Objective Different propofol dosages have different action-sites in the brain. This study intends to dynamically observe the role of propofol in the brain and further explore its sedation mechanism.
Methods Twelve healthy volunteers were recruited in the study in the 18 - 40 age range, six males and six females, BMI 20-55 kg/m2, ASA physical status Ⅰ. When no propofol infusion, a resting-state functional magnetic resonance imaging (RS-fMRI) was acquired. The initial Ce was set at 0.5 μg/ml and kept 5 min for equilibrium, then another RS-fMRI was acquired. After each scanning, a 0.5 μg/ml rising was achieved, and a RS-fMRI was acquired at each concentration until Ramsay sedation scale achieved 6. The comparative analysis of regional homogeneity (ReHo) of whole brain was performed.
Results Compared with waking state, the ReHo values of posterior cerebellum lobe, lingual lobe, occipital lobe and temporal lobe were significantly increased (P < 0.05), and the ReHo values of anterior cingulate gyrus, precentral gyrus and frontal lobe were significantly decreased when Ce raised to 0.5 μg/ml (P < 0.05). Compared with Ce 0.5 μg/ml, the ReHo value of frontal lobe was significantly increased (P < 0.05), and the ReHo values of posterior cerebellum lobe and parahippocampal gyrus were significantly decreased when Ce raised to 1.0 μg/ml (P < 0.05). Compared with Ce 1.0 μg/ml, the ReHo values of precuneus gyrus, anterior cingulate gyrus and occipital lobe were significantly increased (P < 0.05), and the ReHo values of anterior cerebellum lobe, lobe, fusiform gyrus and parietal lobe were significantly decreased when Ce raised to 1.5 μg/ml (P < 0.05). Compared with Ce 1.5 μg/ml, the ReHo value of anterior/posterior cerebellum lobe and temporal lobe were significantly increased (P < 0.05), and the ReHo values of precuneus gyrus, frontal lobe and parietal lobe were significantly decreased when Ce raised to 2.0 μg/ml (P < 0.05).
Conclusion The action sites of propofol are relatively broad, involving both cortex and subcortex, which are characterized by dynamic changes in the distribution of the activating brain regions and the intensity of local brain activity. The cerebellum, cingulate gyrus and precuneus play a key role in the process of propofol sedation deepening. |
