Opioid receptor expressing neurons of the central amygdala gate behavioral effects of ketamine in mice.

Ketamine has anesthetic, analgesic, and antidepressant properties which may involve multiple neuromodulatory systems. In humans, the opioid receptor (OR) antagonist naltrexone blocks the antidepressant effect of ketamine. It is unclear whether naltrexone blocks a direct effect of ketamine at ORs, or whether normal functioning of the OR system is required to realize the full antidepressant effects of treatment. In mice, the effect of ketamine on locomotion, but not analgesia or the forced swim test, was sensitive to naltrexone and was therefore used as a behavioral readout to localize the effect of naltrexone in the brain. We performed whole-brain imaging of cFos expression in ketamine-treated mice, pretreated with naltrexone or vehicle, and identified the central amygdala (CeA) as the area with greatest difference in cFos intensity. CeA neurons expressing both µOR (MOR) and PKCµ were strongly activated by naltrexone but not ketamine, and selectively interrupting MOR function in the CeA either pharmacologically or genetically blocked the locomotor effects of ketamine. These data suggest that MORs expressed in CeA neurons gate behavioral effects of ketamine but are not direct targets of ketamine.

Maneuvering through Life with Positivity: Estimating the Effects of Foster Youth's Appraisal on Coping Styles.

Youth in foster care tend to experience a disproportional number of adverse life experiences and demonstrate high rates of emotional and behavioral difficulties. According to the transactional model of stress and coping, how youth appraise their experiences influences the type of coping strategies they use in response to adversity, and these relations are key components to understanding later adjustment. However, few studies have examined potential effects of appraisal on coping for youth in foster care. Furthermore, it is not well understood if or how such interaction may vary across age. To address this gap, this study examined potential age moderation of contemporaneous primary, threat-based appraisal effects on coping in a large sample of 490 youth in foster care (48% female, ages 8 to 18) using a series of statistical models which were capable of detecting very general forms of effect moderation. Results indicated that primary appraisal positively predicted direct and prosocial coping, and negatively predicted asocial coping. The linear effects of appraisal on coping did not vary based on age of the youth. The findings suggest that primary appraisals of life events for youth in foster care does have a unique influence on certain coping styles, suggesting perhaps new directions for research on youth exposed to multiple adversities. To promote wider use of the non-parametric time-varying effect model in R, the analysis syntax is also included in the appendix.

The Epidemic-Pandemic Impacts Inventory (EPII): A multisample study examining pandemic-related experiences and their relation to mental health.

The Epidemic-Pandemic Impacts Inventory (EPII) was developed to assess pandemic-related adverse and positive experiences across several key domains, including work/employment, home life, isolation, and quarantine. Several studies have associated EPII-assessed pandemic-related experiences with a wide range of psychosocial factors, most commonly depressive and anxiety symptoms. The present study investigated the degree to which specific types of COVID-19 pandemic-related experiences may be associated with anxiety and depression risk, capitalizing on two large, independent samples with marked differences in sociodemographic characteristics. The present study utilized two adult samples: participants (N = 635) recruited online over a 4-week period in early 2020 (Sample 1) and participants (N = 908) recruited from the student body of a large Northeastern public university (Sample 2). We employed a cross-validated, least absolute shrinkage and selection operator (LASSO) regression approach, as well as a random forest (RF) machine learning algorithm, to investigate classification accuracy of anxiety/depression risk using the pandemic-related experiences from the EPII. The LASSO approach isolated eight items within each sample. Two items from the work/employment and emotional/physical health domains overlapped across samples. The RF approach identified similar items across samples. Both methods yielded acceptable cross-classification accuracy. Applying two analytic approaches on data from two large, sociodemographically unique samples, we identified a subset of sample-specific and nonspecific pandemic-related experiences from the EPII that are most predictive of concurrent depression/anxiety risk. Findings may help to focus on key experiences during future public health disasters that convey greater risk for depression and anxiety symptoms. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

UNRAVELing the synergistic effects of psilocybin and environment on brain-wide immediate early gene expression in mice.

