丙泊酚对机械性刺激作用脑区的影响

摘要

目的 观察不同浓度丙泊酚对机械性刺激作用脑区的影响,探讨丙泊酚的镇痛作用.方法 将20名健康志愿者随机分为浅麻醉组和深麻醉组,采用功能性磁共振成像(fMRI)进行检测,fMRI扫描序列=结构像扫描+功能像扫描,其中功能像扫描=(20 son+20 s off)×6次机械性刺激(P1)+靶控输注(TCI)不同浓度丙泊酚+重复机械性刺激(P2).结果 浅麻醉组(第2次刺激-第1次刺激,即P2-P1)fMRI下显示激活脑区为扣带回、丘脑、小脑,(第1次刺激-第2次刺激,即P1 -P2)fMRI下显示激活颞叶、额叶、枕叶；深麻醉组(P2-P1)小脑明显激活,(P1-P2)可见扣带回和丘脑激活.TCI丙泊酚后,给予P2,(深麻醉组-浅麻醉组)可见小脑激活.结论 不同浓度丙泊酚对脑区的激活不同,丙泊酚可能通过不同作用机制发挥镇痛作用.%Objective To observe the effects of different concentrations of propofol on brain regions activated by mechanical stimuli, and then to investigate the analgesic effect of propofol. Methods Twenty healthy male volunteers were randomly divided into two groups: light anesthesia group (group L) (BIS 60-80) and deep anesthesia group (group D) ( BIS 40-60). Propofol was administrated by target controlled infusion system in pilot study. The target effect site concentration ( ESC) of propofol was defined as the average of the ESC from BIS 80 to 60 or BIS 60 to 40 in group L or group D respectively. Mechanical stimuli were applied using von Frey filaments at the center of the left foot, and the pain threshold and VAS scores were evaluated. fMRI examinations were taken 1 week after pilot study with the following sequences: structure imaging + functional imaging; functional iiaaging = stimulus sequence + propofol sequence, in which the stimulus sequence was 6 x ( 20 8 on + 20 s off). This sequence was repeated after propofol sequence. Results As shown by fMRI, in group L, active brain regions of (the second stimulation-the first stimulation, P2-P1) were seen in cingulate gyros, thal-amus, and cerebellum, while active brain regions of (P1-P2) were seen in temporal lobe, frontal gyrus, and occipital lobe. In group D, the active brain region of (P2-P1) was only seen in cerebellum, while active brain regions of (P1 -P2) were seen in cingulate gyms and thalamus. Active brain regions of (deep-low) with propo-fol infusion in response to vFFs stimulation were observed in cerebellum. Conclusions Propofol at different concentrations has different effect on the activation of brain reions. It may exert its analgesic effect via different mechanisms.