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)

The effect of salmon calcitonin (SCT) on the lethality of quinolinic acid (QA), an endogenous excitatory amino acid, was investigated in relation to the excitatory amino acid receptor/ion channel complex. SCT increased the LD50 value of QA in a bell-shaped fashion, but the difference was not significant. The non competitive N-methyl-D-aspartate (NMDA) receptor antagonists MK-801 and phencyclidine (PCP) inhibited QA lethality dose-dependently. SCT potentiated the inhibitory effects of these antagonists. The competitive and glycine site antagonists 3-((+-)-2-carboxypiperazin-4-yl)propyl-1-phosphonic acid (CPP) and 7-chlorokynurenic acid (7ClK), respectively, inhibited QA lethality in a dose-dependent fashion. SCT did not potentiate the effect of either drug. These results suggest that SCT inhibits NMDA receptors by interacting with Ca ion channel.
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PMID:Effect of salmon calcitonin on the lethality of quinolinic acid, an excitatory amino acid. 133 50

Diseases caused by cytomegalovirus (CMV) and pneumonia due to pneumocytis carinii (PCP) are problematic complications after allogeneic heart transplantation. Recipients of CMV-seropositive donors have a higher morbidity of CMV. By using an anti-CMV-immunoglobulin preparation in routine prophylaxis the incidence of CMV disease after heart transplantation could be reduced significantly. Ganciclovir 10 mg/kg is administered for treatment of CMV disease for at least 14 days. Recent investigations show that a prophylactic administration of ganciclovir after heart transplantation is safe, and it reduces the incidence of CMV-induced illness in CMV-seropositive patients. The incidence of PCP after heart transplantation varies according to the literature between 1 and 13%. The onset of the disease is located mostly between the third and the fifth month after heart transplantation. An effective prophylaxis can be achieved by low dose cotrimoxazole (960 mg at two days per week in adults) within the first six postoperative months. Cases of PCP are treated by cotrimoxazole or pentamidine and are associated with a mortality up to 60%.
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PMID:[Incidence, prevention and therapy of cytomegalovirus and pneumocystis carinii infection after heart transplantation]. 133 22

In NGF-treated PC12 cells, nicotine-induced K+ release was measured with a K(+)-sensitive microelectrode. The K+ outflow via nicotinic ACh receptor cation channels was inhibited by various psychotomimetic sigma ligands in the sequence of PCP, dextromethorphan >> DTG, MK 801, (+)SKF10047 >> (+)3-PPP. The K+ release was not affected by the neuroleptic sigma ligand haloperidol nor by the calcium antagonist nifedipine. The results suggest that psychotomimetic sigma ligands inhibit nicotine-stimulated K+ flux by interacting with nicotinic, rather than via sigma 2 receptors.
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PMID:Inhibitory effects of psychotomimetic sigma ligands on nicotine-induced K+ flux from differentiated PC12 cells. 133 53

1. Phencyclidine (PCP) block of Ca2+ channel current in enzymatically dissociated neurones from the CA1 region of the adult guinea-pig hippocampus was studied using whole-cell voltage clamp techniques. Ca2+ channel current was recorded with 3 mM-Ba2+ as the charge carrier. Na+ currents were blocked with tetrodotoxin and K+ currents were eliminated by using tetraethylammonium and N-methyl-D-glucamine as the predominant extracellular and intracellular cations, respectively. 2. Peak Ca2+ channel current evoked by depolarization from -80 to -10 mV was reduced in a use-dependent fashion by PCP. The apparent forward and reverse rate constants for block at the depolarized voltage were 10(6) s-1 M-1 and 11-14 s-1, respectively. These values were at least 60 times faster than the corresponding rates at the resting voltage. The steady-state block produced by PCP increased in a concentration-dependent fashion with an IC50 of 7 microM. Other dissociative anaesthetic drugs were substantially weaker inhibitors of the current (tiletamine > dizocilpine (MK-801) > ketamine). 3. The Ca2+ channel current recorded under identical conditions in rat dorsal root ganglion neurones was less sensitive to blockade by PCP (IC50, 90 microM). 4. PCP block of the hippocampal Ca2+ channel current occurred in a voltage-dependent fashion with the fractional block decreasing at positive membrane potentials. Analysis indicated that the PCP blocking site senses 56% of the transmembrane electric field. 5. Analysis of tail currents recorded at -80 mV demonstrated that PCP does not affect the voltage-dependent or time-dependent activation or deactivation of the Ca2+ channel current. 6. The rate and extent of inactivation of the Ca2+ channel current was maximal at -10 mV and diminished at more positive potentials. Experiments with Ba(2+)-free external solution demonstrated that inactivation of the Ca2+ channels is largely voltage-dependent and is not affected by Ba2+ influx. 7. PCP markedly increased the apparent extent of inactivation of the Ca2+ channel current during prolonged voltage steps. This increase in apparent inactivation was more pronounced at depolarized potentials. Inactivation at -10 mV proceeded in two exponential phases; PCP had little effect on the fast decay phase and caused a moderate speeding of the slow decay phase. Although block of the activated state evolved on the same time scale as inactivation, the apparent rate of inactivation was not increased in a concentration-dependent fashion by PCP indicating that the block does not occur by a conventional open channel mechanism.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Phencyclidine block of calcium current in isolated guinea-pig hippocampal neurones. 133 8

