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)

Phencyclidine (PCP)-induced behaviors were compared with 5-methoxy-N,N-dimethyltryptamine (5-MeODMT)- and p-chloroamphetamine-induced behaviors in rats pretreated with ritanserin or 5,7-dihydroxytryptamine (5,7-DHT) in order to investigate whether PCP interacts with 5-hydroxytryptamine2 (5-HT2) receptors. Head-twitch and wet-dog shake induced by p-chloroamphetamine, a 5-HT releaser, and head-twitch induced by PCP were blocked completely by pretreatment with ritanserin, a specific 5-HT2 receptor blocker, but other behaviors induced by p-chloroamphetamine, PCP and 5-MeODMT, a 5-HT agonist, were not. The intensity of head-weaving, turning, backpedalling and hind-limb abduction induced by 5-MeODMT and the intensity of head-weaving, turning and head-twitch induced by PCP were markedly greater in the rats 2 weeks after the 5,7-DHT, a 5-HT neurotoxin-injection. Contrarily, 5-HT-mediated behaviors induced by p-chloroamphetamine were attenuated in the 5,7-DHT-treated rats. 5,7-DHT-treatment increased the number of 5-HT1 ([3H]-5-HT), 5-HT2 ([3H]ketanserin) and PCP ([3H]PCP) binding sites in the synaptic membrane of rat brain, but decreased the brain level of 5-HT (41% of control). These results may indicate that PCP as a 5-HT2 agonist induces head-twitch via 5-HT2 receptors, and that PCP induces head-weaving and turning via 5-HT1 receptors and/or some other mechanisms in rats.
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PMID:Potentiation in phencyclidine-induced serotonin-mediated behaviors after intracerebroventricular administration of 5,7-dihydroxytryptamine in rats. 282 56

This study was designed to assess whether phencyclidine (PCP)-induced head-twitch was antagonized by ritanserin, a selective serotonin (5-HT2) receptor antagonist, in mice and rats to confirm the involvement of 5-hydroxytryptamine (5-HT) neurons in PCP actions in comparison with 5-methoxy-N,N-dimethyltryptamine (5-MeODMT)-induced behavior. PCP (7.5, 10 and 12.5 mg/kg, i.p.)-induced head-twitch was completely antagonized by ritanserin (1 mg/kg, s.c.) in mice and rats, and 5-MeODMT (2 and 4 mg/kg, i.p.)-induced head-twitch was also completely antagonized by ritanserin in mice. PCP and 5-MeODMT induced head-weaving in mice after ritanserin treatment, but this did not occur in rats. In rats, 5-MeODMT failed to induce head-twitch. These results suggest that PCP-induced head-twitch response in rats is developed via 5-HT2 receptors and it is a useful 5-HT2 receptor model, while 5-MeODMT-induced head-weaving in rats is developed via 5-HT1 receptors and is a useful 5-HT1 receptor model.
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PMID:Phencyclidine-induced head-twitch responses as 5-HT2 receptor-mediated behavior in rats. 310 30

This study was designed to assess whether phencyclidine (PCP)-induced behaviors in rats were potentiated after two days' withdrawal from chronic methysergide (a 5-HT2 receptor blocker) treatment (10 mg/kg per day i.p. for 12 days), in order to confirm the involvement of 5-hydroxytryptamine (5-HT) neurons in PCP actions. The PCP (10 mg/kg)-induced behaviors (head-twitch, head-weaving, turning and backpedalling) were attenuated by successive pretreatment with PCP (10 mg/kg per day i.p. for 12 days), while PCP- and 5-methoxy-N,N-dimethyltryptamine (2 mg/kg)-induced head-twitch increased significantly after the repeated methysergide treatment was stopped. The development of tolerance to PCP-induced head-twitch was antagonized by pretreatment with methysergide. Furthermore, Scatchard plots of specific [3H]ketanserin binding at the 5-HT2 receptors and [3H]PCP binding at the PCP receptors in the methysergide group revealed significant increases in binding capacity (Bmax) with no change in affinity (Kd). On the contrary, after development of tolerance to PCP, there were significant decreases in Bmax of [3H]ketanserin binding with no change in affinity. PCP can thus displace [3H]ketanserin at the 5-HT2 receptor site, but not [3H]5-HT at the 5-HT1 receptor site. These facts indicate that PCP may produce head-twitch via an agonistic interaction with 5-HT2 receptor sites.
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PMID:Phencyclidine-induced head-twitch response in rats treated chronically with methysergide. 355 94

