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Biological Psychiatry Global Open... Jan 2024Phencyclidine (PCP) causes psychosis, is abused with increasing frequency, and was extensively used in antipsychotic drug discovery. PCP discoordinates hippocampal...
BACKGROUND
Phencyclidine (PCP) causes psychosis, is abused with increasing frequency, and was extensively used in antipsychotic drug discovery. PCP discoordinates hippocampal ensemble action potential discharge and impairs cognitive control in rats, but how this uncompetitive NMDA receptor (NMDAR) antagonist impairs cognition remains unknown.
METHODS
The effects of PCP were investigated on hippocampal CA1 ensemble action potential discharge in vivo in urethane-anesthetized rats and during awake behavior in mice, on synaptic responses in ex vivo mouse hippocampus slices, in mice on a hippocampus-dependent active place avoidance task that requires cognitive control, and on activating the molecular machinery of translation in acute hippocampus slices. Mechanistic causality was assessed by comparing the PCP effects with the effects of inhibitors of protein synthesis, group I metabotropic glutamate receptors (mGluR1/5), and subunit-selective NMDARs.
RESULTS
Consistent with ionotropic actions, PCP discoordinated CA1 ensemble action potential discharge. PCP caused hyperactivity and impaired active place avoidance, despite the rodents having learned the task before PCP administration. Consistent with metabotropic actions, PCP exaggerated protein synthesis-dependent DHPG-induced mGluR1/5-stimulated long-term synaptic depression. Pretreatment with anisomycin or the mGluR1/5 antagonist MPEP, both of which repress translation, prevented PCP-induced discoordination and the cognitive and sensorimotor impairments. PCP as well as the NR2A-containing NMDAR antagonist NVP-AAM077 unbalanced translation that engages the Akt, mTOR (mechanistic target of rapamycin), and 4EBP1 translation machinery and increased protein synthesis, whereas the NR2B-containing antagonist Ro25-6981 did not.
CONCLUSIONS
PCP dysregulates translation, acting through NR2A-containing NMDAR subtypes, recruiting mGluR1/5 signaling pathways, and leading to neural discoordination that is central to the cognitive and sensorimotor impairments.
PubMed: 38298788
DOI: 10.1016/j.bpsgos.2023.04.009 -
JAMA Network Open Mar 2024Young children are ingesting illicit drugs at increased rates, but it is unknown what the associated child protection system (CPS) responses are when a child tests...
IMPORTANCE
Young children are ingesting illicit drugs at increased rates, but it is unknown what the associated child protection system (CPS) responses are when a child tests positive.
OBJECTIVE
To document the child protection system involvement and the characteristics of children who test positive for illicit substances.
DESIGN, SETTING, AND PARTICIPANTS
This retrospective cross-sectional study linked medical discharge and child protection system administrative data. The setting was Rady Children's Hospital San Diego, a free-standing pediatric hospital in California. Participants included all emergency department and inpatient medical encounters involving children aged 12 years or younger with a positive urine drug test between 2016 and 2021. Statistical analysis was performed from February 2023 to January 2024.
EXPOSURE
Drug type, including amphetamines, barbiturates, benzodiazepines, cannabis, cocaine, fentanyl, opiates, and phencyclidine.
MAIN MEASURES AND OUTCOMES
CPS responses associated with the medical encounter including reports, substantiations, case openings, and out-of-home placements.
RESULTS
A total of 511 emergency department and inpatient medical encounters involving children had a positive drug test (262 [51.3%] were female; 309 [60.5%] were age 6 years or younger; fewer than 10 [<3.0%] were American Indian or Alaska Native; 252 [49.3%] were Hispanic [any race], 20 [3.9%] were non-Hispanic Asian, 56 [11.0%] were non-Hispanic Black, 143 [28.0%] were non-Hispanic White, 36 [7.0%] had other or unknown race and ethnicity; 233 [43.6%] had a CPS report prior to the medical encounter). Following the positive screen, 244 (47.7%) were reported to child protection, and 61 (11.9%) were placed out-of-home within 30 days. Mean (SD) quarterly counts of encounters with positive drug tests doubled after the COVID-19 pandemic onset (32.9 [9.8]) compared with prior to the pandemic onset (16.5 [4.7]); for encounters positive for cannabis, mean (SD) quarterly counts were 3 times as high after the pandemic onset than prior (16.6 [4.7] vs 5.7 [2.9]). Encounters for children under age 1 were significantly more likely to have associated child protection reports (relative risk [RR], 2.91 [95% CI, 2.21-3.83]) and child protection case openings (RR, 1.71 [95% CI, 1.07-2.72]) than encounters involving older children.
