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296 result(s) for "Waddington, John"
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Psychosis in Parkinson’s disease and parkinsonism in antipsychotic-naive schizophrenia spectrum psychosis: clinical, nosological and pathobiological challenges
Following the formulation of operational criteria for the diagnosis of psychosis in Parkinson’s disease, a neurodegenerative disorder, the past decade has seen increasing interest in such nonmotor psychopathology that appears to be independent of dopaminergic therapy. Similarly, there has been a resurgence of interest in motor aspects of the neurodevelopmental disorder of schizophrenia, including spontaneous parkinsonism that appears to be independent of antipsychotic treatment. This review first addresses the clinical and nosological challenges of these superficially paradoxical insights and then considers pathobiological challenges. It proposes that diverse modes of disturbance to one or more element(s) in a cortical-striatal-thalamocortical neuronal network, whether neurodegenerative or neurodevelopmental, can result in movement disorder, psychosis or both. It then proposes that time- and site-dependent dysfunction in such a neuronal network may be a generic substrate for the emergence of psychosis not only in Parkinson’s disease and schizophrenia-spectrum disorders but also in other neuropsychiatric disorders in which psychosis, and sometimes movement disorders, can be encountered; these include substance abuse, cerebrovascular disease, cerebral trauma, cerebral neoplasia, epilepsy, Huntington’s disease, frontotemporal dementia, Alzheimer’s disease and multiple sclerosis.
Motor dysfunction, social context and early prodromal features of psychosis: historical acumen, developmental pathobiology and early intervention
[...]motor dysfunction constitutes a more objective, observable index that is amenable to both lay and automated detection. [...]motor dysfunction illustrates an under-appreciated, circular epistemological journey: from a historical literature that clearly indicated motor abnormalities to be intrinsic to psychotic illness, through subsequent decades during which these same motor abnormalities were equated primarily with adverse effects of essentially ubiquitous treatment with antipsychotic drugs, to renaissance of recognition that such motor abnormalities are intrinsic to psychotic illness5, 6, 7–8. [...]after this period motor abnormalities in psychotic illness across its long-term course post-FEP has remained essentially inaccessible: the contemporary imperative to initiate treatment with antipsychotic drugs as early as possible following FEP has necessitated recourse to the historical record to resolve the natural history of movement disorder over the long-term course of untreated psychosis5, 6, 7–8. [...]it is notable that the only contemporary study to have systematically addressed this issue has received so little attention. Using typical assessment instruments, these subjects showed prominent involuntary movements that differed little in either quality or quantity from a parallel control group of otherwise similar subjects who had received conventional long-term treatment with antipsychotic drugs across decades24; furthermore, involuntary movements in the subjects with schizophrenia who had remained antipsychotic-naïve across decades appeared considerably more severe than the typically mild involuntary movements evident in schizophrenia at FEP6,24.
Lipopolysaccharides derived from Porphyromonas gingivalis and Escherichia coli: Differential and interactive effects on novelty-induced hyperlocomotion, blood cytokine levels and TLR4-related processes
Lipopolysaccharide (LPS), a component of the Gram-negative bacterial cell wall, activates Toll-like receptors (TLRs). Porphyromonas gingivalis ( Pg ) may be involved in the progression of periodontal disease. Mice exposed to a novel environment show hyperlocomotion that is inhibited by systemic administration of LPS derived from Escherichia coli ( Ec -LPS). However, whether Pg -LPS influences novelty-induced locomotion is unknown. Accordingly, we carried out an open field test to analyse the effects of Pg -LPS. For comparison, effects of Ec -LPS were also studied. We additionally investigated the influence of systemic administration of Pg -LPS or Ec -LPS on IL-6, TNF-alpha, and IL-10 levels in blood, as they could be involved in the changes in locomotion. The TLR4 receptor antagonist TAK-242 was used to study the involvement of TLR4. Since Pg -LPS may block TLR4 in vitro , we analysed the effects of Pg -LPS on Ec -LPS-induced changes in behavioural and biochemical parameters. Male ddY mice were used. Pg - or Ec -LPS and TAK-242 were administered intraperitoneally. Ec -LPS (840 μg/kg), but not Pg -LPS (100, 500 and 840 μg/kg), inhibited novelty-induced locomotion, which was antagonized by TAK-242 (3.0 mg/kg). Ec -LPS (840 μg/kg) increased blood levels of IL-6 and IL-10, which were antagonized by TAK-242 (3.0 mg/kg). However, TAK-242 did not inhibit Ec -LPS-induced increases in TNF-alpha levels in blood. Pg -LPS (100, 500, and 840 μg/kg) did not alter blood IL-6, TNF-alpha, or IL-10 levels. The Ec -LPS-induced increase in blood IL-10, but not IL-6 and TNF-alpha, levels was inhibited by Pg -LPS (500 μg/kg). These results suggest that TLR4 stimulation mediates the inhibition of novel environment-induced locomotion in mice following systemic administration of Ec -LPS, while also increasing blood IL-6 and IL-10 levels. In contrast, Pg -LPS did not exhibit these effects. The present study also provides in vivo evidence that Pg -LPS can inhibit TLR4-mediated increases in blood levels of IL-10, a cytokine thought to prevent the development of periodontal disease.