The effects of context on the subjective experience of serotonergic psychedelics have not been fully examined in human neuroimaging studies, partly due to limitations of the imaging environment. Here, we administered saline or psilocybin to mice in their home cage or an enriched environment, immunofluorescently-labeled brain-wide c-Fos, and imaged iDISCO+ cleared tissue with light sheet fluorescence microscopy (LSFM) to examine the impact of environmental context on psilocybin-elicited neural activity at cellular resolution. Voxel-wise analysis of c-Fos-immunofluorescence revealed clusters of neural activity associated with main effects of context and psilocybin-treatment, which were validated with c-Fos+ cell density measurements. Psilocybin increased c-Fos expression in subregions of the neocortex, caudoputamen, central amygdala, and parasubthalamic nucleus while it decreased c-Fos in the hypothalamus, cortical amygdala, striatum, and pallidum in a predominantly context-independent manner. To gauge feasibility of future mechanistic studies on ensembles activated by psilocybin, we confirmed activity- and Cre-dependent genetic labeling in a subset of these neurons using TRAP2+/-;Ai14+ mice. Network analyses treating each psilocybin-sensitive cluster as a node indicated that psilocybin disrupted co-activity between highly correlated regions, reduced brain modularity, and dramatically attenuated intermodular co-activity. Overall, our results indicate that main effects of context and psilocybin were robust, widespread, and reorganized network architecture, whereas context×psilocybin interactions were surprisingly sparse.

UNRAVELing the synergistic effects of psilocybin and environment on brain-wide immediate early gene expression in mice.

The effects of context on the subjective experience of serotonergic psychedelics have not been fully examined in human neuroimaging studies, partly due to limitations of the imaging environment. Here, we administered saline or psilocybin to mice in their home cage or an enriched environment, immunofluorescently-labeled brain-wide c-Fos, and imaged cleared tissue with light sheet microscopy to examine the impact of context on psilocybin-elicited neural activity at cellular resolution. Voxel-wise analysis of c-Fos-immunofluorescence revealed differential neural activity, which we validated with c-Fos + cell density measurements. Psilocybin increased c-Fos expression in the neocortex, caudoputamen, central amygdala, and parasubthalamic nucleus and decreased c-Fos in the hypothalamus, cortical amygdala, striatum, and pallidum. Main effects of context and psilocybin-treatment were robust, widespread, and spatially distinct, whereas interactions were surprisingly sparse.

Adding fuel to the fire? Examining exposure to potentially stressful or traumatic events before and during the COVID-19 pandemic in low-income, Black families.

OBJECTIVE: The COVID-19 pandemic has upended the lives of many individuals. While emerging evidence has begun to document health (e.g., infection) and financial (e.g., job loss) consequences, less is known about the day-to-day experiences of some of the country's most vulnerable populations. The current study sought to address this gap in understanding by examining exposure to potentially stressful or traumatic experiences (PSTEs) and their relation to mental health among predominately low-income, African American/Black individuals. METHOD: Adult caregivers (N = 110) from an ongoing longitudinal research project occurring prior the pandemic completed surveys about their exposure to COVID-19-specific PSTEs during the initial months of the pandemic. Information on participants was combined with pre-COVID-19 PSTE exposure and examined in relation to current mental health functioning (e.g., depression). RESULTS: Findings indicated that participants experienced several different types of COVID-19-specific PSTEs across multiple domains, including home, work, social life, and health and well-being. Results from model testing indicated that COVID-19-specific PSTEs were only associated with worry about COVID-19-specifically. Adulthood PSTEs prior to COVID-19 were also associated with current anxiety symptoms. CONCLUSIONS: Among low-income, African American/Black individuals with a history of exposure to PSTEs, additional PSTEs experienced during the COVID-19 pandemic may not contribute significantly to general mental health functioning above and beyond pre-COVID-19 PSTE exposures. Taken together, research on PSTE exposure from the pandemic should make attempts to account for lifetime PSTE exposure to most accurately evaluate current mental health concerns, especially among marginalized populations. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

"Selective" serotonin 5-HT2A receptor antagonists.