CONCLUSIONS AND RELEVANCE
In this cross-sectional study of emergency department and inpatient medical encounters, less than half of children with positive urine drug screens were reported to CPS; out-of-home placements were uncommon. With increased encounters for positive drug tests, it is unclear what services these children and families are receiving.
Topics: Child; Humans; Female; Adolescent; Child, Preschool; Male; Cross-Sectional Studies; Pandemics; Retrospective Studies; Urine; Urinalysis; Cannabinoid Receptor Agonists; Cannabis; Hallucinogens
PubMed: 38512254
DOI: 10.1001/jamanetworkopen.2024.3133 -
Journal of Psychopharmacology (Oxford,... Jul 2020Rodent behavioural assays are widely used to delineate the mechanisms of psychiatric disorders and predict the efficacy of drug candidates. Conventional behavioural...
Temporal dissociation of phencyclidine: Induced locomotor and social alterations in rats using an automated homecage monitoring system - implications for the 3Rs and preclinical drug discovery.
BACKGROUND
Rodent behavioural assays are widely used to delineate the mechanisms of psychiatric disorders and predict the efficacy of drug candidates. Conventional behavioural paradigms are restricted to short time windows and involve transferring animals from the homecage to unfamiliar apparatus which induces stress. Additionally, factors including environmental perturbations, handling and the presence of an experimenter can impact behaviour and confound data interpretation. To improve welfare and reproducibility these issues must be resolved. Automated homecage monitoring offers a more ethologically relevant approach with reduced experimenter bias.
AIM
To evaluate the effectiveness of an automated homecage system at detecting locomotor and social alterations induced by phencyclidine (PCP) in group-housed rats. PCP is an N-methyl-D-aspartate (NMDA) receptor antagonist commonly utilised to model aspects of schizophrenia.
METHODS
Rats housed in groups of three were implanted with radio frequency identification (RFID) tags. Each homecage was placed over a RFID reader baseplate for the automated monitoring of the social and locomotor activity of each individual rat. For all rats, we acquired homecage data for 24 h following administration of both saline and PCP (2.5 mg/kg).
RESULTS
PCP resulted in significantly increased distance travelled from 15 to 60 min post injection. Furthermore, PCP significantly enhanced time spent isolated from cage mates and this asociality occured from 60 to 105 min post treatment.
CONCLUSIONS
Unlike conventional assays, in-cage monitoring captures the temporal duration of drug effects on multiple behaviours in the same group of animals. This approach could benefit psychiatric preclinical drug discovery through improved welfare and increased between-laboratory replicability.
Topics: Animals; Behavior, Animal; Disease Models, Animal; Dissociative Disorders; Locomotion; Male; Phencyclidine; Radio Frequency Identification Device; Rats; Reproducibility of Results; Social Behavior; Time Factors
PubMed: 32438848
DOI: 10.1177/0269881120920455 -
Archives of Pathology & Laboratory... Feb 2020Urine drug testing is frequently ordered by health care providers. Immunoassays are widely used for drug testing, yet have potential limitations, including variable...
CONTEXT.—
Urine drug testing is frequently ordered by health care providers. Immunoassays are widely used for drug testing, yet have potential limitations, including variable cross-reactivity. The last decade has seen worsening of a prescription drug abuse epidemic.
OBJECTIVE.—
To use data from a College of American Pathologists proficiency testing survey, Urine Drug Testing, Screening, to determine and summarize the characteristics, performance, and limitations of immunoassays.
DESIGN.—
Seven years of proficiency surveys were reviewed (2011-2017).
RESULTS.—
Rapid growth was seen in participant volumes for specific immunoassays for synthetic opioids (eg, buprenorphine, fentanyl, oxycodone) and 3,4-methylenedioxymethamphetamine ("ecstasy"). Participant volumes remained high for immunoassays targeting less commonly abused drugs such as barbiturates and phencyclidine. For opiate immunoassays, the number of laboratories using a 2000 ng/mL positive cutoff remained stable, and an increasing number adopted a 100 ng/mL cutoff. Opiate and amphetamine immunoassays showed high variability in cross-reactivity for drugs other than the assay calibrator. Assays targeting a single drug or metabolite generally performed well on drug challenges.
