Publications by authors named "Hemby S"

Article Synopsis
  • Oxa-iboga compounds are newly developed analogs of ibogaine, designed to retain therapeutic benefits while eliminating cardiac safety risks.
  • These compounds demonstrate effectiveness in reducing opioid intake and withdrawal symptoms in animal models, outperforming traditional treatments.
  • Oxa-noribogaine specifically acts as a kappa opioid receptor agonist, offering a unique approach to treating substance use disorders with potential for long-lasting effects.
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Pharmacological targeting of the dopamine D receptor (DR)─expressed in brain regions that control cognition, attention, and decision-making─could be useful for several neuropsychiatric disorders including substance use disorders (SUDs). This study focused on the synthesis and evaluation of a novel series of benzothiazole analogues designed to target DR. We identified several compounds with high DR binding affinity ( ≤ 6.

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Post-mortem studies in the prefrontal cortex and hippocampal formation from schizophrenia patients have revealed significant disruptions in the expression molecules associated with cytoarchitecture, synaptic structure, function, and plasticity, known to be regulated in part by brain derived neurotrophic factor (BDNF). Interestingly, several studies using postmortem brain tissue from individuals diagnosed with schizophrenia have revealed a significant reduction in mRNA and protein levels in the dorsolateral prefrontal cortex (DLPFC), hippocampus and related areas; however, differentiating the effects of illness from antipsychotic history has remained difficult. We hypothesized that chronic antipsychotic treatment may contribute to the altered mRNA and protein expression observed in post-mortem brains of individuals diagnosed with schizophrenia.

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Three previously undescribed diketomorpholine natural products, along with the known phenalenones, herqueinone and norherqueinone, were isolated from the mycoparasitic fungal strain G1071, which was identified as a Penicillium sp. in the section Sclerotiora. The structures were established by analyzing NMR data and mass spectrometry fragmentation patterns.

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The safety and efficacy of kratom (Mitragyna speciosa) for treatment of pain is highly controversial. Kratom produces more than 40 structurally related alkaloids, but most studies have focused on just two of these, mitragynine and 7-hydroxymitragynine. Here, we profiled 53 commercial kratom products using untargeted LC-MS metabolomics, revealing two distinct chemotypes that contain different levels of the alkaloid speciofoline.

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Schizophrenia and bipolar disorder are serious mental illnesses that affect more than 2% of adults. While large-scale genetics studies have identified genomic regions associated with disease risk, less is known about the molecular mechanisms by which risk alleles with small effects lead to schizophrenia and bipolar disorder. In order to fill this gap between genetics and disease phenotype, we have undertaken a multi-cohort genomics study of postmortem brains from controls, individuals with schizophrenia and bipolar disorder.

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Multiple lines of evidence point to glutamatergic signaling in the postsynaptic density (PSD) as a pathophysiologic mechanism in schizophrenia. Integral to PSD glutamatergic signaling is reciprocal interplay between GluN and mGluR5 signaling. We examined agonist-induced mGluR5 signaling in the postmortem dorsolateral prefrontal cortex (DLPFC) derived from 17 patients and age-matched and sex-matched controls.

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Kratom, derived from the plant Mitragyna speciosa, is receiving increased attention as an alternative to traditional opiates and as a replacement therapy for opiate dependence. Mitragynine (MG) and 7-hydroxymitragynine (7-HMG) are major psychoactive constituents of kratom. While MG and 7-HMG share behavioral and analgesic properties with morphine, their reinforcing effects have not been examined to date.

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Dopamine D2 receptors (D2Rs) in the ventral tegmental area (VTA) and the nucleus accumbens (NAc) are associated with vulnerability to addiction; however, whether D2Rs in these two brain regions play differential roles in regulation of drug intake is unknown. Here, we compared the effect of decreased mRNA level of Drd2 in each region on cocaine self-administration in a dose-response function. Drd2 mRNA levels in rat VTA or NAc were knocked down by bilateral microinjection of lentivirus coding shRNAs against rat Drd2 or scrambled shRNA.