This study was designed to determine the action sites of phencyclidine (PCP) involved in the development of behaviors such as head-weaving, immobility, turning and backpedalling in relation to dopaminergic and serotonergic neuronal functions. Injection of PCP into the caudate nucleus or prefrontal cortex dose-dependently produced head-weaving, although the injection of PCP into the nucleus accumbens failed to produce head-weaving. The intensity of head-weaving induced by injection of PCP into the prefrontal cortex was relatively high when compared to that induced by injection of PCP into the caudate nucleus or lateral ventricle. Pretreatment with p-chlorophenylalanine (300 mg/kg), a serotonin (5-HT) synthesis inhibitor, attenuated head-weaving induced by injection of PCP into the prefrontal cortex. Injection of PCP (50-100 micrograms) into the prefrontal cortex also produced immobility for 5 min post-injection. Rats pretreated with pimozide (1 mg/kg), a dopamine (DA) antagonist, also produced immobility after the injection of PCP into the prefrontal cortex and this effect was attenuated by pretreatment with ritanserin, a 5-HT2 receptor antagonist. On the other hand, pretreatment with methamphetamine attenuated PCP (5 and 7.5 mg/kg)-induced turning and backpedalling but not head-weaving. Pretreatment with large doses of apomorphine, a DA agonist, also greatly attenuated PCP (7.5 mg/kg)-induced behaviors, i.e. head-weaving, turning and backpedalling. These effects of DA agonists were prevented by haloperidol (0.25 mg/kg), a DA antagonist. These results suggest that PCP-induced turning and backpedalling may be mediated by reducing dopaminergic transmission, although PCP-induced head-weaving and immobility may be produced by increasing serotonergic transmission in the prefrontal cortex.
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PMID:Role of dopaminergic and serotonergic neuronal systems in the prefrontal cortex of rats in phencyclidine-induced behaviors. 357 18

Chronic phencyclidine (PCP) administration has been shown to produce tolerance to a number of its pharmacological actions. We have suggested that PCP interacts with the 5-HT2 receptors since it inhibits [3H]spiperone binding to 5-HT2 receptors in vitro. In the present study, we investigated whether methysergide (a 5-HT2 receptor blocker) induces the precipitated withdrawal syndrome in PCP-tolerant rats. The body weight of the rats in the abrupt and precipitated withdrawal groups was significantly lower 5 days and 1-5 days after withdrawal, respectively, than that in the control group. Furthermore, other typical precipitated abstinence syndrome characteristics such as jumping, wet-dog shake and ptosis were also observed in the precipitated withdrawal group. These results suggest that PCP produces its behavioral effects via an agonistic interaction with 5-HT2 receptor sites and that our method may be very useful for the development of a rat model for studying physical dependence on PCP.
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PMID:Methysergide-induced precipitated withdrawal syndrome in phencyclidine-dependent rats. 376 58

