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)

Following a single dose of phencyclidine (PCP) striatal tyrosine hydroxylase (TH) activity was decreased 42% 15 min after PCP administration, but returned toward baseline levels by 45 min post-drug. Twenty-four hours after the 30th dose of PCP, TH activity remained depressed when compared to the chronic slaine controls. TH activity was not further depressed 15 or 45 min after the 31st dose of PCP.
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PMID:Effects of acute and chronic administration of phencyclidine on tyrosine hydroxylase activity in rat striatum. 610 63

Low doses of the uncompetitive N-methyl-D-aspartate (NMDA) receptor antagonist dizocilpine (MK-801) induce locomotor stimulation in mice, whereas higher doses are associated with ataxia, stereotyped behaviors and catalepsy. We investigated the role of dopamine receptors and presynaptic dopamine neurons in the locomotor effects of dizocilpine. For comparison, we studied several other drugs that induce locomotor stimulation in mice. Pretreatment of male mice with haloperidol (0.1 mg/kg, i.p.) completely prevented the stimulation of normally coordinated locomotion induced by a non-intoxicating dose of dizocilpine (0.1 mg/kg, i.p.); haloperidol also attenuated the locomotor stimulation produced by phencyclidine (PCP, 1 and 2 mg/kg, i.p.), d-amphetamine (2 and 5 mg/kg, i.p.) and diazepam (0.5 mg/kg, i.p.). Haloperidol (doses up to 2.5 mg/kg) did not attenuate the ataxia and decreased locomotion induced by higher doses of dizocilpine (1 and 2 mg/kg). The active cis isomer of flupenthixol (0.5 mg/kg, i.p.), an antagonist of both D1 and D2 dopamine receptors, also diminished the stimulant actions of all of the test drugs, whereas its inactive trans form did not. The selective D1 antagonist R(+/-)-SCH 23390 (0.1 mg/kg) and the selective D2 antagonist raclopride (1 mg/kg) had little effect on the stimulatory effect of dizocilpine, although they did reduce the stimulation produced by PCP, d-amphetamine and diazepam. However, pretreatment with a combination of R(+/-)SCH 23390 and raclopride completely prevented dizocilpine-induced locomotor stimulation. Pretreatment with alpha-methyl-p-tyrosine (AMPT, 50 and 250 mg/kg), an inhibitor of tyrosine hydroxylase, or with 6-hydroxydopamine (6-OH-DA, 50 micrograms, i.c.v.), a neurotoxin that destroys brain dopaminergic and noradrenergic neurons, did not attenuate the locomotor stimulation induced by dizocilpine, although these treatments did reduce the stimulant effects of d-amphetamine. In AMPT or 6-OH-DA pretreated mice, haloperidol (0.125 mg/kg) prevented the stimulatory effect of dizocilpine. These results support a role for dopamine receptors in the stimulation of normally coordinated locomotion by dizocilpine. However, the locomotor stimulant effect of dizocilpine, unlike that of d-amphetamine, can be expressed in the presence of D1 or D2 dopamine receptor blockade and does not appear to be dependent on intact presynaptic mechanisms.
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PMID:Effects of D1 and D2 dopamine receptor antagonists and catecholamine depleting agents on the locomotor stimulation induced by dizocilpine in mice. 856 5