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Over 100 genetic loci harbor schizophrenia-associated variants, yet how these variants confer liability is uncertain. The CommonMind Consortium sequenced RNA from dorsolateral prefrontal cortex of people with schizophrenia (N = 258) and control subjects (N = 279), creating a resource of gene expression and its genetic regulation. Using this resource, ∼20% of schizophrenia loci have variants that could contribute to altered gene expression and liability.

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Unlabelled: Epidemiological findings suggest that diabetic individuals are at a greater risk for developing Alzheimer's disease (AD). To examine the mechanisms by which diabetes mellitus (DM) may contribute to AD pathology in humans, we examined brain tissue from streptozotocin-treated type 1 diabetic adult male vervet monkeys receiving twice-daily exogenous insulin injections for 8-20 weeks. We found greater inhibitory phosphorylation of insulin receptor substrate 1 in each brain region examined of the diabetic monkeys when compared with controls, consistent with a pattern of brain insulin resistance that is similar to that reported in the human AD brain.

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Increased neuronal densities in subcortical white matter have been reported for some cases with schizophrenia. The underlying cellular and molecular mechanisms remain unresolved. We exposed 26 young adult macaque monkeys for 6 months to either clozapine, haloperidol or placebo and measured by structural MRI frontal gray and white matter volumes before and after treatment, followed by observer-independent, flow-cytometry-based quantification of neuronal and non-neuronal nuclei and molecular fingerprinting of cell-type specific transcripts.

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Cocaine abuse in HIV patients accelerates the progression and severity of neuropathology, motor impairment and cognitive dysfunction compared to non-drug using HIV patients. Cocaine and HIV interact with the dopamine transporter (DAT); however, the effect of their interaction on DAT binding remains understudied. The present study compared the dose-response functions for intravenous self-administration of cocaine and heroin between male HIV-1 transgenic (HIV-1 Tg) and Fischer 344 rats.

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Background: Impaired glutamatergic signaling is believed to underlie auditory cortex pyramidal neuron dendritic spine loss and auditory symptoms in schizophrenia. Many schizophrenia risk loci converge on the synaptic glutamate signaling network. We therefore hypothesized that alterations in glutamate signaling protein expression and co-expression network features are present in schizophrenia.

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Numerous investigations support decreased glutamatergic signaling as a pathogenic mechanism of schizophrenia, yet the molecular underpinnings for such dysregulation are largely unknown. In the post-mortem dorsolateral prefrontal cortex (DLPFC), we found striking decreases in tyrosine phosphorylation of N-methyl-D aspartate (NMDA) receptor subunit 2 (GluN2) that is critical for neuroplasticity. The decreased GluN2 activity in schizophrenia may not be because of downregulation of NMDA receptors as MK-801 binding and NMDA receptor complexes in postsynaptic density (PSD) were in fact increased in schizophrenia cases.

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Background: An estimated 18 million adults in the United States meet the clinical criteria for diagnosis of alcohol abuse or alcoholism, a disorder ranked as the third leading cause of preventable death. In addition to brain pathology, heavy alcohol consumption is comorbid with damage to major organs including heart, lungs, liver, pancreas, and kidneys. Much of what is known about risk for and consequences of heavy consumption derive from rodent or retrospective human studies.

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Concurrent use of cocaine and heroin (speedball) has been shown to exert synergistic effects on dopamine neurotransmission in the nucleus accumbens (NAc), as observed by significant increases in extracellular dopamine levels and compensatory elevations in the maximal reuptake rate of dopamine. The present studies were undertaken to determine whether chronic self-administration of cocaine, heroin or a combination of cocaine:heroin led to compensatory changes in the abundance and/or affinity of high- and low-affinity DAT binding sites. Saturation binding of the cocaine analog [(125) I] 3β-(4-iodophenyl)tropan-2β-carboxylic acid methyl ester ([(125) I]RTI-55) in rat NAc membranes resulted in binding curves that were best fit to two-site binding models, allowing calculation of dissociation constant (Kd ) and binding density (Bmax ) values corresponding to high- and low-affinity DAT binding sites.

