Tonner P H, Scholz J, Koch C, Schulte am Esch J
Department of Anesthesiology, University Hospital Eppendorf, Hamburg, Germany.
Anesth Analg. 1997 Mar;84(3):618-22. doi: 10.1097/00000539-199703000-00029.
To test the hypothesis that the anesthetic action of dexmedetomidine is similar to that of other anesthetics, dexmedetomidine was studied using two classical descriptors of anesthesia, the Meyer-Overton correlation and the pressure reversal of anesthesia. The anesthetic potency of dexmedetomidine and its isomer, levomedetomidine, were determined in Xenopus laevis tadpoles. Anesthesia was defined as loss of righting reflex. Octanol/water partition coefficients were determined using ultraviolet absorbance spectrophotometry. Pressure experiments were performed at pressures ranging from 1 to 91 atmospheres absolute (ata). A concentration-response curve was obtained with a half-maximum effective concentration (EC50) of dexmedetomidine of 7.1 +/- 1.1 microM (mean +/- SEM), whereas levomedetomidine showed an EC50 of 59.3 +/- 5.5 microM. The octanol/water partition coefficient was 206 +/- 49. With increasing pressure, the EC50 of dexmedetomidine increased linearly up to a value of 23.9 +/- 3.2 microM at 91 ata. Correlation of lipid solubility and anesthetic potency demonstrates that dexmedetomidine does not adhere to the Meyer-Overton rule. However, the anesthetic action of dexmedetomidine is diminished by increased pressures, thus demonstrating a similar effect compared with other general anesthetics.
为了验证右美托咪定的麻醉作用与其他麻醉药相似这一假说，使用麻醉的两个经典描述指标——迈耶-奥弗顿相关性和麻醉的压力逆转，对右美托咪定进行了研究。在非洲爪蟾蝌蚪中测定了右美托咪定及其异构体左美托咪定的麻醉效能。麻醉定义为翻正反射消失。使用紫外吸收分光光度法测定正辛醇/水分配系数。在绝对压力1至91个大气压（ata）范围内进行压力实验。获得了右美托咪定的浓度-反应曲线，其半数有效浓度（EC50）为7.1±1.1微摩尔（平均值±标准误），而左美托咪定的EC50为59.3±5.5微摩尔。正辛醇/水分配系数为206±49。随着压力增加，右美托咪定的EC50线性增加，在91ata时达到23.9±3.2微摩尔的值。脂溶性与麻醉效能的相关性表明，右美托咪定不符合迈耶-奥弗顿规则。然而，右美托咪定的麻醉作用会因压力增加而减弱，因此与其他全身麻醉药相比显示出类似的效应。
