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PubMed1998

Rigid phencyclidine analogues. Binding to the phencyclidine and sigma 1 receptors.

Three phencyclidine (PCP) analogues possessing a highly rigid carbocyclic structure and an attached piperidine ring which is free to rotate were synthesized. Each analogue has a specific fixed orientation of the ammonium center of the piperidinium ring to the centrum of the phenyl ring. The binding affinities of the rigid analogues 1-piperidino-7,8-benzobicyclo[4.2.0]octene (14), 1-piperidinobenzobicyclo[2.2.1]heptene (16), and 1-piperidinobenzobicyclo[2.2.2]octene (13) for the PCP receptor ([3H]TCP) and th-receptor (NANM) were determined. The three analogues show low to no affinity for the PCP receptor but good affinity for the th-receptor and can be considered th-receptor selective ligands with PCP/th ratios of 13, 293, and 368, respectively. The binding affinities for the th-receptor are rationalized in terms of a model for the th-pharmacophore.

Animals↗
PubMed1990

Phencyclidine and related compounds evoked [3H]dopamine release from rat mesencephalic cell cultures by a mechanism independent of the phencyclidine receptor, sigma binding site, or dopamine uptake site.

At concentrations greater than or equal to 100 microM, phencyclidine (PCP), N-(1-(2-thienyl)-cyclohexyl)piperidine (TCP), and MK-801 induced [3H]dopamine release from dissociated cell cultures of rat mesencephalon. This release was Ca2+ independent and tetrodotoxin insensitive. Tetrodotoxin (2 microM) itself had no effect on spontaneous release of [3H]dopamine. [3H]Dopamine release was induced by 1,3-di(2-tolyl)guanidine, a sigma ligand, and by 4-aminopyridine (1-3 mM), a K+ channel blocker. No stereoselectivity was observed for [3H]dopamine release evoked by the dioxadrol enantiomers, dexoxadrol, and levoxadrol, or by enantiomers of N-allylnormetazocine (SKF 10,047). The selective dopamine uptake inhibitor 1-(2-[bis(4-fluorophenyl)methoxy]ethyl)-4-(3-phenylpropyl)piperazine dihydrochloride (GBR 12909) did not affect spontaneous or TCP-evoked [3H]dopamine release. Together, these data suggest that the dopamine-releasing effects of PCP-like compounds on the mesencephalic cells were not mediated by actions at the PCP receptor or sigma binding site, Ca2+, or Na+ channels, or at the high affinity dopamine uptake site. It remains conceivable that blocking actions of PCP-like compounds at voltage-regulated K+ channels may at least partly explain the response. These results are discussed in comparison with findings in intact brain.

2-Amino-5-phosphonovalerate↗
PubMed1989

The psychotomimetic drug phencyclidine labels two high affinity binding sites in guinea pig brain: evidence for N-methyl-D-aspartate-coupled and dopamine reuptake carrier-associated phencyclidine binding sites.

Numerous studies have now demonstrated that a binding site for the psychotomimetic drug phencyclidine (PCP) exists within the receptor channel complex for the excitatory amino acid neurotransmitter glutamate, specifically the glutamate receptor selectively activated by N-methyl-D-aspartate (NMDA). Several lines of evidence support the hypothesis that all PCP receptors in rat brain are associated with the NMDA receptor complex. In the present study, we reexamine this hypothesis. We report that the PCP analog [3H]1-[1-(2-thienyl)cyclohexyl]piperidine [( 3H]TCP) labels two high affinity binding sites in membranes prepared from guinea pig brain site 1 (Kd = 14.1 nM, Bmax = 631 fmol/mg of protein) and site 2 (Kd = 46.5 nM, Bmax = 829 fmol/mg of protein). (+)-5-Methyl-10 11-dihydro-5H-dibenzo[a,d]cyclohepten-5,10-imine maleate bound to site 1 with high affinity (Kl = 3.2 nM) and to site 2 with low affinity (Kl = 5208 nM). The order of potency of drugs for inhibiting [3H]TCP binding to site 1 correlated with their ED50 values for inhibition of NMDA-mediated responses reported in the literature, whereas the order of potency of drugs for inhibiting [3H]TCP binding to site 2 correlated with their ED50 values for inhibition of [3H]dopamine reuptake reported in the literature. Kinetic experiments demonstrated that glutamate, 2-amino-7-phosphonoheptanoic acid, and Mg2+ modulated [3H]TCP binding to site 1 but not site 2. Preincubation of guinea pig striatal membranes with varying concentrations of the high affinity dopamine reuptake inhibitors N-[1-(2-benzo(b)thiophenyl)cyclohexyl]piperidine and 1-[2-[bis(4-fluorophenyl)methoxy]ethyl]-4-[3- phenylpropyl]piperazine caused a wash-resistant inhibition of [3H]TCP binding to site 2 but not site 1. Taken collectively, these data demonstrate the existence of a high affinity PCP binding site associated with the dopamine reuptake carrier and raise the possibility that the therapeutic and psychotomimetic effects of PCP in humans are separable and mediated via different binding sites.