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Background: Chronic alcohol consumption reduces brain serotonin and alters the synaptic mechanisms involved in memory formation. Hippocampal 5-HT1A receptors modulate these mechanisms, but the neuroadaptive response of 5HT1A receptors to chronic alcohol self-administration is not well understood.

Methods: Hippocampal tissue from monkeys that voluntarily self-administered ethanol for 12 months (n=9) and accompanying controls (n=8) were prepared for in vitro receptor autoradiography and laser capture microdissection.

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The anterior hippocampus is associated with emotional functioning and hippocampal volume is reduced in depression. We reported reduced neuropil volume and number of glia in the dentate gyrus (DG) and cornu ammonis (CA)1 of the anterior hippocampus in behaviorally depressed adult female cynomolgus macaques. To determine the biochemical correlates of morphometric and behavioral differences between behaviorally depressed and nondepressed adult female monkeys, glial and synaptic transcripts and protein levels were assessed in the DG, CA3 and CA1 of the anterior hippocampus.

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Article Synopsis
  • There has been significant advancement in personalized drug development, especially in cancer treatment, mainly due to the discovery of drug development tools (DDTs) like biomarkers that help tailor therapies to individual patients.
  • Similar advancements for substance use disorders (SUDs) could lead to better diagnostic and treatment options, especially for cocaine dependence, which currently lacks effective biomarkers.
  • The review discusses current challenges and opportunities in identifying and developing these biomarkers for cocaine dependence, emphasizing the need for more research to validate these tools before they can be effectively used in clinical settings.
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Chronic cocaine administration regulates the expression of several proteins related to dopaminergic signaling and synaptic function in the mesocorticolimbic pathway, including the prefrontal cortex. Functional abnormalities in the prefrontal cortex are hypothesized to be due in part to the expression of proteins involved in dopamine signaling and plasticity. Adult male rhesus monkeys self-administered cocaine (i.

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Proteoglycans like syndecan-3 have complex signaling roles in addition to their function as structural components of the extracellular matrix. Here, we show that syndecan-3 in the lateral hypothalamus has an unexpected new role in limiting compulsive cocaine intake. In particular, we observe that syndecan-3 null mice self-administer greater amounts of cocaine than wild-type mice.

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Cocaine/heroin combinations (speedball) exert synergistic neurochemical and behavioral effects that are thought to contribute to the increased abuse potential and subjective effects reported by polydrug users. In vivo fast-scan cyclic voltammetry was used to examine the effects of chronic intravenous self-administration (25 consecutive sessions) of cocaine (250 μg/inf), heroin (4.95 μg/inf) and speedball (250/4.

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Functional impairment of the orbital and medial prefrontal cortex underlies deficits in executive control that characterize addictive disorders, including alcohol addiction. Previous studies indicate that alcohol alters glutamate neurotransmission and one substrate of these effects may be through the reconfiguration of the subunits constituting ionotropic glutamate receptor (iGluR) complexes. Glutamatergic transmission is integral to cortico-cortical and cortico-subcortical communication and alcohol-induced changes in the abundance of the receptor subunits and/or their splice variants may result in critical functional impairments of prefrontal cortex in alcohol dependence.

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Functional genomics and proteomics approaches are being employed to evaluate gene and encoded protein expression changes with the tacit goal to find novel targets for drug discovery. Genome-wide association studies (GWAS) have attempted to identify valid candidate genes through single nucleotide polymorphism (SNP) analysis. Furthermore, microarray analysis of gene expression in brain regions and discrete cell populations has enabled the simultaneous quantitative assessment of relevant genes.

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