We investigated whether risperidone, a 5-HT2/dopamine-D2 receptor antagonist, inhibits the development of tolerance and supersensitivity to PCP and whether subacute administration of PCP with risperidone affects the [3H]MK-801 binding in rat brain, in comparison with dopamine-D2 receptor antagonist haloperidol and 5-HT2 receptor antagonist ritanserin. In rats treated with PCP (10 mg/kg, i.p.) for 14 days, PCP (10 mg/kg, i.p.)-induced hyperlocomotion, rearing and sniffing were potentiated (supersensitivity), and head-weaving, head-twitch, backpedalling and turning were diminished (tolerance). The development of supersensitivity to PCP was blocked by oral co-administration of risperidone (2.4 mg/kg, p.o.) and haloperidol (1.0 mg/kg, p.o.) for 14 days, but not ritanserin (10 mg/kg, p.o.) and risperidone (0.8 mg/kg, p.o.), while no drugs prevented the development of tolerance to PCP. Both risperidone (2.4 mg/kg, p.o.) and haloperidol (1.0 mg/kg, p.o.) also inhibited the cross-supersensitivity to methamphetamine (MAP; 2.5 mg/kg, i.p.)-induced rearing in rats treated with PCP for 14 days. The profiles of [3H]MK-801 binding in discrete brain areas did not change after subacute administration of PCP alone or in combination with risperidone, haloperidol or ritanserin for 14 days. Therefore, it is suggested that subacute administration of PCP may cause functional changes in the dopaminergic neuronal transmission under conditions where the binding of [3H]MK-801 in discrete brain areas is unchanged, and that co-administration of risperidone may block these PCP-induced changes in neuronal function.
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PMID:Risperidone prevents the development of supersensitivity, but not tolerance, to phencyclidine in rats treated with subacute phencyclidine. 753 75

In experiments in rats, by the use of single-cell recordings from midbrain dopamine (DA) neurons of the ventral tegmental area (VTA), the systemic administration of the schizophrenomimetic N-methyl-D-aspartate receptor antagonists phencyclidine (PCP) or dizocilpine (MK-801) caused an increased firing rate but reduced the variability of firing in VTA DA neurons. Burst firing was increased in cells predominantly located in the paranigral nucleus, a subdivision of the VTA largely projecting to the nucleus accumbens and other limbic regions, but reduced in DA cells predominantly located in the parabrachial pigmented nucleus, another subdivision of the VTA that projects largely to the prefrontal cortex (PFC). Thus, a severely impaired signal-to-noise ratio within the PFC DA projection was obtained, concomitant with an overactive mesolimbic DA system. The administration of high doses of ritanserin or atypical neuroleptics with prominent serotonin (5-hydroxytrypyamine) 5-HT2 receptor antagonist action, such as clozapine or amperozide, produced preferential activation of the PFC DA projection. In contrast, the selective D2 receptor antagonist raclopride caused a greater activation of the subcortical than cortical DA projections, as assessed by microdialysis experiments in vivo from our laboratory. Adding ritanserin treatment to raclopride markedly enhanced the raclopride-induced increase in DA levels in the medial PFC, an effect probably mediated by augmentation of the raclopride-induced increase in the burst firing of meso-cortical DA neurons, but failed to affect the action of raclopride on striatal DA levels.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Mode of action of atypical neuroleptics in relation to the phencyclidine model of schizophrenia: role of 5-HT2 receptor and alpha 1-adrenoceptor antagonism [corrected]. 773 Apr 96

N,N-Dipropyl-2-[4-methoxy-3-(2-phenylethoxy)phenyl]-ethylamine monohydrochloride (NE-100) is a selective and potent sigma receptor ligand. We investigated the effects of NE-100 on phencyclidine (PCP)-induced cognitive dysfunction in rats in a water maze task. NE-100 significantly shortened the PCP-induced prolonged swimming latency as did 1-(cyclopropylmethyl)-4-[2'(4"-fluorophenyl)-2'-oxoethyl]- piperidine monohydrobromide (Dup 734), 4-[2'-(4"-cyanophenyl)-2'-oxoethyl]-1-(cyclopropyl-methyl)pi peridine (XJ 448), alpha-(4-fluorophenyl)-4-(5-fluoro-2-pyrimidinyl)-1-piperazine butanol (BMY 14802) and rimcazole, all of which are sigma receptor ligands and possibly antagonists. Ritanserin, a 5-HT2 receptor antagonist, also showed a tendency to shorten swimming latencies. Latencies of haloperidol-, cis-N-(1-benzyl-2-methyl-pyrrolidin-3-yl)-2-methoxy-5-chloro-4-met hyl- aminobenzamide (YM-09151-2)- and sulpiride-, dopamine D2 receptor antagonists, treated groups did not differ from that seen in the PCP-treated group. Thus, PCP-induced cognitive dysfunction may be improved by sigma receptor ligands.
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PMID:Effect of NE-100, a novel sigma receptor ligand, on phencyclidine-induced cognitive dysfunction. 782 67