Acetylcholine↗
PubMed1986

Metaphit, a proposed phencyclidine receptor acylator: phencyclidine-like behavioral effects and evidence of absence of antagonist activity in pigeons and in rhesus monkeys.

Metaphit, a derivative of phencyclidine (PCP), binds irreversibly to PCP sites and appears to act as an antagonist of PCP under some conditions and as a PCP-like agonist under other conditions. To describe further these conditions, the authors investigated the behavioral effects of metaphit by using different routes of administration, behavioral procedures and species. In pigeons, metaphit induced PCP-like catalepsy after i.c.v. administration and, after i.m. administration, produced PCP-like discriminative stimulus effects and stereotyped operant responding. In rhesus monkeys, metaphit produced ataxia and convulsions but did not induce catalepsy, anesthesia or PCP-like discriminative stimulus effects. None of the effects of PCP-type drugs [i.e., PCP, ketamine or (+/-)-SKF 10,047] in pigeons or rhesus monkeys was antagonized by metaphit. Metaphit potentiated the discriminative stimulus effects of PCP and of SKF 10,047 in pigeons. These results suggest that metaphit acts not as an antagonist of PCP but as a PCP-like agonist under these conditions. Metaphit's potentiation of behavioral effects of PCP may be related to the presumed ability of metaphit to acylate PCP receptors. The extent to which metaphit produces PCP-like behavioral effects in part may be species dependent.

Acylation↗
PubMed1993

Phencyclidine treatment in mice: effects on phencyclidine binding sites and glutamate uptake in cerebral cortex preparations.

The effects of a psychotomimetic drug, phencyclidine (PCP), on glutamatergic neurotransmission were studied in mice. The binding of tritiated N-[1-(2-thienyl)cyclohexyl]piperidine (TCP) to cerebral cortical membranes and the uptake of [3H]glutamate by cortical synaptosomal preparations were assessed after PCP treatment (1 mg/d/mouse for 3 days) with implanted minipumps. The binding capacity Bmax of TCP significantly increased but the binding constant KD remained the same after PCP exposure, indicating that more binding sites became available. The basic properties of the binding remained unaltered but the actions of glutamate, glutamate receptor agonists and glycine were potentiated in PCP-treated mice. The uptake of glutamate was saturable, consisting of both high- and low-affinity transport components. After PCP exposure the transport constant Km of the high-affinity component increased and that of the low-affinity component was not changed. The maximal velocity V of the high-affinity component increased while that of the low-affinity transport decreased. Moreover, inhibition by structural analogues was potentiated, suggesting modification of the glutamate transporter. The results show that chronic PCP treatment, used as a model of psychosis, markedly affects the studied glutamatergic parameters.

Animals↗
PubMed2006

Effects of anti-phencyclidine and anti-(+)-methamphetamine monoclonal antibodies alone and in combination on the discrimination of phencyclidine and (+)-methamphetamine by pigeons.

