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bioRxiv · 10.1101/2022.03.11.483982

Chemogenetic enhancement of cAMP signaling renders hippocampal synaptic plasticity resilient to the impact of acute sleep deprivation

Walsh, E. N.·Shetty, M. S.·Diba, K.·Abel, T.
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Abstract

Sleep facilitates memory storage and even brief periods of sleep loss lead to impairments in memory, particularly memories that are hippocampus dependent. In previous studies, we have shown that the deficit in memory seen after sleep loss is accompanied by deficits in synaptic plasticity. Our previous work has also found that sleep deprivation is associated with reduced levels of cyclic adenosine monophosphate (cAMP) in the hippocampus, and that the reduction of cAMP mediates the diminished memory performance. Based on these findings, we hypothesized that cAMP acts as a mediator for not only the cognitive deficits caused by sleep deprivation, but also the observed deficits in synaptic plasticity. In this study, we expressed the heterologous Drosophila melanogaster Gs-protein coupled octopamine receptor (DmOct{beta}1R) in mouse hippocampal neurons. This receptor is selectively activated by the systemically injected ligand (octopamine), thus allowing us to increase cAMP levels in hippocampal neurons during a five-hour sleep deprivation period. Our results show that chemogenetic enhancement of cAMP during the period of sleep deprivation prevents deficits in a persistent form of long-term potentiation (LTP) that is induced at the Schaffer collateral synapses in the hippocampal CA1 region. We also found that elevating cAMP levels only in the early or later half of sleep deprivation successfully prevented LTP deficits. These findings reveal that cAMP-dependent signaling pathways are key mediators of sleep deprivation at the synaptic level. Targeting these pathways could be useful in designing strategies to prevent the impact of sleep loss. Significance statementInsufficient sleep is an issue with significant health and socioeconomic implications. This includes a negative impact on memory consolidation. Previous studies in mice found that acute sleep deprivation leads to deficits in hippocampal synaptic plasticity and memory, which are associated with reduced levels of the signaling molecule cAMP. In this study, we used a chemogenetic strategy to enhance cAMP levels in specific hippocampal neurons during sleep deprivation. We found that this made synaptic plasticity resilient to the negative effects of sleep deprivation. These findings reveal that cAMP-dependent signaling pathways are key mediators of sleep deprivation and that targeting these pathways could be useful in designing strategies to prevent the impact of sleep loss.

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Walsh, E. N., Shetty, M. S., Diba, K., Abel, T.. 2022-03-14. Chemogenetic enhancement of cAMP signaling renders hippocampal synaptic plasticity resilient to the impact of acute sleep deprivation. https://doi.org/10.1101/2022.03.11.483982

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