The role of the dorsomedial periaqueductal gray glutamatergic neurons in promoting arousal under multiple general anesthetics in mice.
Summary
dmPAG glutamatergic neurons were suppressed by diverse anesthetics and activated during wakefulness. Optogenetic/chemogenetic activation delayed induction, hastened emergence, and reduced burst-suppression during maintained anesthesia; inhibition enhanced anesthetic effects across agents, suggesting a shared arousal substrate.
Key Findings
- dmPAG glutamatergic activity is suppressed during anesthesia and elevated during wakefulness across sevoflurane, propofol, ketamine, and dexmedetomidine.
- Optogenetic activation prolonged induction (≈219 vs 373 s) and shortened emergence (≈231 vs 135 s) under sevoflurane (both P<0.001).
- Activation induced wake-like EEG with a markedly reduced burst-suppression ratio (≈50% vs 2.15%, P<0.001); inhibition potentiated anesthetic effects across agents.
Clinical Implications
Targeting dmPAG glutamatergic circuits could inform pharmacologic or neuromodulatory approaches to accelerate emergence or counter delayed awakening, though translation from mice to humans remains to be established.
Why It Matters
This study identifies a convergent neural circuit modulating anesthetic depth and emergence across distinct agents, offering a mechanistic substrate for future targeted arousal strategies.
Limitations
- Preclinical mouse model limits direct clinical translation.
- Detailed sample sizes and potential off-target effects of neuromodulation are not fully delineated in the abstract.
Future Directions
Test dmPAG-targeted neuromodulation/pharmacology in large animals and explore biomarkers of dmPAG activity during anesthesia to guide individualized emergence protocols.
Study Information
- Study Type
- Basic/Mechanistic Research
- Research Domain
- Pathophysiology
- Evidence Level
- V - Preclinical in vivo mechanistic experiments in mice elucidating neural circuitry.
- Study Design
- OTHER