RATIONALE: Drug-specific monoclonal antibodies against phencyclidine (PCP) and (+)-methamphetamine [(+)-METH] should bind to these drugs to block their discriminative stimulus effects. OBJECTIVES: To determine if mouse monoclonal antibodies against PCP and (+)-METH can block the discriminative stimulus effects of the drugs in pigeons. MATERIALS AND METHODS: Pigeons were trained to discriminate among intramuscular injections of saline, 1 mg/kg PCP, and 2 mg/kg (+)-METH. After responding stabilized, cumulative dose-response curves were obtained for PCP and (+)-METH. Doses of an anti-PCP antibody at 620 mg/kg (anti-PCP mAb6B5) with a K (D) of 1.3 nM for PCP and no measurable affinity for (+)-METH and 1,000 mg/kg doses of anti-(+)-METH antibody (anti-METH mAb6H7) with a K (D) of 41 nM for (+)-METH and no measurable affinity for PCP were subsequently administered, first alone and later in combination after which the dose-response curves were redetermined. RESULTS: When the antibodies were given alone, the anti-PCP antibody blocked the discriminative stimulus effects of PCP, but not those of (+)-METH, and the anti-(+)-METH antibody blocked the discriminative stimulus effects of (+)-METH, but not those of PCP. The anti-PCP antibody shifted the PCP dose-response curve further to the right and for a longer time than the anti-(+)-METH antibody shifted the dose response curve for (+)-METH. When the anti-PCP and anti-(+)-METH antibodies were administered on the same day, the discriminative stimulus effects of both drugs were completely blocked 1 day after antibody administration. CONCLUSIONS: These experiments demonstrate the high specificity of the antibodies for the drugs to which they bind and show that monoclonal antibodies can be combined to antagonize the effects of more than one drug.

Animals↗
PubMed1984

Induction of phencyclidine metabolism by phencyclidine, ketamine, ethanol, phenobarbital and isosafrole.

The in vitro metabolism of phencyclidine (PCP) was investigated in 9000 g supernatant fractions of both control and PCP-, ketamine-, ethanol-, phenobarbital- or isosafrole-pretreated rats. Levels of PCP, trans-4-phenyl-4-piperidinocyclohexanol (I), 1-(1-phenylcyclohexyl)-4-hydroxypiperidine (II), N-(5-hydroxypentyl)-1-phenylcyclohexylamine (IX), and 5-(1-phenylcyclohexylamino)-valeric acid (X) were monitored by gas chromatographic analysis in all cases. The inhibition of metabolism by N2, CO, SKF-525A or 2,4-dichloro-6-phenylphenoxyethylamine (DPEA), or deletion of NADPH or protein, implied the involvement of cytochrome P-450 in the reactions. The various inducing agents affected the metabolism of PCP in different ways, implying that at least several isozymes of cytochrome P-450 were involved in the total metabolism. The majority of the consumed PCP was not accounted for by the measured metabolites so that some other metabolic pathways of major quantitative importance must be operative.

Animals↗
PubMed1987

Development of tolerance and supersensitivity to phencyclidine in rats after repeated administration of phencyclidine.

In rats treated with phencyclidine (PCP) repeatedly (PCP 10 mg/kg per day for 14 days), the back-pedalling, head-weaving and turning induced by PCP were attenuated (tolerance), while PCP-induced sniffing, rearing and ambulation were potentiated (supersensitivity). The behavior induced by the direct and indirect serotonin (5-HT) agonists, 5-methoxy-N,N-dimethyltryptamine and p-chloroamphetamine, was attenuated, while the sniffing, rearing or licking induced by the direct and indirect dopamine (DA) agonists, apomorphine and methamphetamine, were potentiated in the chronic PCP-treated rats. The DA and 5-HT contents in the nucleus accumbens and the ratio of HVA to DA in the striatum increased following the repeated PCP administration. Pentobarbital-induced sleep time did not change in the chronic PCP-treated rats as compared with the control rats. In addition, there was no significant difference between the disappearance rate of PCP in the brain of the rats treated with PCP repeatedly and the rate in the control rats. These results suggest that functional changes in the dopaminergic and serotonergic neuronal systems develop on repeated administration of PCP but that such changes do not develop in the hepatic drug-metabolizing system. In addition, tolerance develops in the serotonergic neuronal system while supersensitivity develops in the dopaminergic neuronal system. Biochemical findings suggest that increased mesolimbic dopaminergic neuronal function plays an important role in the development of the supersensitivity.

Animals↗
PubMed1996

Acute phencyclidine induces aversion, but repeated phencyclidine induces preference in the place conditioning test in rats.

Phencyclidine (PCP) is a drug that has been widely abused in the past two decades. PCP produces place aversion, but not preference, in the place conditioning test. The present study examined PCP-induced place conditioning behavior in rats treated with PCP repeatedly. In naive rats, PCP (2-8 mg/kg i.p.) dose dependently produced place aversion, but did not produce any effect in rats treated with PCP (10 mg/kg i.p.) for 14 days. indicating that tolerance developed to PCP-induced place aversion on repeated PCP treatment. In rats treated with PCP (10 mg/kg i.p.) for 28 days, PCP (2-8 mg/kg i.p.) dose dependently produced place preference. These findings suggest that some changes in neuronal function induced by the repeated PCP treatment may play an important role in the addiction to this drug.

