Cysteamine Attenuates the Decreases in TrkB Protein Levels and the Anxiety/Depression-Like Behaviors in Mice Induced by Corticosterone Treatment

OBJECTIVE: Stress and glucocorticoid hormones, which are released into the circulation following stressful experiences, have been shown to contribute significantly to the manifestation of anxiety-like behaviors observed in many neuropsychiatric disorders. Brain-derived neurotrophic factor (BDNF) signaling through its receptor TrkB plays an important role in stress-mediated changes in structural as well as functional neuroplasticity. Studies designed to elucidate the mechanisms whereby TrkB signaling is regulated in chronic stress might provide valuable information for the development of new therapeutic strategies for several stress-related psychiatric disorders. MATERIALS AND METHODS: We examined the potential of cysteamine, a neuroprotective compound to attenuate anxiety and depression like behaviors in a mouse model of anxiety/depression induced by chronic corticosterone exposure. RESULTS: Cysteamine administration (150 mg/kg/day, through drinking water) for 21 days significantly ameliorated chronic corticosterone-induced decreases in TrkB protein levels in frontal cortex and hippocampus. Furthermore, cysteamine treatment reversed the anxiety and depression like behavioral abnormalities induced by chronic corticosterone treatment. Finally, mice deficient in TrkB, showed a reduced response to cysteamine in behavioral tests, suggesting that TrkB signaling plays an important role in the antidepressant effects of cysteamine. CONCLUSIONS: The animal studies described here highlight the potential use of cysteamine as a novel therapeutic strategy for glucocorticoid-related symptoms of psychiatric disorders

Non-Motor and Motor Features in LRRK2 Transgenic Mice

10.1371/journal.pone.0070249PLoS ONE87-POLN

Long-Term Continuous Corticosterone Treatment Decreases VEGF Receptor-2 Expression in Frontal Cortex

Objective: Stress and increased glucocorticoid levels are associated with many neuropsychiatric disorders including schizophrenia and depression. Recently, the role of vascular endothelial factor receptor-2 (VEGFR2/Flk1) signaling has been implicated in stress-mediated neuroplasticity. However, the mechanism of regulation of VEGF/Flk1 signaling under longterm continuous glucocorticoid exposure has not been elucidated. Material and Methods: We examined the possible effects of long-term continuous glucocorticoid exposure on VEGF/Flk1 signaling in cultured cortical neurons in vitro, mouse frontal cortex in vivo, and in post mortem human prefrontal cortex of both control and schizophrenia subjects. Results: We found that long-term continuous exposure to corticosterone (CORT, a natural glucocorticoid) reduced Flk1 protein levels both in vitro and in vivo. CORT treatment resulted in alterations in signaling molecules downstream to Flk1 such as PTEN, Akt and mTOR. We demonstrated that CORT-induced changes in Flk1 levels are mediated through glucocorticoid receptor (GR) and calcium. A significant reduction in Flk1-GR interaction was observed following CORT exposure. Interestingly, VEGF levels were increased in cortex, but decreased in serum following CORT treatment. Moreover, significant reductions in Flk1 and GR protein levels were found in postmortem prefrontal cortex samples from schizophrenia subjects. Conclusions: The alterations in VEGF/Flk1 signaling following long-term continuous CORT exposure represents a molecula

Schizophrenia: do all roads lead to dopamine or is this where they start? Evidence from two epidemiologically informed developmental rodent models

The idea that there is some sort of abnormality in dopamine (DA) signalling is one of the more enduring hypotheses in schizophrenia research. Opinion leaders have published recent perspectives on the aetiology of this disorder with provocative titles such as ‘Risk factors for schizophrenia—all roads lead to dopamine' or ‘The dopamine hypothesis of schizophrenia—the final common pathway'. Perhaps, the other most enduring idea about schizophrenia is that it is a neurodevelopmental disorder. Those of us that model schizophrenia developmental risk-factor epidemiology in animals in an attempt to understand how this may translate to abnormal brain function have consistently shown that as adults these animals display behavioural, cognitive and pharmacological abnormalities consistent with aberrant DA signalling. The burning question remains how can in utero exposure to specific (environmental) insults induce persistent abnormalities in DA signalling in the adult? In this review, we summarize convergent evidence from two well-described developmental animal models, namely maternal immune activation and developmental vitamin D deficiency that begin to address this question. The adult offspring resulting from these two models consistently reveal locomotor abnormalities in response to DA-releasing or -blocking drugs. Additionally, as adults these animals have DA-related attentional and/or sensorimotor gating deficits. These findings are consistent with many other developmental animal models. However, the authors of this perspective have recently refocused their attention on very early aspects of DA ontogeny and describe reductions in genes that induce or specify dopaminergic phenotype in the embryonic brain and early changes in DA turnover suggesting that the origins of these behavioural abnormalities in adults may be traced to early alterations in DA ontogeny. Whether the convergent findings from these two models can be extended to other developmental animal models for this disease is at present unknown as such early brain alterations are rarely examined. Although it is premature to conclude that such mechanisms could be operating in other developmental animal models for schizophrenia, our convergent data have led us to propose that rather than all roads leading to DA, perhaps, this may be where they start

Safety findings from CENTURION, a phase 3 consistency study of lasmiditan for the acute treatment of migraine

Background: Lasmiditan (LTN) is a selective 5-HT1F receptor agonist for the acute treatment of migraine in adults. We present detailed safety findings from the placebo-controlled, double-blind Phase 3 study, of LTN treatment across 4 attacks (CENTURION). Methods: Patients were randomized 1:1:1 to LTN 200 mg (LTN200), LTN100, or a control group that received placebo for 3 attacks and LTN50 for either the 3rd or 4th attack (1:1). Safety analyses were conducted for patients who took ≥1 dose of study drug and, in some cases, those who took all 4 doses. Results: Overall, 1471 patients treated 4494 attacks. The incidences of treatment-emergent serious adverse events (SAEs) were - placebo, n=2 (0.4 %); LTN100, n=1 (0.2 %); LTN200, n=2 (0.4 %); no specific treatment-emergent SAE was reported in more than one patient. The most common treatment emergent adverse events (TEAEs) with lasmiditan were dizziness, paresthesia, fatigue, nausea, vertigo, and somnolence; the vast majority were mild or moderate in severity. The incidences of these TEAEs were highest during the first attack and decreased during subsequent attacks. For patients who experienced a common TEAE with the first attack, less than 45 % experienced the same event in subsequent attacks. Patients who did not experience an event in the 1st attack infrequently experienced the same event in subsequent attacks. The time of onset of the common TEAE ranged from ~40 min to 1 h (dependent upon TEAE) and, for individual TEAE, the onset was similar across attacks. Duration was dependent upon TEAE and attack. It was shortest for paresthesia (< 2 h for all attacks); it ranged from 1.8 to 5.5 h for other common TEAEs and was generally similar across attacks. Serotonin syndrome was reported for 2 patients post LTN dosing; there were no meaningful differences across treatment groups in suicidality; there was no evidence of an increase in motor vehicle accidents. Conclusion: In this blinded, controlled, multiple-attack study, LTN was associated with generally mild or moderate CNS-related TEAEs of short duration. TEAEs tended to decrease in frequency across the 4 attacks. Trial registration: NCT0367081