PT  - JOURNAL ARTICLE
AU  - Yang, Xiaoxuan
AU  - Zhu, Shan
AU  - Xia, Miaoyun
AU  - Sun, Le
AU  - Li, Sha
AU  - Xiang, Peishan
AU  - Li, Funing
AU  - Deng, Qiusui
AU  - Chen, Lijun
AU  - Zhang, Wei
AU  - Wang, Ying
AU  - Li, Qiang
AU  - Lyu, Zhuochen
AU  - Du, Xufei
AU  - Du, Jiulin
AU  - Yang, Qianzi
AU  - Luo, Yan
TI  - The Serotonergic Dorsal Raphe Promotes Emergence from Propofol Anesthesia in Zebrafish
AID  - 10.1523/JNEUROSCI.2125-23.2025
DP  - 2025 Feb 12
TA  - The Journal of Neuroscience
PG  - e2125232025
4099  - http://www.jneurosci.org/content/early/2025/02/11/JNEUROSCI.2125-23.2025.short
4100  - http://www.jneurosci.org/content/early/2025/02/11/JNEUROSCI.2125-23.2025.full
AB  - The mechanisms through which general anesthetics induce loss of consciousness remain unclear. Previous studies have suggested that dorsal raphe nucleus serotonergic (DRN5-HT) neurons are involved in inhalational anesthesia, but the underlying neuronal and synaptic mechanisms are not well understood. In this study, we investigated the role of DRN5-HT neurons in propofol-induced anesthesia in larval zebrafish (sex undetermined at this developmental stage) using a combination of in vivo single-cell calcium imaging, two-photon laser ablation, optogenetic activation, in vivo glutamate imaging and in vivo whole-cell recording. We found that calcium activity of DRN5-HT neurons reversibly decreased during propofol perfusion. Ablation of DRN5-HT neurons prolonged emergence from 30 μM propofol anesthesia, while induction times were not affected under concentrations of 1 μM, 3 μM, and 30 μM. Additionally, optogenetic activation of DRN5-HT neurons strongly promoted emergence from propofol anesthesia. Propofol application to DRN5-HT neurons suppressed both spontaneous and current injection-evoked spike firing, abolished spontaneous excitatory postsynaptic currents, and decreased membrane input resistance. Presynaptic glutamate release events in DRN5-HT neurons were also abolished by propofol. Furthermore, the hyperpolarization of DRN5-HT neurons caused by propofol was abolished by picrotoxin, a GABAA receptor antagonist, which shortened emergence time from propofol anesthesia when locally applied to the DRN. Our results reveal that DRN5-HT neurons in zebrafish are involved in the emergence from propofol anesthesia by inhibiting presynaptic excitatory glutamate inputs and inducing GABAA receptor-mediated hyperpolarization.Significance Statement The neural mechanisms of general anesthesia remain unclear. We studied the role of the dorsal raphe nucleus serotonergic (DRN5-HT) neurons in propofol anesthesia using larval zebrafish, employing in vivo calcium imaging at single-neuron resolution, two-photon ablation, optogenetic activation, and in vivo whole-cell recording. We found that the DRN5-HT neurons are involved in emergence from anesthesia, but not induction. Propofol suppresses DRN5-HT activity by inhibiting the activity of DRN5-HT neurons via GABAA receptors and blocking presynaptic excitatory glutamate inputs. These findings further support larval zebrafish as an ideal model for investigating the mechanisms of general anesthesia.