Allosteric Modulation of the Sigma-1 Receptor Elicits Antipsychotic-like Effects
Abstract Allosteric modulation represents an important approach in drug discovery because of its advantages in safety and selectivity. SOMCL-668 is the first selective and potent sigma-1 receptor allosteric modulator, discovered in our laboratory. The present work investigates the potential therapeutic effects of SOMCL-668 on phencyclidine (PCP)-induced schizophrenia-related behavior in mice and further elucidates underlying mechanisms for its antipsychotic-like effects. SOMCL-668 not only attenuated acute PCP-induced hyperactivity and PPI disruption, but also ameliorated social deficits and cognitive impairment induced by chronic PCP treatment. Pretreatment with the selective sigma-1 receptor antagonist BD1047 blocked the effects of SOMCL-668, indicating sigma-1 receptor-mediated responses. This was confirmed using sigma-1 receptor knockout mice, in which SOMCL-668 failed to ameliorate PPI disruption and hyperactivity induced by acute PCP and social deficits and cognitive impairment induced by chronic PCP treatment. Additionally, in vitro SOMCL-668 exerted positive modulation of sigma-1 receptor agonist-induced intrinsic plasticity in brain slices recorded by patch-clamp. Furthermore, in vivo lower dose of SOMCL-668 exerted positive modulation of improvement in social deficits and cognitive impairment induced by the selective sigma-1 agonist PRE084. Also, SOMCL-668 reversed chronic PCP-induced down-regulation in expression of frontal cortical p-AKT/AKT, p-CREB/CREB and BDNF in wide-type but not sigma-1 knockout mice. Moreover, administration of the PI3K/AKT inhibitor LY294002 abolished amelioration by SOMCL-668 of chronic PCP-induced schizophrenia-related behaviors by inhibition of BDNF expression. The present data provide initial, proof-of-concept evidence that allosteric modulation of the sigma-1 receptor may be a novel approach for the treatment of psychotic illness.
Keratinocyte-Derived Cytokine in the Hippocampus Disrupts Extinction of Conditioned Fear Memory in Tumor-Bearing Mice
While patients with cancer show a higher prevalence of psychiatric disorders than the general population, the mechanism underlying this interaction remains unclear. The present study examined whether tumor-bearing (TB) mice show psychological changes using the conditioned fear paradigm and the role of cytokines in these changes. TB mice were established by transplantation with mouse osteosarcoma AXT cells. These TB mice were then found to exhibit disruption in extinction of conditioned fear memory. Eighteen cytokines in serum were increased in TB mice, among which i.c.v. injection of interleukin (IL)-1β and IL-6 strengthened fear memory in normal mice. Contents of IL-17 and keratinocyte-derived cytokine (KC) in the amygdala and KC in the hippocampus were increased in TB mice. KC mRNA in both the amygdala and hippocampus was also increased in TB mice, and i.c.v. injection of KC dose-dependently strengthened fear memory in normal mice. In addition, injection of IL-1β, but not IL-6, increased KC mRNA in the amygdala and hippocampus. In TB mice KC mRNA was increased in both astrocytes and microglia of the amygdala and hippocampus. The microglia inhibitor minocycline, but not the astrocyte inhibitor fluorocitrate, alleviated disruption in extinction of conditioned fear memory in TB mice. Microinjection of KC into the hippocampus, but not into the amygdala, increased fear memory in normal mice. These findings indicate that TB mice show an increase in serum cytokines, including IL-1β, that increases KC production in microglia of the hippocampus, which then disrupts extinction of fear memory.
