Gonsowski C T, Eger E I
Department of Anesthesia, University of California, San Francisco 94143-0464.
Anesth Analg. 1994 Oct;79(4):710-2. doi: 10.1213/00000539-199410000-00016.
Recent determinations of the minimum alveolar anesthetic concentration (MAC) for nitrous oxide in rats yield values of 1.51-1.55 atm. When combined with results from other reports, these results suggest a deviation from linear additivity, and call into question the unitary theory of narcosis. The present report provides evidence that nitrous oxide does act in an additive manner. We directly determined the MAC for nitrous oxide in groups of 10 Sprague-Dawley and Long-Evans rats, using electrical stimulation of the tail or abdomen. MAC equaled 2.35 +/- 0.20 atm (mean +/- SD) in Long-Evans rats with tail stimulation; 2.21 +/- 0.19 in Sprague-Dawley rats using tail stimulation; and 1.99 +/- 0.21 atm in Sprague-Dawley rats using abdominal stimulation (tail versus abdominal stimulation was significantly different). Our MAC values are higher than those recently reported by others. Differences from the previous reports may be explained by differences in experimental design or interpretation. Our findings are consistent with an additive effect of nitrous oxide with other inhaled anesthetics (data from other reports) and thereby support the unitary theory of narcosis.
最近对大鼠氧化亚氮最低肺泡麻醉浓度（MAC）的测定得出的值为1.51 - 1.55个大气压。当与其他报告的结果相结合时，这些结果表明偏离了线性相加性，并对麻醉单一理论提出了质疑。本报告提供了氧化亚氮确实以相加方式起作用的证据。我们使用对尾巴或腹部的电刺激，直接测定了10只斯普拉格 - 道利大鼠和长 - 伊文斯大鼠组中氧化亚氮的MAC。在接受尾巴刺激的长 - 伊文斯大鼠中，MAC等于2.35±0.20个大气压（平均值±标准差）；在使用尾巴刺激的斯普拉格 - 道利大鼠中为2.21±0.19；在使用腹部刺激的斯普拉格 - 道利大鼠中为1.99±0.21个大气压（尾巴刺激与腹部刺激有显著差异）。我们的MAC值高于其他人最近报告的值。与先前报告的差异可能由实验设计或解释的不同来解释。我们的发现与氧化亚氮与其他吸入麻醉剂的相加效应（来自其他报告的数据）一致，从而支持麻醉单一理论。