Place conditioning paradigms are widely used for determining the motivational properties of drugs. Phencyclidine (PCP) has been a common drug of abuse during the past two decades and has a rewarding effect in animals. However, PCP produces place aversion in the conditioned place preference (CPP) task in animals. Here, we report the possible neuronal mechanisms of PCP-induced place aversion and preference in the CPP task in rodents. In naive rats and mice, PCP dose-dependently produced place aversion and PCP had a significant effect at the doses of 4 and 8 mg/kg in rats and mice, respectively. The aversive effect of PCP (4 mg/kg) in rats was significantly attenuated by ritanserin (3 and 10 mg/kg), a serotonin 15-HT2) receptor antagonist whereas the lesion of serotonergic (5-HTergic) neurons by 5,7-dihydroxytryptamine (100 micrograms i.c.v.) and alpha-methyl-rho-tyrosine (AMPT; 100 mg/kg), a tyrosine hydroxylase inhibitor, did not affect the aversive effect of PCP. In rats pretreated with PCP (10 mg/kg/day) for 14 days, tolerance was developed to PCP (4 mg/kg)-induced place aversion. In rats and mice pretreated with PCP (10 mg/kg/day) for 28 days, however, PCP dose-dependently produced place preference but not aversion. The preferred effect of PCP (8 mg/kg) in mice preteated with PCP (10 mg/kg/day for 28 days) was significantly attenuated by AMPT (100 mg/kg) and 6-hydroxydopamine (100 micrograms i.c.v.) a dopaminergic (DAergic) neurotoxin, but not by DSP-4 (30 mg/kg), a noradrenergic neurotoxin and ritanserin. In mice pretreated with methamphetamine (1 mg/kg/day) for 14 days, PCP (8 mg/kg) produced place preference. These findings suggest that 5-HTergic and DAergic systems are involved in the PCP-induced place aversion and preference, respectively, and some changes in the neuronal systems including DAergic systems, induced by repeated PCP treatment play a critical role in the addiction of PCP.
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PMID:Neuronal mechanisms of phencyclidine-induced place aversion and preference in the conditioned place preference task. 981 6

There is considerable evidence that drug reward and brain stimulation reward (BSR) share common neural substrates. Although it is known that exposure to drugs of abuse causes a variety of molecular changes in brain reward systems, little is known about the molecular consequences of BSR. We report that repeated exposure to rewarding stimulation of the medial forebrain bundle (MFB) selectively decreases expression of GluR1 (an AMPA receptor subunit) in the VTA, without effect on expression of several other proteins (GluR2, NMDAR1, tyrosine hydroxylase). This effect of BSR on GluR1 expression is opposite of that caused by intermittent exposure to cocaine and morphine, which are known to elevate GluR1 expression in the VTA. Considering that elevated GluR1 expression in the VTA has been associated with increased sensitivity to drug reward, the finding that BSR and drugs of abuse have opposite effects on GluR1 expression in this region may provide an explanation for why the reward-related effects of many drugs (cocaine, morphine, amphetamine, PCP, nicotine) do not sensitize with repeated testing in BSR procedures that quantify reward strength.
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PMID:Repeated exposure to rewarding brain stimulation downregulates GluR1 expression in the ventral tegmental area. 1142 7

We investigated the molecular mechanisms of development to phencyclidine (PCP)-induced rewarding effect by using tyrosine hydroxylase (TH) heterozygous (TH(+/-)) mice. PCP (8 mg/kg) induced the place preference in wild-type mice pretreated with PCP (10 mg/kg/day for 28 days). The place preference induced by PCP is attenuated by 6-hydroxydopamine, a dopaminergic neurotoxin, and (+) SCH-23390, a dopamine-D1 receptor antagonist, but not by DSP-4, a noradrenergic neurotoxin, and (-) sulpiride, a dopamine-D2 receptor antagonist. In TH(+/-) mice pretreated with PCP (10 mg/kg/day for 28 days), no PCP (8 mg/kg)-induced place preference was observed. In wild-type mice pretreated with PCP, the levels of cAMP, cAMP response element binding protein (CREB), and c-fos mRNA in the nucleus accumbens were increased. The levels of cAMP, CREB, and c-fos mRNA in the nucleus accumbens were not increased by the same treatment schedule of PCP in TH(+/-) mice. These findings suggest that changes in dopaminergic and/or cAMP signal cascades induced by repeated PCP treatment play an important role in the development of PCP-induced rewarding effect.
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PMID:Involvement of signal transduction cascade via dopamine-D1 receptors in phencyclidine dependence. 1554 1