d-Amphetamine (DEX) and phencyclidine (PCP) increased motor activity in rats as measured in automated activity cages. Analysis of the stimulation indicated that both drugs increased horizontal activity (total activity), locomotion, and peripheral activity. However, DEX increased while PCP decreased the incidence of rearing. The ability of different drugs to antagonise DEX- and PCP-induced increases in total activity (called stimulation) was measured. Dopamine (DA) D1 receptor antagonists (SCH23390, NNC-01-0112) were 7-8 times more potent in blocking DEX than PCP. DA D2 receptor antagonists (raclopride, remoxipride, haloperidol) were only 1-2 times more potent against DEX-induced stimulation. Nonselective DA receptor antagonists were also tested. Chlorpromazine was more potent against DEX than against PCP. Buspirone and sertindole were slightly more potent in blocking PCP than DEX. Ritanserin (5-HT2 receptor antagonist) was inactive against both stimulants. 8-OH-DPAT (5-HT1A receptor agonist) potentiated the stimulant effects of DEX and PCP. Prazosin (alpha 1-adrenergic receptor antagonist) partially blocked both DEX and PCP. Most drugs tested depressed spontaneous motor activity. Remoxipride and sertindole, however, caused very little depression even at doses several times higher than those needed to block DEX or PCP. The data show clear pharmacological differences between DEX- and PCP-induced stimulation.
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PMID:Dopamine receptor antagonists block amphetamine and phencyclidine-induced motor stimulation in rats. 809 Aug 16

We have previously found that repeated phencyclidine (PCP) treatment enhances the immobility induced by forced swimming and suggested that this behavioral change could be used as a model of the negative symptoms, particularly depression, of schizophrenia. The present study attempted to examine the effects of antidepressants on the depressive states (immobility) induced by forced swimming in mice repeatedly treated with PCP, compared with those in mice repeatedly treated with saline. In mice repeatedly treated with saline, desipramine (5 and 10 mg/kg) and imipramine (5 and 10 mg/kg) significantly attenuated immobility, whereas mianserin (5-20 mg/kg) and clomipramine (10 and 50 mg/kg) had no affect. In mice repeatedly treated with PCP, the enhancing effect of PCP on immobility was attenuated by mianserin (5-20 mg/kg) at doses which did not have any effect in saline-treated mice, and by desipramine at higher doses (20 and 50 mg/kg). However, imipramine (5-20 mg/kg) and clomipramine (10-50 mg/kg) did not affect PCP-induced enhancement of immobility. In the biochemical study, the content of 5-hydroxyindoleacetic acid (5-HIAA) and the 5-HIAA/5-hydroxytryptamine (5-HT) ratio in the prefrontal cortex in mice repeatedly treated with PCP, but not with saline, following the forced swimming test were significantly increased, compared with those in the corresponding control mice (which did not perform the test). The present findings suggest that the depressive states induced by the forced swimming in mice repeatedly treated with PCP are less sensitive to acute treatment with tricyclic antidepressants, and this may be due to increase in 5-HT turnover. Antidepressants such as mianserin, which have the 5-HT2 receptor antagonist properties, may be useful for the treatment of negative symptoms of schizophrenia.
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PMID:Effects of antidepressants on phencyclidine-induced enhancement of immobility in a forced swimming test in mice. 914 63


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