Blockade of the serotonin 5-HT2A G protein-coupled receptor (5-HT2AR) is a fundamental pharmacological characteristic of numerous antipsychotic medications, which are FDA-approved to treat schizophrenia, bipolar disorder, and as adjunctive therapies in major depressive disorder. Meanwhile, activation of the 5-HT2AR by serotonergic psychedelics may be useful in treating neuropsychiatric indications, including major depressive and substance use disorders. Serotonergic psychedelics and other 5-HT2AR agonists, however, often bind other receptors, and standard 5-HT2AR antagonists lack sufficient selectivity to make well-founded mechanistic conclusions about the 5-HT2AR-dependent effects of these compounds and the general neurobiological function of 5-HT2ARs. This review discusses the limitations and strengths of currently available "selective" 5-HT2AR antagonists, the molecular determinants of antagonist selectivity at 5-HT2ARs, and the utility of molecular pharmacology and computational methods in guiding the discovery of novel unambiguously selective 5-HT2AR antagonists.

A new class of 5-HT2A /5-HT2C receptor inverse agonists: Synthesis, molecular modeling, in vitro and in vivo pharmacology of novel 2-aminotetralins.

BACKGROUND AND PURPOSE: The 5-HT receptor subtypes 5-HT2A and 5-HT2C are important neurotherapeutic targets, though, obtaining selectivity over 5-HT2B and H1 receptors is challenging. Here, we delineated molecular determinants of selective binding to 5-HT2A and 5-HT2C receptors for novel 4-phenyl-2-dimethylaminotetralins (4-PATs). EXPERIMENTAL APPROACH: We synthesized 42 novel 4-PATs with halogen or aryl moieties at the C(4)-phenyl meta-position. Affinity, function, molecular modeling and 5-HT2A receptor mutagenesis studies were performed to understand structure-activity relationships at 5-HT2 -type and H1 receptors. Lead 4-PAT-type 5-HT2A /5-HT2C receptor inverse agonists were compared with pimavanserin, a selective 5-HT2A /5-HT2C receptor inverse agonist approved to treat Parkinson's disease-related psychosis, in the mouse head twitch response and locomotor activity assays, models relevant to antipsychotic drug development. KEY RESULTS: Most 4-PAT diastereomers in the (2S,4R)-configuration bound non-selectively to 5-HT2A , 5-HT2C and H1 receptors, with >100-fold selectivity over 5-HT2B receptors, whereas diastereomers in the (2R,4R)-configuration bound preferentially to 5-HT2A over 5-HT2C receptors and had >100-fold selectivity over 5-HT2B and H1 receptors. Results suggest that G2385.42 and V2355.39 in 5-HT2A receptors (conserved in 5-HT2C receptors) are important for high affinity binding, whereas interactions with T1945.42 and W1584.56 determine H1 receptor affinity. The 4-PAT analog (2S,4R)-4-(4'-(dimethylamino)-[1,1'-biphenyl]-3-yl)-N,N-dimethyl-1,2,3,4-tetrahydronaphthalen-2-amine, (2S,4R)-2k, a potent and selective 5-HT2A /5-HT2C receptor inverse agonist, had activity like pimavanserin in the mouse head twitch response assay but was distinct in not suppressing locomotor activity. CONCLUSIONS AND IMPLICATIONS: The novel 4-PAT chemotype can yield selective 5-HT2A /5-HT2C receptor inverse agonists for antipsychotic drug development by optimizing ligand-receptor interactions in transmembrane domain 5. Chirality can be exploited to attain selectivity over H1 receptors, which may circumvent sedative effects.

(S)-5-(2'-Fluorophenyl)-N,N-dimethyl-1,2,3,4-tetrahydronaphthalen-2-amine, a Serotonin Receptor Modulator, Possesses Anticonvulsant, Prosocial, and Anxiolytic-like Properties in an Fmr1 Knockout Mouse Model of Fragile X Syndrome and Autism Spectrum Disorder.