N-methyl-D-aspartate (NMDA) receptor antagonists can elicit symptoms in humans that resemble those seen in schizophrenic patients. Rodents manifest locomotor and stereotypic behaviors when treated with NMDA receptor antagonists such as phencyclidine (PCP) or dizocilpine maleate (MK-801); these behaviors are usually associated with an activated dopamine system. However, recent evidence suggests that increased glutamatergic transmission mediates the effects of these NMDA receptor antagonists. The role of dopamine in PCP- and MK-801-induced behavior (eg hyperlocomotion) remains unclear. We used dopamine-deficient (DD) mice in which tyrosine hydroxylase is selectively inactivated in dopaminergic neurons to determine whether dopamine is required for the locomotor and molecular effects of PCP and MK-801. DD mice showed a similar increase in locomotor activity and c-fos mRNA induction in the striatum in response to these NMDA receptor antagonists as control mice. Restoration of dopamine signaling in DD mice enhanced their locomotor response to PCP and MK-801. Administration of LY379268, a group II metabotropic glutamate receptor agonist that inhibits glutamate release, blocked PCP- and MK-801-induced hyperlocomotion in both DD and control mice. These results suggest that glutamate, rather than dopamine, is required for the locomotor and molecular effects of NMDA receptor antagonists, but that glutamate and dopamine can act cooperatively.
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PMID:Dopamine is not required for the hyperlocomotor response to NMDA receptor antagonists. 1568 82

This study examined how perinatal phencyclidine (PCP) treatment would affect dopamine D2 receptor and dopamine transporter (DAT) binding at different stages after treatment cessation. Female rat pups received injections of PCP (10 mg/kg, s.c.) or saline on postnatal day (PN)7, 9 and 11. D2 receptor and transporter binding was examined at four time-points (PN12, 18, 32 and 96) following injections. PCP treatment altered D2 receptor binding throughout development, with a final end-point of 22-33% decreased binding at adulthood in the nucleus accumbens and caudate putamen (P < 0.01), accompanied by a small but significant increase in DAT binding in the caudate putamen. Tyrosine hydroxylase mRNA expression was also significantly increased by 25% (P < 0.05) in the ventral tegmental area of adult rats, suggesting that this model may produce a long-term increase in dopamine output. This study demonstrates that early insult to the brain from NMDA receptor hypofunction alters the dopaminergic system at different stages of development.
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PMID:Altered dopamine receptor and dopamine transporter binding and tyrosine hydroxylase mRNA expression following perinatal NMDA receptor blockade. 1825 31

From the VGF precursor protein originate several low molecular weight peptides, whose distribution in the brain and blood circulation is not entirely known. Among the VGF peptides, those containing the N-terminus portion were altered in the cerebro-spinal fluid (CSF) and hypothalamus of schizophrenia patients. "Hence, we aimed to better investigate the involvement of the VGF peptides in schizophrenia by studying their localization in the brain regions relevant for the disease, and revealing their possible modulations in response to certain neuronal alterations occurring in schizophrenia". We produced antibodies against different VGF peptides encompassing the N-terminus, but also C-terminus-, TLQP-, GGGE- peptide sequences, and the so named NERP-3 and -4. These antibodies were used to carry out specific ELISA and immunolocalization studies while mass spectrometry (MS) analysis was also performed to recognize the intact brain VGF fragments. We used a schizophrenia rat model, in which alterations in the prepulse inhibition (PPI) of the acoustic startle response occurred after PCP treatment. In normal rats, all the VGF peptides studied were distributed in the brain areas examined including hypothalamus, prefrontal cortex, hippocampus, accumbens and amygdaloid nuclei and also in the plasma. By liquid chromatography-high resolution mass, we identified different intact VGF peptide fragments, including those encompassing the N-terminus and the NERPs. PCP treatment caused behavioral changes that closely mimic schizophrenia, estimated by us as a disruption of PPI of the acoustic startle response. The PCP treatment also induced selective changes in the VGF peptide levels within certain brain areas. Indeed, an increase in VGF C-terminus and TLQP peptides was revealed in the prefrontal cortex (p < 0.01) where they were localized within parvoalbumin and tyrosine hydroxylase (TH) containing neurons, respectively. Conversely, in the nucleus accumbens, PCP treatment produced a down-regulation in the levels of VGF C-terminus-, N-terminus- and GGGE- peptides (p < 0.01), expressed in GABAergic- (C-terminus/GGGE) and somatostatin- (N-terminus) neurons. These results confirm that VGF peptides are widely distributed in the brain and modulated in specific areas involved in schizophrenia.
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PMID:Profiles of VGF Peptides in the Rat Brain and Their Modulations after Phencyclidine Treatment. 2862 90