Abstract
BACKGROUND: While different anesthetic drugs induce distinct electrical characteristics in the anesthetized brain, the effects of different anesthetics on the activity of single neurons in the central nervous system remain unclear. METHOD: In this study, mice were anesthetized with different agents (Remimazolam [REM], dexmedetomidine [DEX], and propofol [PRO]), and cortical electroencephalogram (EEG) and neuronal calcium signals were recorded before, during, and after anesthesia, followed by analysis of the changes in the power spectra of the EEG signals and the intensities of the neuronal calcium signals. RESULT: Compared with awake mice, mice under PRO-induced anesthesia primarily exhibited changes in low-frequency range brain electrical activity, whereas mice under REM-induced anesthesia exhibited significant increases in the power density in the low- and mid-frequency ranges (δ, θ, and α) postanesthesia, with minimal impact on the high-frequency (β) range. DEX not only suppressed brain cortical activity in the low-frequency range but also affected the mid-frequency range, indicating a broader effect. Reduced rates of transient calcium frequencies per minute were observed, as were reductions in the peak amplitudes of calcium activity (ΔF/F) and total signal intensity of calcium activity (ΔF/F) in anesthetized mice, with PRO showing more pronounced inhibition of neuronal calcium activity than REM and DEX did. These results demonstrate that propofol (PRO) exerts the strongest inhibitory effect on neuronal calcium activity during anesthesia, significantly suppressing transient calcium frequencies, peak amplitudes (ΔF/F), and total signal intensity (ΔF/F) compared to REM and DEX. CONCLUSION: PRO primarily enhanced low-frequency δ oscillations in EEG during anesthesia, while REM increased low- to mid-frequency (δ, θ, α) power, and DEX broadly suppressed both low- and mid-frequency bands (δ, θ, α, β). These findings highlight PRO as the most potent suppressor of neuronal excitability during the maintenance phase of anesthesia.