Fragile X syndrome (FXS) is a neurodevelopmental disorder characterized by intellectual disabilities and a plethora of neuropsychiatric symptoms. FXS is the leading monogenic cause of autism spectrum disorder (ASD), which is defined clinically by repetitive and/or restrictive patterns of behavior and social communication deficits. Epilepsy and anxiety are also common in FXS and ASD. Serotonergic neurons directly innervate and modulate the activity of neurobiological circuits altered in both disorders, providing a rationale for investigating serotonin receptors (5-HTRs) as targets for FXS and ASD drug discovery. Previously we unveiled an orally active aminotetralin, (S)-5-(2'-fluorophenyl)-N,N-dimethyl-1,2,3,4-tetrahydronaphthalen-2-amine (FPT), that exhibits partial agonist activity at 5-HT1ARs, 5-HT2CRs, and 5-HT7Rs and that reduces repetitive behaviors and increases social approach behavior in wild-type mice. Here we report that in an Fmr1 knockout mouse model of FXS and ASD, FPT is prophylactic for audiogenic seizures. No FPT-treated mice displayed audiogenic seizures, compared to 73% of vehicle-treated mice. FPT also exhibits anxiolytic-like effects in several assays and increases social interactions in both Fmr1 knockout and wild-type mice. Furthermore, FPT increases c-Fos expression in the basolateral amygdala, which is a preclinical effect produced by anxiolytic medications. Receptor pharmacology assays show that FPT binds competitively and possesses rapid association and dissociation kinetics at 5-HT1ARs and 5-HT7Rs, yet has slow association and rapid dissociation kinetics at 5-HT2CRs. Finally, we reassessed and report FPT's affinity and function at 5-HT1ARs, 5-HT2CRs, and 5-HT7Rs. Collectively, these observations provide mounting support for further development of FPT as a pharmacotherapy for common neuropsychiatric symptoms in FXS and ASD.

Synthesis of novel 5-substituted-2-aminotetralin analogs: 5-HT1A and 5-HT7 G protein-coupled receptor affinity, 3D-QSAR and molecular modeling.

The serotonin 5-HT7 G protein-coupled receptor (GPCR) is a proposed pharmacotherapeutic target for a variety of central and peripheral indications, albeit, there are no approved drugs selective for binding 5-HT7. We previously reported that a lead analog based on the 5-substituted-N,N-disubstituted-1,2,3,4-tetrahydronaphthalen-2-amine (5-substituted-2-aminotetralin, 5-SAT) scaffold binds with high affinity at the 5-HT7 GPCR, and can treat symptoms of autism in mouse models; subsequently, the lead was found to have high affinity at the 5-HT1A GPCR. Herein, we report the synthesis of novel 5-SAT analogs to develop a 3-dimensional quantitative structure-affinity relationship (3D-QSAR) at the human 5-HT7 receptor for comparison with similar studies at the highly homologous 5-HT1A receptor. We report 35 new 5-SAT ligands, some with very high affinity (Ki ≤ 1 nM) and stereoselectivity at 5-HT7 + or 5-HT1A receptors, several with modest selectivity (up to 12-fold) for binding at 5-HT7, and, several ligands with high selectivity (up to 40-fold) at the 5-HT1A receptor. 3D-QSAR results indicate that steric extensions at the C(5)-position improve selectivity for the 5-HT7 over 5-HT1A receptor, while steric and hydrophobic extensions at the chiral C(2)-amino position impart 5-HT1A selectivity. In silico receptor homology modeling studies, supplemented with molecular dynamics simulations and binding free energy calculations, were used to rationalize experimentally-determined receptor selectivity and stereoselective affinity results. The data from these studies indicate that the 5-SAT chemotype, previously shown to be safe and efficacious in rodent paradigms of neurodevelopmental and neuropsychiatric disorders, is amenable to structural modification to optimize affinity at serotonin 5-HT7 vs. 5-HT1A GPCRs, as may be required for successful clinical translation.

Adsorption of copper (II) on mesoporous silica: the effect of nano-scale confinement.

Nano-scale spatial confinement can alter chemistry at mineral-water interfaces. These nano-scale confinement effects can lead to anomalous fate and transport behavior of aqueous metal species. When a fluid resides in a nanoporous environments (pore size under 100 nm), the observed density, surface tension, and dielectric constant diverge from those measured in the bulk. To evaluate the impact of nano-scale confinement on the adsorption of copper (Cu2+), we performed batch adsorption studies using mesoporous silica. Mesoporous silica with the narrow distribution of pore diameters (SBA-15; 8, 6, and 4 nm pore diameters) was chosen since the silanol functional groups are typical to surface environments. Batch adsorption isotherms were fit with adsorption models (Langmuir, Freundlich, and Dubinin-Radushkevich) and adsorption kinetic data were fit to a pseudo-first-order reaction model. We found that with decreasing pore size, the maximum surface area-normalized uptake of Cu2+ increased. The pseudo-first-order kinetic model demonstrates that the adsorption is faster as the pore size decreases from 8 to 4 nm. We attribute these effects to the deviations in fundamental water properties as pore diameter decreases. In particular, these effects are most notable in SBA-15 with a 4-nm pore where the changes in water properties may be responsible for the enhanced Cu mobility, and therefore, faster Cu adsorption kinetics.