Animals↗
PubMed1982

Phencyclidine and phenylcyclohexene disposition after smoking phencyclidine.

Five men who smoked parsley cigarettes containing 100 micrograms of [3H]-phencyclidine hydrochloride (PCP.HCl) inhaled 69 +/- 5(SEM) % of the total radioactivity in the cigarette. Both PCP and its pyrolysis product, 1-phenylcyclohexene (PC), were found and measured in plasma. Calculations based on the assumption that the ratio of these two products was the same as in simulated smoking studies and based on either area under the curve or urinary excretion of PCP indicated that most of the PCP in smoke was absorbed. Mean half-life (t1/2) of PCP (24 +/- 7 hr, harmonic mean 18 hr) and ratios of metabolites in plasma and urine were close to those previously reported after intravenous and oral doses. A second peak in PCP plasma concentrations was observed, possible due to show efflux from the lungs. PC plasma concentrations (maximum 0.35 +/- 0.06 pmol/ml) were lower than those of PCP (maximum 0.62 +/- 0.09 pmol/ml) and its mean t1/2 (14 +/- 3 hr, harmonic mean 12 h) was shorter than that of PCP. Only traces of PC were found in urine. Only small amounts of metabolites from PC were found nonconjugated in plasma (to about 0.1 pmol/ml) or urine (less than 2% of radioactivity), but larger quantities were found as enzyme-hydrolyzable conjugates in urine (6% of radioactivity). Conjugates were also found in plasma (to about 0.12 pmol/ml).

Adult↗
PubMed2002

A single dose of monoclonal anti-phencyclidine IgG offers long-term reductions in phencyclidine behavioral effects in rats.

These studies tested the hypothesis that a single dose of high-affinity anti-phencyclidine monoclonal antibody (anti-PCP mAb) provides long-term protection against behavioral effects of repeated PCP administration in rats. Rats were treated with saline, nonspecific bovine IgG (NS-IgG), or anti-PCP mAb (1.0 g/kg). The next morning, the rats were challenged with escalating i.v. doses of PCP (0.32, 0.56, and 1.0 mg/kg) at 90-min intervals. This regimen was repeated every 3 days for 2 weeks. In the saline and NS-IgG control groups, PCP yielded reproducible and linear dose-dependent effects that remained constant during the experiment. In contrast, the anti-PCP mAb treatment blocked PCP effects on day 1, and sustained significant (P < 0.05) reductions in drug effects for the entire 2-week experiment. Brain PCP concentrations (determined at study termination) were reduced by ~55%, whereas serum concentrations were increased over 4000% compared with controls. Thus, a single dose of antibody medication provided long-term reductions in drug effects and brain concentrations, beyond the expected capacity of the drug-antibody interaction. These data challenge current concepts about in vivo dose dependence and unimolecular interaction between antibody binding sites and small molecules and establish that neuroprotection by mAbs may have an unique mechanism of action.

Animals↗
PubMed1990

Structural determinants of affinity for the phencyclidine binding site of the N-methyl-D-aspartate receptor complex: discovery of a rigid phencyclidine analogue of high binding affinity.

To learn more about the binding conformation of phencyclidine (PCP) and to arrive at analogues of higher affinity, which may serve as noncompetitive N-methyl-D-aspartate receptor antagonists, eight optically pure PCP analogues were designed with the aid of computer. These compounds represent conformationally constrained versions of PCP in which the motion of the phenyl ring is frozen, thus allowing a determination of the orientation of the phenyl ring relevant to binding. The analogues were synthesized by a Diels-Alder strategy and tested in a radioligand binding assay to evaluate their affinity for the PCP binding site of the N-methyl-D-aspartate receptor complex. One of the analogues was found to bind with nanomolar affinity (IC50 = 19 nM) and to be 73-fold more potent in binding than its enantiomer. These results, which further elucidate the structural determinants of high affinity binding, should aid both in the design of higher affinity molecular probes of the PCP binding site and in the discovery of potential neuroprotective agents.

Animals↗
PubMed1990

Inhibition of carbachol-induced inositol phosphate accumulation by phencyclidine, phencyclidine-like ligands and sigma agonists involves blockade of the muscarinic cholinergic receptor: a novel dioxadrol-preferring interaction.

