Neural circuits expressing the serotonin 2C receptor regulate memory in mice and humans.

Liu, Hesong; He, Yang; Liu, Hailan; Brouwers, Bas; Yin, Na; Lawler, Katherine; Keogh, Julia M; Henning, Elana et al. · Sci Adv · 2024

basic_science · Level V

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Abstract

Declined memory is a hallmark of Alzheimer's disease (AD). Experiments in rodents and human postmortem studies suggest that serotonin (5-hydroxytryptamine, 5-HT) plays a role in memory, but the underlying mechanisms are unknown. Here, we investigate the role of 5-HT 2C receptor (5-HT<sub>2C</sub>R) in regulating memory. Transgenic mice expressing a humanized <i>HTR2C</i> mutation exhibit impaired plasticity of hippocampal ventral CA1 (vCA1) neurons and reduced memory. Further, 5-HT neurons project to and synapse onto vCA1 neurons. Disruption of 5-HT synthesis in vCA1-projecting neurons or deletion of 5-HT<sub>2C</sub>Rs in the vCA1 impairs neural plasticity and memory. We show that a selective 5-HT<sub>2C</sub>R agonist, lorcaserin, improves synaptic plasticity and memory in an AD mouse model. Cumulatively, we demonstrate that hippocampal 5-HT<sub>2C</sub>R signaling regulates memory, which may inform the use of 5-HT<sub>2C</sub>R agonists in the treatment of dementia.

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