Classics in Chemical Neuroscience: Aripiprazole.

Aripiprazole was the first antipsychotic developed to possess agonist properties at dopamine D2 autoreceptors, a groundbreaking strategy that presented a new vista for schizophrenia drug discovery. The dopamine D2 receptor is the crucial target of all extant antipsychotics, and all developed prior to aripiprazole were D2 receptor antagonists. Extensive blockade of these receptors, however, typically produces extrapyramidal (movement) side effects, which plagued first-generation antipsychotics, such as haloperidol. Second-generation antipsychotics, such as clozapine, with unique polypharmacology and D2 receptor binding kinetics, have significantly lower risk of movement side effects but can cause myriad additional ones, such as severe weight gain and metabolic dysfunction. Aripiprazole's polypharmacology, characterized by its unique agonist activity at dopamine D2 and D3 and serotonin 5-HT1A receptors, as well as antagonist activity at serotonin 5-HT2A receptors, translates to successful reduction of positive, negative, and cognitive symptoms of schizophrenia, while also mitigating risk of weight gain and movement side effects. New observations, however, link aripiprazole to compulsive behaviors in a small group of patients, an unusual side effect for antipsychotics. In this review, we discuss the chemical synthesis, pharmacology, pharmacogenomics, drug metabolism, and adverse events of aripiprazole, and we present a current understanding of aripiprazole's neurotherapeutic mechanisms, as well as the history and importance of aripiprazole to neuroscience.

Impact of Social Networking Sites on Children in Military Families.

Youth in military families experience a relatively unique set of stressors that can put them at risk for numerous psychological and behavior problems. Thus, there is a need to identify potential mechanisms by which children can gain resiliency against these stressors. One potential mechanism that has yet to be empirically studied with military youth is social networking sites (SNSs). SNSs have gained significant popularity among society, especially youth. Given the significance of these communication tools in youths' lives, it is important to analyze how SNS use may affect military youth and their ability to cope with common military life stressors. The current review examines the potential positive and negative consequences associated with SNS use in coping with three common stressors of youth in military families: parent deployment, frequent relocation, and having a family member with a psychological or physical disability. By drawing from SNS and military literature, we predict that SNS use can be a positive tool for helping children in military families to cope with stressors. However, certain SNS behaviors can potentially result in more negative outcomes. Recommendations for future research are also discussed.

Morphometric Analysis of Recognized Genes for Autism Spectrum Disorders and Obesity in Relationship to the Distribution of Protein-Coding Genes on Human Chromosomes.

Mammalian chromosomes are comprised of complex chromatin architecture with the specific assembly and configuration of each chromosome influencing gene expression and function in yet undefined ways by varying degrees of heterochromatinization that result in Giemsa (G) negative euchromatic (light) bands and G-positive heterochromatic (dark) bands. We carried out morphometric measurements of high-resolution chromosome ideograms for the first time to characterize the total euchromatic and heterochromatic chromosome band length, distribution and localization of 20,145 known protein-coding genes, 790 recognized autism spectrum disorder (ASD) genes and 365 obesity genes. The individual lengths of G-negative euchromatin and G-positive heterochromatin chromosome bands were measured in millimeters and recorded from scaled and stacked digital images of 850-band high-resolution ideograms supplied by the International Society of Chromosome Nomenclature (ISCN) 2013. Our overall measurements followed established banding patterns based on chromosome size. G-negative euchromatic band regions contained 60% of protein-coding genes while the remaining 40% were distributed across the four heterochromatic dark band sub-types. ASD genes were disproportionately overrepresented in the darker heterochromatic sub-bands, while the obesity gene distribution pattern did not significantly differ from protein-coding genes. Our study supports recent trends implicating genes located in heterochromatin regions playing a role in biological processes including neurodevelopment and function, specifically genes associated with ASD.

High-resolution chromosome ideogram representation of recognized genes for bipolar disorder.

