Hypothalamus Neurons Steer Post-Anesthesia Sleep Disruption Through Cannabinoid Signaling

A single two-hour session of isoflurane anesthesia is enough to scramble a mouse’s sleep for the rest of the next day, and researchers now report that two opposing populations of neurons in a small hypothalamic nucleus control that disruption in strikingly different ways. In a study published in Anesthesiology and Perioperative Science, a team based at the Fourth Military Medical University in China shows that glutamatergic and GABAergic neurons in the dorsomedial hypothalamus, or DMH, regulate post-anesthesia sleep disturbance through distinct, cannabinoid type 1 receptor-dependent presynaptic mechanisms. The work, conducted entirely in male mice, identifies the CB1 receptor as a potential therapeutic target for a problem that affects more than half of surgical patients.

Postoperative sleep disturbance is one of the most common complications of surgery, affecting roughly 50 to 60 percent of surgical patients according to the authors. It is characterized by increased wakefulness, reduced and fragmented rapid eye movement and non-rapid eye movement sleep, and a generally disrupted sleep-wake architecture. These disturbances are not merely uncomfortable: the paper notes they are associated with increased risks of delirium, exaggerated pain perception, and cardiovascular events, ultimately delaying recovery and prolonging hospitalization. Because surgical trauma, inflammation, and pain all muddy the picture, the team deliberately focused on post-anesthesia sleep disturbance, or PSD, isolating the contribution of anesthesia itself in a mouse model that involved no surgery beyond the recording implants.

The experimental design was straightforward but technically demanding. Mines were fitted with wireless biotelemetry transmitters that recorded electroencephalography and electromyography signals continuously, allowing the researchers to score sleep and wake states in ten-second epochs before and after anesthesia. After establishing a 24-hour baseline, mice received 1.4 percent isoflurane in 100 percent oxygen for two hours at the start of their active, dark phase, from zeitgeber time 12 to zeitgeber time 13. Post-anesthesia sleep was then recorded for the following 22 hours. Chemogenetic tools, viral vectors carrying activating or inhibitory designer receptors, allowed the team to switch specific neuronal populations on or off, while fiber photometry tracked calcium activity in those neurons in real time across sleep-wake cycles.

The first key finding concerned timing. Sleep in the first several hours after anesthesia looked essentially normal. The disturbance arrived later, and preferentially during the subsequent rest phase, the light phase of the mice’s cycle. During that rest phase, total wakefulness increased significantly while both NREM and REM sleep declined, wake bouts became more numerous, NREM bouts shortened, and transitions from NREM sleep into wakefulness rose while transitions in the opposite direction fell. Even delta power, a well-established marker of deep NREM sleep quality, was significantly reduced during both the dark and light phases. The authors suggest this delayed, phase-specific pattern mirrors clinical observations in patients, whose sleep disruption typically emerges on the first night after surgery rather than immediately upon waking.

Whole-brain c-Fos mapping, performed the morning after anesthesia, revealed significantly increased neuronal activation in multiple regions, including the DMH, the medial preoptic area, the lateral and medial habenula, and the lateral mammillary body. The team homed in on the DMH, both because it was among the most strongly activated nuclei and because of its established role as an integrative hub for circadian and stress-related arousal signals. The DMH contains two principal neuronal populations: glutamatergic neurons, which promote arousal, and GABAergic neurons, which help regulate transitions between REM and NREM sleep. The researchers’ previous work had shown that both populations actively promote emergence from general anesthesia.

When the team chemogenetically activated DMH glutamatergic neurons before anesthesia, the post-anesthesia sleep-wake architecture was effectively restored to pre-anesthesia baseline levels. Activation increased wakefulness during the active phase, consistent with these neurons’ arousal-promoting role, while prolonging NREM sleep during the rest phase, reducing wake bouts there, and enhancing delta power, particularly in the light phase. Inhibition produced the opposite effect, exacerbating the sleep disturbance with more wakefulness and less NREM sleep during the rest phase. Fiber photometry added a crucial observation: DMH glutamatergic neurons showed heightened activity specifically during rest-phase wakefulness after anesthesia, with pronounced activity fluctuations during sleep-wake transitions. Because the suprachiasmatic nucleus, the brain’s master clock, indirectly projects to these neurons, the authors propose that anesthesia-induced suppression of their activity may disrupt normally phased sleep-wake transitions, explaining the circadian-phase dependence of the effect.

