Eger E I, Koblin D D, Laster M J, Schurig V, Juza M, Ionescu P, Gong D
Department of Anesthesia, University of California, San Francisco 94143-0464, USA.
Anesth Analg. 1997 Jul;85(1):188-92. doi: 10.1097/00000539-199707000-00033.
Results of in vivo and in vitro studies of the anesthetic potencies of the enantiomers (optical isomers) of isoflurane provide various results ranging from no difference to differences of nearly two fold. A finding of a difference in anesthetic requirement in the whole animal has particular relevance to theories of anesthetic mechanisms of action because it suggests that anesthesia may result from a specific anesthetic-receptor interaction. This led to our decision to redetermine the minimum alveolar anesthetic concentration (MAC) of (+)-S and (-)-R enantiomers of isoflurane in 12 Sprague-Dawley rats (six per group). The (+)-S enantiomer gave a MAC of 0.0144 +/- 0.0012 atm (i.e., 1.44% +/- 0.12% at 1 atm pressure; mean +/- SD) and the (-)-R enantiomer gave a MAC of 0.0169 +/- 0.0020 atm. Although the 17% greater value for the (-)-R enantiomer is qualitatively consistent with previous results the difference is not significant (P = 0.06), and the absolute difference is smaller than that found by a previous study. However, given the small sample size, our power to define a small significant difference is limited. Regardless of statistical significance, our results do not confirm the conclusion that interaction with a specific receptor is important to the mechanism of action of inhaled anesthetics.
异氟烷对映体（光学异构体）麻醉效能的体内和体外研究结果呈现出多样的结果，从无差异到近两倍的差异不等。在全动物中发现麻醉需求存在差异，这与麻醉作用机制的理论具有特别的相关性，因为这表明麻醉可能源于特定的麻醉剂 - 受体相互作用。这促使我们决定重新测定12只Sprague - Dawley大鼠（每组6只）中异氟烷的（+）-S和（-）-R对映体的最低肺泡麻醉浓度（MAC）。（+）-S对映体的MAC为0.0144±0.0012 atm（即1个大气压下为1.44%±0.12%；平均值±标准差），（-）-R对映体的MAC为0.0169±0.0020 atm。虽然（-）-R对映体高出17%的值在定性上与先前的结果一致，但差异并不显著（P = 0.06），且绝对差异小于先前一项研究发现的结果。然而，鉴于样本量较小，我们界定微小显著差异的能力有限。无论统计学意义如何，我们的结果都未证实与特定受体相互作用对吸入麻醉剂作用机制很重要这一结论。
