In vivo imaging reveals a synchronized correlation among neurotransmitter dynamics during propofol and sevoflurane anesthesia.

General anesthesia is widely applied in clinical practice. However, the precise mechanism of loss of consciousness induced by general anesthetics remains unknown. Here, we measured the dynamics of five neurotransmitters, including γ-aminobutyric acid, glutamate, norepinephrine, acetylcholine, and dopamine, in the medial prefrontal cortex and primary visual cortex of C57BL/6 mice through in vivo fiber photometry and genetically encoded neurotransmitter sensors under anesthesia to reveal the mechanism of general anesthesia from a neurotransmitter perspective. Results revealed that the concentrations of γ-aminobutyric acid, glutamate, norepinephrine, and acetylcholine increased in the cortex during propofol-induced loss of consciousness. Dopamine levels did not change following the hypnotic dose of propofol but increased significantly following surgical doses of propofol anesthesia. Notably, the concentrations of the five neurotransmitters generally decreased during sevoflurane-induced loss of consciousness. Furthermore, the neurotransmitter dynamic networks were not synchronized in the non-anesthesia groups but were highly synchronized in the anesthetic groups. These findings suggest that neurotransmitter dynamic network synchronization may cause anesthetic-induced loss of consciousness.

Propofol exerts anti-anhedonia effects via inhibiting the dopamine transporter.

Lasker's award-winning drug propofol is widely used in general anesthesia. The recreational use of propofol is reported to produce a well-rested feeling and euphoric state; yet, the neural mechanisms underlying such pleasant effects remain unelucidated. Here, we report that propofol actively and directly binds to the dopamine transporter (DAT), but not the serotonin transporter (SERT), which contributes to the rapid relief of anhedonia. Then, we predict the binding mode of propofol by molecular docking and mutation of critical binding residues on the DAT. Fiber photometry recording on awake freely moving mice and [18F] FP-CIT-PET scanning further establishes that propofol administration evokes rapid and lasting dopamine accumulation in nucleus accumbens (NAc). The enhanced dopaminergic tone drives biased activation of dopamine-receptor-1-expressing medium spiny neurons (D1-MSNs) in NAc and reverses anhedonia in chronically stressed animals. Collectively, these findings suggest the therapeutic potential of propofol against anhedonia, which warrants future clinical investigations.

Dexmedetomidine inhibits the invasion, migration, and inflammation of rheumatoid arthritis fibroblast-like synoviocytes by reducing the expression of NLRC5.

Rheumatoid arthritis (RA) is a chronic, autoimmune disease characterized by inflammatory synovitis, but its pathogenesis remains unclear. NLRC5 is a newly discovered member of the NLR family that is effective in regulating autoimmunity, inflammatory responses, and cell death processes. Dexmedetomidine (DEX) has been reported to have a variety of pharmacological effects, including anti-inflammatory and analgesic effects. However, the role of DEX in RA has not been explored. In adjuvant-induced arthritis (AA) rat models, DEX (10 µg/kg and 20 µg/kg) reduced the pathological score, the arthritis score, paw swelling volume, and the serum levels of IL-1ß, IL-6, IL-17A, and TNF-α. Moreover, by using Western blot and real-time quantitative PCR (RT-qPCR), it was demonstrated that DEX can inhibit the expression of IL-1ß, IL-6, MMP-3, MMP-9 and P-P65 in the synovial tissue of AA rats. In human rheumatoid arthritis fibroblast-like synoviocytes (RA-FLSs), DEX (250 nM and 500 nM) was found to inhibit the expression of IL-1ß, IL-6, MMP-3, MMP-9, and P-P65 following stimulation with TNF-α. Moreover, DEX can inhibit the invasion and migration of RA-FLSs stimulated by TNF-α. Finally, the expression of NLRC5 in RA-FLSs and AA rat models was also reduced by DEX. After silencing NLRC5 in RA-FLSs, the expression of IL-1ß, IL-6, MMP-3, MMP-9, and P-P65, as well as the invasion and migration of cells, were significantly reduced. These results indicate that DEX inhibits the invasion, migration, and inflammation of RA-FLSs by reducing the expression of NLRC5 and inhibiting the NF-κB activation.