The circadian rhythm of 5-HT biosynthetic and degradative enzymes in immortalized mouse neuroendocrine pineal cell line–a model for studying circadian rhythm

Lam, Philip Y.; Chen, Kevin; Shih, Jean C.

doi:10.1016/j.lfs.2004.04.052

Cited by 2 publications

(1 citation statement)

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“…The role of Arc in synaptic plasticity and learning has been extensively studied, but its diurnal variation has been less examined. Arc expression has been shown to differ between time-points (night vs. day) in pineal cells (Yeung Lam et al, 2004 ), and is involved in circadian phase-shift in response to light in the SCN (Nishimura et al, 2003 ). In PFC, Arc mRNA shows diurnal variation, with higher expression at ZT1 vs. ZT11, indicating that transcription of Arc is regulated by a diurnal component in this brain structure (Calabrese et al, 2011 ).…”

Section: Discussionmentioning

confidence: 99%

No Escaping the Rat Race: Simulated Night Shift Work Alters the Time-of-Day Variation in BMAL1 Translational Activity in the Prefrontal Cortex

Marti

Patil

Mrdalj

et al. 2017

Front. Neural Circuits

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Millions of people worldwide work during the night, resulting in disturbed circadian rhythms and sleep loss. This may cause deficits in cognitive functions, impaired alertness and increased risk of errors and accidents. Disturbed circadian rhythmicity resulting from night shift work could impair brain function and cognition through disrupted synthesis of proteins involved in synaptic plasticity and neuronal function. Recently, the circadian transcription factor brain-and-muscle arnt-like protein 1 (BMAL1) has been identified as a promoter of mRNA translation initiation, the most highly regulated step in protein synthesis, through binding to the mRNA “cap”. In this study we investigated the effects of simulated shift work on protein synthesis markers. Male rats (n = 40) were exposed to forced activity, either in their rest phase (simulated night shift work) or in their active phase (simulated day shift work) for 3 days. Following the third work shift, experimental animals and time-matched undisturbed controls were euthanized (rest work at ZT12; active work at ZT0). Tissue lysates from two brain regions (prefrontal cortex, PFC and hippocampus) implicated in cognition and sleep loss, were analyzed with m7GTP (cap) pull-down to examine time-of-day variation and effects of simulated shift work on cap-bound protein translation. The results show time-of-day variation of protein synthesis markers in PFC, with increased protein synthesis at ZT12. In the hippocampus there was little difference between ZT0 and ZT12. Active phase work did not induce statistically significant changes in protein synthesis markers at ZT0 compared to time-matched undisturbed controls. Rest work, however, resulted in distinct brain-region specific changes of protein synthesis markers compared to time-matched controls at ZT12. While no changes were observed in the hippocampus, phosphorylation of cap-bound BMAL1 and its regulator S6 kinase beta-1 (S6K1) was significantly reduced in the PFC, together with significant reduction in the synaptic plasticity associated protein activity-regulatedcytoskeleton-associated protein (Arc). Our results indicate considerable time-of-day and brain-region specific variation in cap-dependent translation initiation. We concludethat simulated night shift work in rats disrupts the pathways regulating the circadian component of the translation of mRNA in the PFC, and that this may partly explain impaired waking function during night shift work.

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Section: Discussionmentioning

confidence: 99%

No Escaping the Rat Race: Simulated Night Shift Work Alters the Time-of-Day Variation in BMAL1 Translational Activity in the Prefrontal Cortex

Marti

Patil

Mrdalj

et al. 2017

Front. Neural Circuits

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Analyzing cannabinoid-induced abnormal behavior in a zebrafish model

Hasumi

Maeda

Yoshida

2020

Preprint

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This study investigated the locomotor activity and responses under stressful conditions to assess marijuana-induced abnormal behavior in zebrafish larvae (Danio rerio), as an alternative to the standard rodent model. To induce the desired symptoms, cannabidiol and WIN55,212-2, two chemical components derived from marijuana plants, were used. A repeated light and dark test was used to assess how drug exposure influenced locomotive responses. Subjects were examined after moderate cannabidiol and WIN55,212-2 exposure and 24 h after relocation into untreated water. Cannabidiol did not produce a dose-dependent inhibitory effect on locomotor activity; 0.5 and 10 μg/mL cannabidiol decreased total distance and velocity, and 10 μg/mL cannabidiol attenuated responses in the darkness. No differences between the control and cannabidiol-treated groups were apparent after 24 h in fresh water. WIN55,212-2 at 0.5 and 1 μg/mL almost completely stopped fish activity even in darkness and at 10 μg/mL induced mortality. Spending 24 h in fresh water almost reversed drug-induced immobilization, even in WIN55,212-2-treated groups. Subjects were evaluated for responses to additional cannabidiol after WIN55,212-2 exposure. Cannabidiol attenuated WIN55,212-2-induced abnormal immobilization, whereas commensurate doses of cannabidiol and WIN55,212-2 produced a mixed response. In conclusion, the behavioral effects of marijuana depend on the ratio of the two different cannabinoid properties. The repeated light and dark test might be a suitable method for drug-induced behavioral assay.

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The circadian rhythm of 5-HT biosynthetic and degradative enzymes in immortalized mouse neuroendocrine pineal cell line–a model for studying circadian rhythm

Cited by 2 publications

References 37 publications

No Escaping the Rat Race: Simulated Night Shift Work Alters the Time-of-Day Variation in BMAL1 Translational Activity in the Prefrontal Cortex

No Escaping the Rat Race: Simulated Night Shift Work Alters the Time-of-Day Variation in BMAL1 Translational Activity in the Prefrontal Cortex

Analyzing cannabinoid-induced abnormal behavior in a zebrafish model

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