Cross-species Analysis of 5-HT3 Receptor and CB1 Receptor Interactions in the Brain
Poster No:
1763
Submission Type:
Abstract Submission
Authors:
Muhan Li1, Yan Yu1, Xueyan Wang1, Jing Zhang1, Ying Huang2
Institutions:
1Tongji University, Shanghai, shanghai, 2Tongji University, Shanghai, Shanghai
First Author:
Co-Author(s):
Introduction:
Growing evidence shows a significant role for both 5-hydroxytryptamine 3 receptor (5-HT3R) and cannabinoid receptor 1 (CB1R) in the modulation of depression, memory, and neurogenesis within the adult hippocampus (Kondo et al., 2018; Kondo et al., 2015; Hu et al., 2023). The potential link between these two receptors has been suggested. Our previous study also showed the co-expression of 5-HT3R and CB1R within cholecystokinin (CCK)-expressing interneurons in the hippocampus in mice (Yu et al., 2022). However, the precise nature and functional implications of the potential 5-HT3R-CB1R interaction remain to be elucidated.
Methods:
Using the Genotype-Tissue Expression (GTEx) database, we analyzed the RNA expression levels in brain tissue samples from normal healthy human donors. By applying Pearson's correlation analysis method, we investigated the correlation between the expression of the 5-HT3R and the CB1R among different brain regions. Subsequently, immunofluorescence assays by confocal microscope or stimulated emission depletion (STED) nanoscopy imaging were used to analyze the co-localization of 5-HT3Rs and CB1Rs in the hippocampus in mice. To probe the functional interplay between these receptors, in vitro electrophysiological recordings were performed in hippocampal slices. Synaptosome was isolated through differential centrifugation, which served as a precursor to subsequent interaction assays. Employing molecular biological methods, including co-immunoprecipitation (Co-IP) and proximity ligation assay (PLA), we investigated whether there is a direct physical interaction between 5-HT3R and CB1R.
Results:
In our study, we found a robust positive correlation between the expression levels of 5-HT3Rs and CB1Rs in specific human brain regions, notably the hippocampus, amygdala, and cortex (Figure 1). This correlation was not observed in the cerebellum, hypothalamus, and spinal cord. In the hippocampal slices in mice, 5-HT3Rs and CB1Rs were found to be co-expressed on axon terminals, with an absence on the soma of 5-HT3R-positive interneurons (Figure 2a, b). Quantitative analysis of co-localization revealed that 87.80 ± 1.57% of 5-HT3R positive axon terminals expressed CB1Rs, and conversely, 70.69 ± 1.52% of CB1R stained axon terminals were 5-HT3R positive. The functional interplay between 5-HT3Rs and CB1Rs was further investigated through in vitro electrophysiological recordings in hippocampal slices. We found that the inhibitory effects of the 5-HT3R antagonist ondansetron on long-term potentiation (LTP) in CA1 region were abolished by the presence of the CB1R antagonist AM251. Additionally, the depolarization-induced suppression of inhibition (DSI), a canonical electrophysiological manifestation of endocannabinoid function mediated by CB1Rs, was attenuated by ondansetron, suggesting a functional interaction between 5-HT3Rs and CB1Rs. As shown in Figure 2c, 5-HT3R immunoreactivity was found in the immunocomplexes using CB1R antibody in synaptosome preparations from hippocampal tissue. Moreover, PLA fluorescent signal was detected in hippocampal slices in mice (Figure 2d), providing additional evidence for a direct physical interaction between 5-HT3Rs and CB1Rs.
Conclusions:
The 5-HT3R and the CB1R exhibit structural and functional interaction in the hippocampus of normal healthy humans and mice.
Neuroanatomy, Physiology, Metabolism and Neurotransmission:
Transmitter Receptors 1
Transmitter Systems 2
Keywords:
Cellular
ELECTROPHYSIOLOGY
Limbic Systems
Seretonin
1|2Indicates the priority used for review
Abstract Information
By submitting your proposal, you grant permission for the Organization for Human Brain Mapping (OHBM) to distribute your work in any format, including video, audio print and electronic text through OHBM OnDemand, social media channels, the OHBM website, or other electronic publications and media.
The Open Science Special Interest Group (OSSIG) is introducing a reproducibility challenge for OHBM 2025. This new initiative aims to enhance the reproducibility of scientific results and foster collaborations between labs. Teams will consist of a “source” party and a “reproducing” party, and will be evaluated on the success of their replication, the openness of the source work, and additional deliverables. Click here for more information. Propose your OHBM abstract(s) as source work for future OHBM meetings by selecting one of the following options:
Please indicate below if your study was a "resting state" or "task-activation” study.
Healthy subjects only or patients (note that patient studies may also involve healthy subjects):
Was this research conducted in the United States?
Were any human subjects research approved by the relevant Institutional Review Board or ethics panel? NOTE: Any human subjects studies without IRB approval will be automatically rejected.
Were any animal research approved by the relevant IACUC or other animal research panel? NOTE: Any animal studies without IACUC approval will be automatically rejected.
Please indicate which methods were used in your research:
Provide references using APA citation style.
Kondo, M., Koyama, Y., Nakamura, Y., & Shimada, S. (2018). A novel 5HT3 receptor–IGF1 mechanism distinct from SSRI-induced antidepressant effects. Molecular Psychiatry, 23(4), 833-842.
Kondo, M., Nakamura, Y., Ishida, Y., & Shimada, S. J. M. P. (2015). The 5-HT3 receptor is essential for exercise-induced hippocampal neurogenesis and antidepressant effects. Molecular psychiatry, 20(11), 1428-1437.
Yu, Y., Li, J. J., He, X. Q., Lai, Z. Y., Hao, R., Qi, Y., ... & Huang, Y. (2022). 5‐HT3A receptors maintain hippocampal LTP in a CB1 and GABAA receptor‐dependent manner for spatial memory. British Journal of Pharmacology, 179(12), 2969-2985.