CONCLUSIONS.—
Survey results indicate strong clinical interest in urine drug testing and some adoption of new assays. However, urine drug testing availability does not parallel prevailing patterns of drug prescribing and abuse patterns. In particular, specific immunoassays for synthetic opioids and a lower positive cutoff for opiate immunoassays may be underused, whereas immunoassays for barbiturates, methadone, propoxyphene, and phencyclidine may be overused. Laboratories are encouraged to review their test menu, cutoffs, and assay performance and adjust their test offerings based on clinical needs and technical capabilities.
Topics: Analgesics, Opioid; Humans; Immunoassay; Laboratory Proficiency Testing; Retrospective Studies; Substance Abuse Detection
PubMed: 31313960
DOI: 10.5858/arpa.2018-0562-CP -
Scientific Reports Aug 2021High doses of the Cannabis constituent Δ9-tetrahydrocannabinol (THC) increase the risk of psychosis in humans. Highly accessible animal models are needed to address...
High doses of the Cannabis constituent Δ9-tetrahydrocannabinol (THC) increase the risk of psychosis in humans. Highly accessible animal models are needed to address underlying mechanisms. Using zebrafish with a conserved endocannabinoid system, this study investigates the acute effects of THC on adult zebrafish behavior and the mechanisms involved. A concentration-dependent THC-induced behavioral stereotypy akin to THC's effect in rats and the psychotropics phencyclidine and ketamine in zebrafish was established. Distinctive circular swimming during THC-exposure was measured using a novel analytical method that we developed, which detected an elevated Repetition Index (RI) compared to vehicle controls. This was reduced upon co-administration of N-methyl-D-aspartate (NMDA) receptor agonist NMDA, suggesting that THC exerts its effects via biochemical or neurobiological mechanisms associated with NMDA receptor antagonism. Co-treatment of γ-aminobutyric acid receptor antagonist pentylenetetrazol also showed signs of reducing the RI. Since THC-induced repetitive behavior remained in co-administrations with cannabinoid receptor 1 inverse agonist AM251, the phenotype may be cannabinoid receptor 1-independent. Conversely, the inverse cannabinoid receptor 2 agonist AM630 significantly reduced THC-induced behavioral stereotypy, indicating cannabinoid receptor 2 as a possible mediator. A significant reduction of the THC-RI was also observed by the antipsychotic sulpiride. Together, these findings highlight this model's potential for elucidating the mechanistic relationship between Cannabis and psychosis.
Topics: Animals; Behavior, Animal; Disease Models, Animal; Dronabinol; N-Methylaspartate; Piperidines; Psychotic Disorders; Psychotropic Drugs; Pyrazoles; Receptor, Cannabinoid, CB1; Stereotyped Behavior; Zebrafish
PubMed: 34344922
DOI: 10.1038/s41598-021-95016-4 -
Journal of Neuroscience Research Jan 2024Noncompetitive NMDA receptor (NMDAR) antagonists like phencyclidine (PCP) and ketamine cause psychosis-like symptoms in healthy humans, exacerbate schizophrenia symptoms...
Noncompetitive NMDA receptor (NMDAR) antagonists like phencyclidine (PCP) and ketamine cause psychosis-like symptoms in healthy humans, exacerbate schizophrenia symptoms in people with the disorder, and disrupt a range of schizophrenia-relevant behaviors in rodents, including hyperlocomotion. This is negated in mice lacking the GluN2D subunit of the NMDAR, suggesting the GluN2D subunit mediates the hyperlocomotor effects of these drugs. However, the role of GluN2D in mediating other schizophrenia-relevant NMDAR antagonist-induced behavioral disturbances, and in both sexes, is unclear. This study aimed to investigate the role of the GluN2D subunit in mediating schizophrenia-relevant behaviors induced by a range of NMDA receptor antagonists. Using both male and female GluN2D knockout (KO) mice, we examined the effects of the NMDAR antagonist's PCP, the S-ketamine enantiomer (S-ket), and the ketamine metabolite R-norketamine (R-norket) on locomotor activity, anxiety-related behavior, and recognition and short-term spatial memory. GluN2D-KO mice showed a blunted locomotor response to R-norket, S-ket, and PCP, a phenotype present in both sexes. GluN2D-KO mice of both sexes showed an anxious phenotype and S-ket, R-norket, and PCP showed anxiolytic effects that were dependent on sex and genotype. S-ket disrupted spatial recognition memory in females and novel object recognition memory in both sexes, independent of genotype. This datum identifies a role for the GluN2D subunit in sex-specific effects of NMDAR antagonists and on the differential effects of the R- and S-ket enantiomers.