The GABAergic side of the circuit behaved in a genuinely surprising way. Both activation and inhibition of DMH GABAergic neurons alleviated the sleep disturbance, with activation producing the stronger effect, and neither manipulation showed the pronounced phase dependence seen with the glutamatergic population. Activation reduced wakefulness during both phases, increased NREM and REM sleep time during the rest phase, lengthened NREM bouts, increased transitions between NREM and REM sleep, and boosted delta power. Inhibition produced a milder but still significant improvement. Calcium imaging showed that GABAergic neurons were normally most active during wakefulness in the active phase, but after anesthesia their activity during rest-phase wakefulness was reduced. The authors interpret activation as restoring a circadian brake on wakefulness, while inhibition may disinhibit the sleep-promoting ventrolateral preoptic nucleus, positioning these neurons as a hub for maintaining sleep homeostasis.

To uncover the molecular machinery, the team performed single-nucleus RNA sequencing on microdissected DMH tissue collected immediately or six hours after anesthesia. The analysis flagged alterations in the retrograde endocannabinoid signaling pathway in both neuronal types. In excitatory neurons, the genes encoding the main degradation enzymes for anandamide and 2-arachidonoylglycerol, fatty acid amide hydrolase and monoacylglycerol lipase, were downregulated, suggesting increased levels of both endocannabinoids; quantitative PCR twelve hours after anesthesia confirmed the downregulation. In inhibitory neurons, anandamide degradation appeared predominantly suppressed as well. Because anesthesia and surgery are known to elevate endocannabinoid levels, and because endocannabinoids regulate sleep in a compound-, dose-, and timing-dependent manner, the authors hypothesized that altered endocannabinoid signaling contributes directly to PSD.

A pharmacological test supported that hypothesis. Microinjecting AM281, a CB1 receptor antagonist, into the DMH fifteen minutes before anesthesia significantly alleviated the sleep disturbance, nearly normalizing wakefulness, NREM sleep, and REM sleep patterns, particularly during the light phase, and further increasing delta power. REM sleep stability, however, was not fully restored, and some transition patterns remained abnormal. Combining the antagonist with chemogenetic manipulation revealed the presynaptic logic: AM281 almost completely abolished the phase-restoring effects of glutamatergic neuron activation, consistent with the antagonist disinhibiting GABAergic presynaptic inputs onto those neurons, while co-administration with GABAergic neuron activation worsened the disturbance, suggesting that GABAergic neurons integrate both excitatory and inhibitory presynaptic inputs to fine-tune sleep-wake stability.

The authors are careful to spell out the study’s limitations. The proposed upstream circuits, involving inputs from the subparaventricular zone and the ventrolateral preoptic nucleus, remain to be directly mapped. CB1 receptors sit on both neuronal and astrocytic membranes and on mitochondria, and the sequencing data hinted that clock-gene changes after anesthesia occurred in astrocytes rather than DMH neurons, leaving open a glial contribution. The observation window covered only a single post-anesthesia day, and only male mice were studied. All interventions were delivered before anesthesia, yet their effects outlasted the drugs’ expected therapeutic windows, a puzzle the authors address with hypotheses about preconditioning and endocannabinoid rebound rather than settled conclusions. Even so, the study delivers a coherent mechanistic framework: two cell types in one hypothalamic nucleus, governed by a single receptor system, jointly sculpting the fragmented sleep that follows anesthesia, and pointing toward CB1 receptor signaling as a target worth pursuing for the sleep disruption that so many surgical patients know firsthand.

Subject of Research: How dorsomedial hypothalamus neurons regulate post-anesthesia sleep disturbance through cannabinoid CB1 receptor signaling in mice

Article Title: DMH glutamatergic and GABAergic neurons differentially regulate post-anesthesia sleep disturbance through CB1R signaling

Article References: Wang, J., Zhou, F., Zhang, X., Jia, S., Liu, H., Fei, X., Yin, L., Zhang, Z., Liu, Y., Fang, Y., Dong, H., Lu, Z., & Zhong, H. (2026). DMH glutamatergic and GABAergic neurons differentially regulate post-anesthesia sleep disturbance through CB1R signaling. Anesthesiology and Perioperative Science, 4(1), Article 39. https://doi.org/10.1007/s44254-026-00185-y

Image Credits: AI Generated

DOI: 10.1007/s44254-026-00185-y

Keywords: post-anesthesia sleep disturbance, dorsomedial hypothalamus, isoflurane, glutamatergic neurons, GABAergic neurons, CB1 receptor, endocannabinoid system, chemogenetics, fiber photometry, single-nucleus RNA sequencing, sleep architecture, delta power