Bipolar disorder (BPD) is genetically heterogeneous with a growing list of BPD associated genes reported in recent years resulting from increased genetic testing using advanced genetic technology, expanded genomic databases, and better awareness of the disorder. We compiled a master list of recognized susceptibility and genes associated with BPD identified from peer-reviewed medical literature sources using PubMed and by searching online databases, such as OMIM. Searched keywords were related to bipolar disorder and genetics. Our compiled list consisted of 290 genes with gene names arranged in alphabetical order in tabular form with source documents and their chromosome location and gene symbols plotted on high-resolution human chromosome ideograms. The identified genes impacted a broad range of biological pathways and processes including cellular signaling pathways particularly cAMP and calcium (e.g., CACNA1C, CAMK2A, CAMK2D, ADCY1, ADCY2); glutamatergic (e.g., GRIK1, GRM3, GRM7), dopaminergic (e.g., DRD2, DRD4, COMT, MAOA) and serotonergic (e.g., HTR1A, HTR2A, HTR3B) neurotransmission; molecular transporters (e.g., SLC39A3, SLC6A3, SLC8A1); and neuronal growth (e.g., BDNF, IGFBP1, NRG1, NRG3). The increasing prevalence of BPD calls for better understanding of the genetic etiology of this disorder and associations between the observed BPD phenotype and genes. Visual representation of genes for bipolar disorder becomes a tool enabling clinical and laboratory geneticists, genetic counselors, and other health care providers and researchers easy access to the location and distribution of currently recognized BPD associated genes. Our study may also help inform diagnosis and advance treatment developments for those affected with this disorder and improve genetic counseling for families.

Currently recognized genes for schizophrenia: High-resolution chromosome ideogram representation.

A large body of genetic data from schizophrenia-related research has identified an assortment of genes and disturbed pathways supporting involvement of complex genetic components for schizophrenia spectrum and other psychotic disorders. Advances in genetic technology and expanding studies with searchable genomic databases have led to multiple published reports, allowing us to compile a master list of known, clinically relevant, or susceptibility genes contributing to schizophrenia. We searched key words related to schizophrenia and genetics from peer-reviewed medical literature sources, authoritative public access psychiatric websites and genomic databases dedicated to gene discovery and characterization of schizophrenia. Our list of 560 genes were arranged in alphabetical order in tabular form with gene symbols placed on high-resolution human chromosome ideograms. Genome wide pathway analysis using GeneAnalytics was carried out on the resulting list of genes to assess the underlying genetic architecture for schizophrenia. Recognized genes of clinical relevance, susceptibility or causation impact a broad range of biological pathways and mechanisms including ion channels (e.g., CACNA1B, CACNA1C, CACNA1H), metabolism (e.g., CYP1A2, CYP2C19, CYP2D6), multiple targets of neurotransmitter pathways impacting dopamine, GABA, glutamate, and serotonin function, brain development (e.g., NRG1, RELN), signaling peptides (e.g., PIK3CA, PIK4CA) and immune function (e.g., HLA-DRB1, HLA-DQA1) and interleukins (e.g., IL1A, IL10, IL6). This summary will enable clinical and laboratory geneticists, genetic counselors, and other clinicians to access convenient pictorial images of the distribution and location of contributing genes to inform diagnosis and gene-based treatment as well as provide risk estimates for genetic counseling of families with affected relatives.

Effects of mental resource availability on looming task performance.

Past research has shown that the looming bias-the tendency to judge one's distance to an approaching object as shorter than in actuality-is stronger among people who are physically weak or vulnerable. The current study examined whether the looming bias would also be stronger among people who are mentally weak or vulnerable. We tested that hypothesis by subjecting 46 young adults to cognitive load and examining their perceptions of approaching objects distance. Participants completed two blocks of the looming task, once under high cognitive load (memorizing a seven-digit number) and once under low load (memorizing a two-digit number). Participants exhibited a stronger looming bias under high load than under low load. These findings support the hypothesis that the looming bias will be stronger when people are weak or vulnerable-either physically or mentally-and in need of a larger margin-of-safety.

Quantitative evaluation of MRI and histological characteristics of the 5xFAD Alzheimer mouse brain.