Topics: Animals; Female; Humans; Male; Mice; Ketamine; Phencyclidine; Receptors, N-Methyl-D-Aspartate; Recognition, Psychology
PubMed: 37814998
DOI: 10.1002/jnr.25257 -
Brain Sciences May 2023Schizophrenia is a debilitating psychiatric disorder comprising positive, negative, and cognitive impairments. Most of the animal models developed to understand the... (Review)
Review
Investigating the Robustness of a Rodent "Double Hit" (Post-Weaning Social Isolation and NMDA Receptor Antagonist) Model as an Animal Model for Schizophrenia: A Systematic Review.
Schizophrenia is a debilitating psychiatric disorder comprising positive, negative, and cognitive impairments. Most of the animal models developed to understand the neurobiology and mechanism of schizophrenia do not produce all the symptoms of the disease. Therefore, researchers need to develop new animal models with greater translational reliability, and the ability to produce most if not all symptoms of schizophrenia. This review aimed to evaluate the effectiveness of the rodent "double hit" (post-weaning social isolation and N-methyl-D-aspartate (NMDA) receptor antagonist) model to produce symptoms of schizophrenia. This systematic review was developed according to the 2020 PRISMA guidelines and checklist. The MEDLINE (PubMed) and Ebscohost databases were used to search for studies. The systematic review is based on quantitative animal studies. Studies in languages other than English that could be translated sufficiently using Google translate were also included. Data extraction was performed individually by two independent reviewers and discrepancies between them were resolved by a third reviewer. SYRCLE's risk-of-bias tool was used to test the quality and biases of included studies. Our primary search yielded a total of 47 articles, through different study selection processes. Seventeen articles met the inclusion criteria for this systematic review. Ten of the seventeen studies found that the "double hit" model was more effective in developing various symptoms of schizophrenia. Most studies showed that the "double hit" model is robust and capable of inducing cognitive impairments and positive symptoms of schizophrenia.
PubMed: 37371328
DOI: 10.3390/brainsci13060848 -
European Journal of Pharmacology Aug 20191,2-Diarylethylamines represent a class of molecules that have shown potential in the treatment of pain, epilepsy, neurodegenerative disease and depression. Examples...
1,2-Diarylethylamines represent a class of molecules that have shown potential in the treatment of pain, epilepsy, neurodegenerative disease and depression. Examples include lefetamine, remacemide, and lanicemine. Recently, several 1,2-diarylethylamines including the dissociatives diphenidine, methoxphenidine and ephenidine as well as the opioid MT-45, have appeared as 'research chemicals' or 'legal highs'. Due to their recent emergence little is known about their pharmacology. One of these, 1-[1-(2-fluorophenyl)-2-phenylethyl]pyrrolidine (fluorolintane, 2-F-DPPy), is available for purchase with purported dissociative effects intended to resemble phencyclidine (PCP) and ketamine. To better understand this emerging class, pharmacological investigations were undertaken for the first time on fluorolintane and its five aryl-fluorine-substituted isomers. In vitro binding studies revealed high affinity for N-methyl-D-aspartate (NMDA) receptors with fluorolintane (K = 87.92 nM) with lesser affinities for related compounds. Additional affinities were seen for all compounds at several sites including norepinephrine (NET), serotonin (SERT) and dopamine (DAT) transporters, and sigma receptors. Notably high affinities at DAT were observed, which were in most cases greater than NMDA receptor affinities. Additional functional and behavioral experiments show fluorolintane inhibited NMDA receptor-induced field excitatory postsynaptic potentials in rat hippocampal slices and inhibited long-term potentiation induced by theta-burst stimulation in rat hippocampal slices with potencies consistent with its NMDA receptor antagonism. Finally fluorolintane inhibited prepulse inhibition in rats, a measure of sensorimotor gating, with a median effective dose (ED) of 13.3 mg/kg. These findings are consistent with anecdotal reports of dissociative effects of fluorolintane in humans.
Topics: Animals; Binding Sites; Dose-Response Relationship, Drug; Excitatory Postsynaptic Potentials; Hippocampus; Isomerism; Long-Term Potentiation; Male; Pyrrolidines; Rats; Receptors, N-Methyl-D-Aspartate
PubMed: 31152702
DOI: 10.1016/j.ejphar.2019.172427 -
British Journal of Pharmacology Jul 2020Hispidulin is a flavonoid isolated from Clerodendrum inerme that was found to inhibit intractable motor tics. Previously, we found that hispidulin attenuates...
