Fig. 3. Anesthetic concentration dependence of the apparent rate of Torpedo nicotinic acetylcholine receptor desensitization induced by 1 μm acetylcholine. At all concentrations studied, isoflurane, ethanol, and octanol significantly increased the apparent rate of desensitization. Conversely, cyclopropane and butane either reduced or had no effect on the apparent rate of desensitization. The MAC of isoflurane, butane, and cyclopropane were calculated as described in Methods as 0.28, 0.16, and 0.82 mm, respectively. The MAC values of ethanol (116 mm) and octanol (37 μm) are derived from Fang et al . 25*P < 0.05 versus control (no anesthetic).