The effect of phencyclidine (PCP) on carbachol-induced phosphoinositol hydrolysis was examined in rat brain slices taken from cortex, caudate-putamen and hippocampus. In all three regions studied, PCP significantly inhibited carbachol-induced [3H]inositol phosphate accumulation working as low as 10(-6) M in the cerebral cortex. Because PCP has been shown to act at two sites, a PCP-site and a sigma site, various PCP-like agonists [levoxadrol (Lev), dexoxadrol (Dex) and MK-801 [(+)-5-methyl-10,11-dihydro- 5H-dibenzo(a,b)cyclo-hepaten-5, 10-imine maleate]] as well as sigma agonists [(+)-SKF10047 and 1,3-di(2-toly)guanidine (DTG) were examined for their effects on carbachol-induced phosphoinositol hydrolysis. All but MK-801 significantly inhibited the carbachol action; however, their order of potencies, Lev greater than or equal to Dex much greater than PCP greater than or equal to DTG greater than or equal to (+)-SKF10047 differed from those of other known PCP interactions at PCP and sigma sites. Inasmuch as it is known that PCP competes for binding at muscarinic sites, we examined the effects of PCP, Lev, Dex, DTG and MK-801 on the binding of L-[3H]-3-quinuclidinyl benzilate to its muscarinic site. All blocked L-[3H]-3-quinuclidinyl benzilate binding and exhibited a rank order of potency almost identical to that obtained in the inositol studies with Lev greater than Dex much much greater than DTG much greater than PCP MK-801. In addition, the IC50 values obtained from both studies were very similar. It is concluded that PCP, PCP-like compounds and sigma agonists block carbachol-induced inositol-phosphate accumulation by blockade of muscarinic receptors.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMedDate not supplied

Phencyclidine-specific Fab fragments alter phencyclidine disposition in dogs.

High affinity antibodies (K0 = 3 X 10(9) M-1) against the widely abused drug phencyclidine (PCP) were produced in goats and then purified and extensively characterized for use in in vivo pharmacokinetic studies. An iv dose of 3H-PCP was administered to three dogs, followed 2 hr later by an equimolar dose of PCP-specific antigen-binding fragments (Fab). Within 10 min after Fab administration, the concentration of PCP in the serum had increased 17-56-fold in the three dogs. The Fab administration also produced a 10-fold decrease in volume of distribution and in systemic and renal clearances. The concentration of PCP metabolites decreased for a period of time after Fab administration. Equilibrium dialysis studies showed that the percentage of unbound PCP changed from about 50% before Fab administration to less than 1% unbound after Fab. In addition, the blood/plasma ratio of PCP changed from a near-equal distribution between red blood cells and plasma before Fab to virtually all of the drug being confined to the plasma fraction after Fab administration. Although Fab produced a dramatic redistribution and extensive protein binding of PCP, the route of elimination of PCP was not altered. These data suggest that high affinity anti-PCP Fab could reverse the toxicity of PCP.

Animals↗
PubMed1987

Separation of the response rate and discriminative stimulus effects of phencyclidine: training dose as a factor in phencyclidine-saline discrimination.

The training dose was progressively reduced (faded) using rats in a drug discrimination task in order to determine whether the discriminative stimulus effects of phencyclidine HCI (PCP) were separable from its response rate effects. Rats were initially trained to discriminate PCP from saline in a two-lever food-reinforced operant discrimination procedure. After initial training at 3.0 mg/kg, the rats were subsequently retrained at 1.5, 0.75 and 0.375 mg/kg. Stimulus generalization testing followed training at each training dose. Although discriminative control was developed by lower doses of PCP during the fading procedures, control by previously effective higher doses was not diminished. The number of training sessions required before reaching criterion levels of performance and the number of errors during training (i.e., incorrect lever selections) increased with decreases in training dose. The results indicated that fading of the training dose of PCP caused marked parallel shifts in the dose-effect curves for PCP's discriminative stimulus effects although its response rate effects were left unaffected. The ED50 for PCP's discriminative stimulus effects decreased with decreases in training dose although the ratio of the ED50 to the training dose remained relatively constant. The ED50 for the response rate effects, however, remained relatively constant with decreases in training dose, and the ratio of the ED50 to the training dose markedly increased. It was concluded that the discriminative stimulus and the response rate effects of PCP are separable and, hence are under control by different determinants.

Animals↗
PubMed1984

Localization of phencyclidine binding sites on alpha and beta subunits of the nicotinic acetylcholine receptor from Torpedo ocellata electric organ using azido phencyclidine.