Dihydromyricetin exerts a rapid antidepressant-like effect in association with enhancement of BDNF expression and inhibition of neuroinflammation
Rationale Major depressive disorder (MDD) is a highly prevalent illness that affects large populations across the world, and increasing evidence suggests that neuroinflammation and levels of brain-derived neurotrophic factor (BDNF) are closely related to depression. Dihydromyricetin (DHM) is a kind of flavonoid natural product that has been reported to display multiple pharmacological effects, including anti-inflammatory and anti-oxidative properties, and these may contribute to ameliorate MDD. Objective This study investigated the effect of DHM on depression-related phenotypes in various experimental animal models. Methods The antidepressant-like effect of DHM was validated via depression-related behavioral tests in naïve male C57BL/6 mice, as well as in the acute lipopolysaccharide-induced mouse model of depression. The chronic unpredicted mild stress (CUMS) mouse model of depression was also used to assess the rapid antidepressant-like effect of DHM by tail suspension test (TST), forced swimming test (FST), locomotor activity, and sucrose preference test (SPT). The expression of BDNF and inflammatory factors were determined through Western blotting and enzyme-linked immunosorbent assay, respectively. Results DHM reduced immobility time in the TST and FST both in mice and the acute LPS-induced mouse model of depression. Seven days of DHM treatment ameliorated depression-related behaviors induced by CUMS, whereas similar treatment with the typical antidepressant venlafaxine did not. DHM activated the ERK1/2-CREB pathway and increased glycogen synthase kinase-3 beta (GSK-3β) phosphorylation at ser-9, with upregulation of BDNF expression, in both hippocampal tissues and cultured hippocampal cells. Conclusion The present data indicate that DHM exerts a more rapid antidepressant-like effect than does a typical antidepressant, in association with enhancement of BDNF expression and inhibition of neuroinflammation.
‘Whole-Body’ Perspectives of Schizophrenia and Related Psychotic Illness: miRNA-143 as an Exemplary Molecule Implicated across Multi-System Dysfunctions
A wide array of biological abnormalities in psychotic illness appear to reflect non-cerebral involvement. This review first outlines the evidence for such a whole-body concept of schizophrenia pathobiology, focusing particularly on cardiovascular disease, metabolic syndrome and diabetes, immunity and inflammation, cancer, and the gut–brain axis. It then considers the roles of miRNAs in general and of miRNA-143 in particular as they relate to the epidemiology, pathobiology, and treatment of schizophrenia. This is followed by notable evidence that miRNA-143 is also implicated in each of these domains of cardiovascular disease, metabolic syndrome and diabetes, immunity and inflammation, cancer, and the gut–brain axis. Thus, miRNA-143 is an exemplar of what may be a class of molecules that play a role across the multiple domains of bodily dysfunction that appear to characterize a whole-body perspective of illness in schizophrenia. Importantly, the existence of such an exemplary molecule across these multiple domains implies a coordinated rather than stochastic basis. One candidate process would be a pleiotropic effect of genetic risk for schizophrenia across the whole body.
Silencing microRNA-134 produces neuroprotective and prolonged seizure-suppressive effects
Temporal lobe epilepsy (TLE) is linked to neuron death in the hippocampus. Now David Henshall and colleagues show that miR-134 is upregulated in humans with TLE and in an experimental epilepsy model in mice. Decreasing miR-134 before induction of epilepsy in mice reduces neuron death and the generation of spontaneous seizures. Temporal lobe epilepsy is a common, chronic neurological disorder characterized by recurrent spontaneous seizures. MicroRNAs (miRNAs) are small, noncoding RNAs that regulate post-transcriptional expression of protein-coding mRNAs, which may have key roles in the pathogenesis of neurological disorders. In experimental models of prolonged, injurious seizures (status epilepticus) and in human epilepsy, we found upregulation of miR-134, a brain-specific, activity-regulated miRNA that has been implicated in the control of dendritic spine morphology. Silencing of miR-134 expression in vivo using antagomirs reduced hippocampal CA3 pyramidal neuron dendrite spine density by 21% and rendered mice refractory to seizures and hippocampal injury caused by status epilepticus. Depletion of miR-134 after status epilepticus in mice reduced the later occurrence of spontaneous seizures by over 90% and mitigated the attendant pathological features of temporal lobe epilepsy. Thus, silencing miR-134 exerts prolonged seizure-suppressant and neuroprotective actions; determining whether these are anticonvulsant effects or are truly antiepileptogenic effects requires additional experimentation.