Department of Anesthesiology, School of Stomatology, Fourth Military Medical University, Xi'an 710032, China.
Neurosci Lett. 2009 Dec 31;467(3):247-51. doi: 10.1016/j.neulet.2009.10.052. Epub 2009 Oct 22.
Though widely used in anesthesia for many years, the mechanism underlying propofol anesthesia on human is not clear. Animal studies have already demonstrated that propofol functioned mainly by affecting neurotransmitters release. In our study, 10 healthy volunteers ranging from 20 to 40 years old were enrolled. With the help of target-controlled infusion pump, propofol was delivered intravenously. The target-controlled concentration (TCC) of propofol was gradually elevated from 0.5 to 3.0 microg/ml (for 6 steps with an increment of 0.5 microg/ml). During each step the Observer's Assessment of Alertness/Sedation Scale (OAA/S) was performed to evaluate asleep to awake/alert status. Magnetic resonance spectroscopy (MRS) was performed to evaluate neurotransmitters (choline compounds (Cho), creatine (Cr), glutamate (GLU), gamma-aminobutyric acid (GABA) and N-acetyl aspartate (NAA)) changes in brains following propofol anesthesia. OAA/S scoring showed that when the TCCs of propofol were 0, 1.5 and 3.0 microg/ml, the volunteers were in awake, sedative and unconscious, respectively. Significantly down-regulated Cho and GLU, but up-regulated GABA was observed in unconscious state in all the detected regions. NAA was decreased in unconscious status only in the hippocampus and thalamus. There was no obvious change in Cr levels in any statuses or brain regions. Our results indicate that propofol has an impact on the levels of neurotransmitters such as NAA, GLU, GABA and Cho in normal human brain. During propofol anesthesia, enhancement of inhibition or suppression of excitation may each play key roles in different brain regions.
虽然丙泊酚在麻醉中已广泛应用多年，但它对人类麻醉的作用机制尚不清楚。动物研究已经表明，丙泊酚主要通过影响神经递质的释放起作用。在我们的研究中，纳入了 10 名年龄在 20 岁至 40 岁之间的健康志愿者。通过靶控输注泵静脉输注丙泊酚。丙泊酚的靶控浓度（TCC）逐渐从 0.5 升至 3.0μg/ml（分为 6 步，每次增加 0.5μg/ml）。在每一步中，都进行观察者警觉/镇静评分（OAA/S）以评估从清醒到入睡/警觉的状态。磁共振波谱（MRS）用于评估丙泊酚麻醉后脑内神经递质（胆碱化合物（Cho）、肌酸（Cr）、谷氨酸（GLU）、γ-氨基丁酸（GABA）和 N-乙酰天冬氨酸（NAA））的变化。OAA/S 评分显示，当丙泊酚的 TCC 为 0、1.5 和 3.0μg/ml 时，志愿者分别处于清醒、镇静和无意识状态。在所有检测到的区域，均观察到无意识状态下 Cho 和 GLU 显著下调，而 GABA 上调。在无意识状态下，NAA 仅在海马体和丘脑减少。在任何状态或脑区，Cr 水平均无明显变化。我们的结果表明，丙泊酚对正常人大脑神经递质如 NAA、GLU、GABA 和 Cho 的水平有影响。在丙泊酚麻醉期间，抑制或抑制兴奋的增强可能在不同脑区起关键作用。