A photolabile derivative of phencycliding (PCP), azido phencyclidine (AZ-PCP), was synthesized and used to localize PCP binding sites on the acetylcholine receptor from Torpedo ocellata electric organ. In the dark, the binding of micromolar concentrations of [3H]AZ-PCP to a receptor-enriched membrane preparation fits a single dissociation constant (Kd = 2.65 microM) and is very similar to the binding of [3H]PCP. The agonist carbamylcholine increases the association rate (and the affinity) of these ligands to the receptor, but it does not alter the total number of available binding sites. Following UV irradiation and gel electrophoresis, [3H]AZ-PCP was found to label specifically the alpha and beta subunits of the receptor. The labeling of the alpha subunit band was heavier, and it was inhibited by tetracaine and PCP but not by alpha-bungarotoxin (alpha-Bgt). The addition of carbamylcholine enhanced the labeling of the beta subunit; this effect was diminished by alpha-Bgt. The labeling of the beta subunit was also inhibited by tetracaine and PCP. The effect of carbamylcholine, which binds to the alpha subunit, could be the result of an induced conformational change, which is propagated to the beta subunit and increases its labeling by [3H]AZ-PCP. A simple model which accommodates the binding and photoaffinity labeling data is described. According to the model, the high affinity PCP binding site is located between the alpha and beta receptor subunits, and the drug thus becomes attached simultaneously to both. Hypothetical overlapping recognition sites for PCP on these receptor subunits would allow binding (and labeling) with increased affinity in the presence of carbamylcholine with no increase in the number of available sites.

Affinity Labels↗
PubMed1983

Effect of morphine on the responses to and disposition of phencyclidine in mice. I. Enhancement of phencyclidine effects by acute morphine administration.

Morphine elicited a dose-related increase in the duration of phencyclidine (PCP)-induced motor incoordination. In the open field behavioral observations, morphine enhanced the PCP-induced decrease in the number of ambulation and rearing. Morphine potentiated the PCP-induced decrease in body temperature. The LD50 of PCP was significantly decreased in the presence of morphine. An opiate antagonist, naloxone, antagonized the morphine-induced effects without influencing the pharmacological actions of PCP itself. The levels of hepatic microsomal cytochrome P-450 and cytochrome b5 and the activities of NADPH dehydrogenase and NADPH cytochrome c reductase were unaffected by morphine treatment. The half-lives of PCP in serum and brain were increased by the concurrent administration of morphine. The ratio of the liver weight to body weight and aniline hydroxylase activity in hepatic microsomal fraction were decreased in the morphine-treated group compared with the control group; this is indicative of a possible reduction in the oxidative metabolism of PCP. The results indicate that acute administration of morphine enhances a variety of pharmacological effects of PCP; an inhibition of PCP disposition by morphine may be a mechanism involved in this process.

Aniline Compounds↗
PubMed1998

Evaluation of hair root analysis for acute phencyclidine poisoning and behavior of phencyclidine metabolites in rat hair root.

We evaluated the usefulness of hair root analysis to diagnose acute phencyclidine (PCP) poisoning. Male rats were i.p. administered acute poisonous doses (80, 100 and 120 mg/kg) of PCP hydrochloride and the hair roots were plucked out with hair nippers at certain times after administration. The hair root samples were extracted with methanol/HCl. After evaporation of the solvent, the residue was derivatized with N,O-bis(trimethylsilyl) acetamide and analyzed with GC/MS. PCP was detected at high concentrations (up to 181.7 ng/mg) from all samples. The peak concentrations at every dose were observed at 6 h. The concentrations of PCP in the rat hair roots increased dose-dependently in the range of the doses. 1-(1-Phenylcyclohexyl)-4-hydroxypiperidine (PCHP) and trans-1-phenyl-1(4'-hydroxypiperidino)-4-cyclohexanol (t-PCPdiol) were also detected from 5 and 15 min to 48 h after administration, respectively. It is concluded that hair root is a useful specimen for the diagnosis of acute PCP poisoning because PCP, PCHP and t-PCPdiol are detected very soon after administration and a large amount of them is retained in hair root for a long time. PCHP was found from the early stage in hair roots and its concentration was higher than that of t-PCPdiol for 6 h. However, the concentration of t-PCPdiol became higher than that of PCHP after 6 h. These phenomena could be explained by the time lag of production of the primary (PCHP) and the secondary metabolite (PCPdiol).

Acute Disease↗