High-affinity binding sites (apparent KD 2.87 nM) for [3H]desmethylimipramine ([3H]DMI), have been demonstrated and characterized in membrane preparations of bovine adrenal medulla. The binding of [3H]DMI improved upon pretreatment of the membrane with KCl and was saturable, sodium dependent, and potently inhibited by nisoxetine and imipramine. [3H]DMI binding was also inhibited by various phencyclidine (PCP)- and (or) sigma-receptor ligands, with the following order of potency: haloperidol > rimcazole > (-)-butaclamol > dextromethorphan > MK-801 > (+)-3-(3-hydroxyphenyl)-N-(1-propyl)piperidine ((+)-3-PPP) > PCP > N-(2-thienyl)cyclohexyl-3,4-piperidine (TCP) > (+)-SKF-10047 > (-)-SKF-10047. The inhibition produced by sigma ligands was not attributed to stimulation of either sigma 1- or sigma 2-receptors, owing to inactivity of the selective sigma-receptor ligands (+)-pentazocine and 1,3-di(2-tolyl)guanidine (DTG). The inhibition of [3H]DMI binding by sigma- and PCP-receptor ligands was not attributed to PCP1- or PCP2-receptor stimulation, owing to the decreased potency (100-fold) of these ligands in [3H]DMI assays compared with the affinity for brain PCP1 sites, and the ineffectiveness of the PCP2-ligand N-(1-(2-benzo(b)thiophenyl)cyclohexyl)piperidine (BTCP). Scatchard analysis of the inhibition by the sigma-ligands haloperidol and (+)-3-PPP, as well as the PCP1 receptor ligand MK-801, demonstrated noncompetitive interaction with the site bound by [3H]DMI. These studies indicate that bovine adrenomedullary membranes possess a specific receptor for the noradrenaline uptake inhibitor [3H]DMI, which is sensitive to allosteric modulation produced by PCP and sigma-ligands.
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PMID:Characterization of [3H]desmethylimipramine binding in bovine adrenal medulla: interactions with sigma- and (or) phencyclidine-receptor ligands. 133 74

Adult mice were exposed to long-term phencyclidine (PCP) treatments as animal models for psychosis. The drug was administered via osmotic minipumps implanted subcutaneously in the backs of the mice. The treatments for 7 days with 2.5 and 1 mg/d/mouse and the treatment for 3 days with 1 mg/d/mouse differentially affected the release of dopamine and D-aspartate from striatal and frontal cortical slices. In frontal cortical slices the potassium-stimulated release of dopamine increased, whereas the release of D-aspartate varied with the PCP dose. In striatal slices the release of D-aspartate was either decreased or unchanged, whereas the release of dopamine was mostly unchanged. The 3-day treatment with PCP followed by the 3-day period of withdrawal increased the potassium-stimulated release of dopamine from frontal cortical slices and decreased that from striatal slices. In brain slices from untreated mice PCP increased the release of dopamine in vitro, whereas the release of D-aspartate was not affected. It seems that PCP has region-specific effects on both dopaminergic and glutamatergic transmission in the central nervous system, and it may thus serve as an interesting experimental model for further research on psychosis.
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PMID:Phencyclidine treatments differentially affect dopamine and D-aspartate release from frontal cortical and striatal slices from mice. 134 50

The effect of (U-54494A) cis-3,4-dichloro-N-methyl-N-[2-(1-Pyrrolidinyl)- cyclohexyl] benzamide monohydrochloride, an excitatory amino acid antagonist, on N-methyl-D-aspartic acid (NMDA)- and K(+)-evoked release of [3H]acetylcholine [( 3H]ACh) from slices of striatum was investigated. For the purpose of comparison, MK 801, PCP, CGP 37849, CPP, phenytoin and diazepam were investigated under identical conditions. Both U-54494A and the excitatory amino acid antagonists blocked NMDA-evoked release of [3H]ACh but these compounds failed to inhibit K(+)-evoked release of this neurotransmitter. Phenytoin blocked both NMDA and K(+)-evoked release of [3H]ACh, whereas diazepam was ineffective under similar conditions. These observations indicate that excitatory amino acid antagonists, including U-54494A, may mediate their anticonvulsant effect by blocking the activity of NMDA receptors, diazepam by activating the benzodiazepine receptors and phenytoin by inhibiting the activity of various depolarizing agents.
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PMID:Modulation of release of acetylcholine from the striatum by a proposed excitatory amino acid antagonist U-54494A: comparison with known antagonists, diazepam and phenytoin. 134 10