BACKGROUND AND PURPOSE
Hispidulin is a flavonoid isolated from Clerodendrum inerme that was found to inhibit intractable motor tics. Previously, we found that hispidulin attenuates hyperlocomotion and the disrupted prepulse inhibition induced by methamphetamine and N-methyl-d-aspartate (NMDA) receptor antagonists, two phenotypes of schizophrenia resembling positive symptoms. Hispidulin can inhibit COMT, a dopamine-metabolizing enzyme in the prefrontal cortex (PFC) that is important for social interaction. Here, we investigated whether hispidulin would affect social withdrawal, one of the negative symptoms of schizophrenia.
EXPERIMENTAL APPROACH
We examined whether acute administration of hispidulin would attenuate social withdrawal in two mice models, juvenile isolated disrupted-in-schizophrenia-1 mutant (mutDISC1) mice and chronic phencyclidine (PCP)-treated naïve mice.
KEY RESULTS
In chronic PCP-treated mice, hispidulin (10 mg·kg , i.p.) attenuated social withdrawal similar to that observed with dopamine D receptor antagonist (SCH-23390, 0.02 mg·kg , i.p.) and was mimicked by the selective COMT inhibitor, OR-486 (10 mg·kg , i.p.). Hispidulin increased extracellular dopamine levels in the PFC of chronic PCP-treated mice. In isolated mutDISC1 mice, hispidulin also reversed social withdrawal. In both models, intra-PFC microinjection of a D agonist (SKF-81297: 10 nmol/mouse/bilateral) reversed the impairment of Ser phosphorylation at the GluN1 subunit of NMDA receptors, suggesting the association between GluN1 Ser -phosphorylation and D activation in the PFC exits in both models.
CONCLUSIONS AND IMPLICATIONS
Hispidulin attenuated social withdrawal by activating D receptors indirectly through elevated dopamine levels in the PFC by COMT inhibition. This nature of hispidulin suggests that it a potential novel therapeutic candidate for the treatment of negative symptoms in schizophrenia.
Topics: Animals; Flavones; Mice; Phencyclidine; Prefrontal Cortex; Receptors, N-Methyl-D-Aspartate; Schizophrenia; Social Isolation
PubMed: 32133633
DOI: 10.1111/bph.15043 -
Pharmacological Research Nov 2021Reelin, a large extracellular matrix protein, helps to regulate neuronal plasticity and cognitive function. Several studies have shown that Reelin dysfunction, resulting...
Reelin, a large extracellular matrix protein, helps to regulate neuronal plasticity and cognitive function. Several studies have shown that Reelin dysfunction, resulting from factors such as mutations in gene RELN or low Reelin expression, is associated with schizophrenia (SCZ). We previously reported that microinjection of Reelin into cerebral ventricle prevents phencyclidine-induced cognitive and sensory-motor gating deficits. However, it remains unclear whether and how Reelin ameliorates behavioral abnormalities in the animal model of SCZ. In the present study, we evaluated the effect of recombinant Reelin microinjection into the medial prefrontal cortex (mPFC) on abnormal behaviors induced by MK-801, an N-methyl-D-aspartate receptor antagonist. Microinjection of Reelin into the mPFC prevented impairment of recognition memory of MK-801-treated mice in the novel object recognition test (NORT). On the other hand, the same treatment had no effect on deficits in sensory-motor gating and short-term memory in the pre-pulse inhibition and Y-maze tests, respectively. To establish the neural substrates that respond to Reelin, the number of c-Fos-positive cells in the mPFC was determined. A significant increase in c-Fos-positive cells in the mPFC of MK-801-treated mice was observed when compared with saline-treated mice, and this change was suppressed by microinjection of Reelin into the mPFC. A K2360/2467A Reelin that cannot bind to its receptor failed to ameliorate MK-801-induced cognitive deficits in NORT. These results suggest that Reelin prevents MK-801-induced recognition memory impairment by acting on its receptors to suppress neural activity in the mPFC of mice.
Topics: Animals; Behavior, Animal; Cells, Cultured; Dizocilpine Maleate; Male; Memory Disorders; Mice, Inbred C57BL; Microinjections; Neurons; Neuroprotective Agents; Prefrontal Cortex; Proto-Oncogene Proteins c-fos; Receptors, N-Methyl-D-Aspartate; Recombinant Proteins; Reelin Protein; Mice
PubMed: 34450306
DOI: 10.1016/j.phrs.2021.105832