patients exhibiting prolonged drug-induced psychosis may require a variety of treatments including ECT, lithium and l-5-hydroxytryptophan.
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PMID:Clinical features and management of intoxication due to hallucinogenic drugs. 268 30


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