The effects of N-methyl-D-aspartic acid (NMDA) and phencyclidine (PCP) on extracellular levels of dopamine (DA) and dihydroxyphenylacetic acid (DOPAC) in the striatum of the rat were studied using in vivo microdialysis. Intrastriatal infusion of NMDA produced a significant dose-dependent increase in extracellular DA and a decrease in concentrations of DOPAC. Whereas both 2-amino-5-phosphonovalerate (APV) and PCP antagonized the NMDA-induced increase in extracellular levels of DA, the effect on NMDA-induced changes in extracellular concentrations of DOPAC were different for the two compounds. The APV significantly attenuated the decrease in extracellular DOPAC produced by smaller concentrations of NMDA, whereas PCP did not prevent decrease in DOPAC produced by any concentrations of NMDA. Phencyclidine alone produced a dose-dependent increase in extracellular DA but had no effect on the extracellular concentration of DOPAC. This study demonstrated that PCP, at concentrations which did not produce an increase in extracellular DA, antagonized the effect of the NMDA on DA. The data also indicated that both APV and PCP antagonized the NMDA-evoked release of DA over a range of concentrations of NMDA, even though they did so by different mechanisms.
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PMID:The effect of phencyclidine and DL-2-amino-5-phosphonovaleric acid on N-methyl-D-aspartic acid induced changes in extracellular concentration of dopamine and DOPAC in the rat neostriatum. 134 11

A series of dioxolane analogues based on dexoxadrol ((4S,6S)-2,2-diphenyl-4-(2-piperidyl)-1,3-dioxolane) and etoxadrol ((2S,4S,6S)-2-ethyl-2-phenyl-4-(2-piperidyl)-1,3-dioxolane) were prepared and tested for their ability to displace [3H]TCP (1-[1-(2-thienyl)cyclohexyl]piperidine) from PCP (1-(1-phenylcyclohexyl)piperidine) binding sites in rat brain tissue homogenates. Qualitative structure-activity relationships within this series were explored through modifications of the three major structural units of dexoxadrol, the piperidine, 1,3-dioxolane, and aromatic rings of the molecule. N-Alkyl derivatives of dexoxadrol were found to be inactive, as were those analogues where the dioxolane ring was modified. Phenyl-substituted etoxadrol analogues were compared to similarly substituted PCP analogues and distinct differences were found in their structure-activity relationships suggesting that the aromatic rings in these two drug classes interact differently with the PCP binding sites. The replacement of the phenyl ring in etoxadrol by either a 2- or 3-thienyl ring led to compounds with affinity comparable to etoxadrol, and the replacement of the ethyl moiety on etoxadrol's dioxolane ring with propyl (7) or isopropyl (8) led to compounds which were more potent than etoxadrol or PCP. The most potent compound was (2S,4S,6S)-2-ethyl- 2-(1-chlorophenyl)-4-(2-piperidyl)-1,3-dioxolane (11), where a chlorine moiety was placed in the ortho position in the aromatic ring of etoxadrol. Its potency was comparable with TCP in vitro.
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PMID:Analogues of the dioxolanes dexoxadrol and etoxadrol as potential phencyclidine-like agents. Synthesis and structure-activity relationships. 134 51

The effects of phencyclidine (PCP) and NPC 12626 on punished responding were examined using a modified Geller-Seifter procedure in rats. Both drugs are known to antagonize N-methyl-D-aspartate (NMDA) receptor mediated neurotransmission, albeit at different sites on the NMDA receptor complex. Rats were trained to lever press for food reinforcement under a multiple schedule, with responding in one component reinforced under a fixed-interval 60-sec schedule, while each response in the other component resulted in both food and brief electric shock. Both PCP and NPC 12626 produced selective increases in punished responding, although the effects were not as large as those produced by chlordiazepoxide. Repeated daily administration of each of these drugs for 6 days resulted in increases in punished responding during different portions of the treatment. A 5 mg/kg dose of chlordiazepoxide produced increases over the last 2 days of administration. PCP (2 mg/kg) produced an increase only during the second session, whereas NPC 12626 (30 mg/kg) produced increases for all but the first and fifth days of the 6-day regimen. Both competitive and noncompetitive NMDA antagonists can have antipunishment effects in this model.
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PMID:Antipunishment effects of acute and repeated administration of phencyclidine and NPC 12626 in rats. 134 14


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