Assessment of ß-amyloid (Aß) plaque load in Alzheimer's disease by MRI would provide an important biomarker to monitor disease progression or treatment response. Alterations in tissue structure caused by the presence of Aß may cause localised changes that can be detected by quantitative T1 and T2 relaxation time measurements averaged over larger areas of tissue than that of individual plaques. We constructed depth profiles of the T1 and T2 relaxation times of the cerebral cortex with subjacent white matter and hippocampus in six 5xFAD transgenic and six control mice at 11 months of age. We registered these profiles with corresponding profiles of three immunohistochemical markers: ß-amyloid; neuron-specific nuclear protein (NeuN), a marker of neuronal cell load; and myelin basic protein (MBP), a marker of myelin load. We found lower T1 in the 5xFAD transgenic mice compared to wild type control mice at all depths, with maximum sensitivity for detection at specific layers. T1 negatively correlated with Aß staining intensity in the 5xFAD mice which had no changes in NeuN and MBP staining compared to wild type mice. We postulate that these relaxation time changes are due to the presence of ß-amyloid in the transgenic mice. It may be clinically feasible to develop a similar layered analysis protocol as a biomarker for Alzheimer's disease in humans.

The protective effects of the nutraceutical, colostrinin, against Alzheimer's disease, is mediated via prevention of apoptosis in human neurones induced by aggregated beta-amyloid.

OBJECTIVE: It has previously been demonstrated that oral administration of ovine Colostrinin (CLN), a proline-rich polypeptide isolated from ovine colostrum, can effectively treat Alzheimer's disease patients. This study aims to determine whether CLN has effects on the aggregation and toxicity of synthetic beta-amyloid (Abeta), implicated as a causative agent of AD. DESIGN AND MEASUREMENTS: Using cell assays, we examined if pre-treatment of neuronal cells with CLN confers protection. RESULTS: The data from cytotoxicity assays (using MTT and LDH) demonstrated that pre-treatment of human neuronal SHSY-5Y cells with 5 microg/ml CLN, for 24 hours, confers neuroprotection against Abeta-induced neurotoxicity. Twenty-four hour pre-treatment with 5 microg/ml CLN was also shown to reduce Abeta 1-40-induced apoptosis in human neuronal cells as determined via qualitative and quantitative apoptosis assays. CONCLUSION: The neuroprotection conferred with CLN pre-treatment was reduced with the Fas ligand (FasL) binding antibody Nok1, suggesting that the effects of CLN may involve a Fas:soluble FasL interaction. These findings indicate that CLN could possibly play a role in the prevention of AD pathogenesis, though the inhibition of Fas-mediated apoptosis.

Molecular interactions of the plasma membrane calcium ATPase 2 at pre- and post-synaptic sites in rat cerebellum.

The plasma membrane calcium extrusion mechanism, PMCA (plasma membrane calcium ATPase) isoform 2 is richly expressed in the brain and particularly the cerebellum. Whilst PMCA2 is known to interact with a variety of proteins to participate in important signalling events [Strehler EE, Filoteo AG, Penniston JT, Caride AJ (2007) Plasma-membrane Ca(2+) pumps: structural diversity as the basis for functional versatility. Biochem Soc Trans 35 (Pt 5):919-922], its molecular interactions in brain synapse tissue are not well understood. An initial proteomics screen and a biochemical fractionation approach identified PMCA2 and potential partners at both pre- and post-synaptic sites in synapse-enriched brain tissue from rat. Reciprocal immunoprecipitation and GST pull-down approaches confirmed that PMCA2 interacts with the post-synaptic proteins PSD95 and the NMDA glutamate receptor subunits NR1 and NR2a, via its C-terminal PDZ (PSD95/Dlg/ZO-1) binding domain. Since PSD95 is a well-known partner for the NMDA receptor this raises the exciting possibility that all three interactions occur within the same post-synaptic signalling complex. At the pre-synapse, where PMCA2 was present in the pre-synapse web, reciprocal immunoprecipitation and GST pull-down approaches identified the pre-synaptic membrane protein syntaxin-1A, a member of the SNARE complex, as a potential partner for PMCA2. Both PSD95-PMCA2 and syntaxin-1A-PMCA2 interactions were also detected in the molecular and granule cell layers of rat cerebellar sagittal slices by immunohistochemistry. These specific molecular interactions at cerebellar synapses may allow PMCA2 to closely control local calcium dynamics as part of pre- and post-synaptic signalling complexes.