Carbon dioxide and isoflurane are widely used for killing rats, yet may not truly achieve “euthanasia”, because they elicit aversion. The inhalant anesthetic desflurane is faster acting than isoflurane, representing a potential refinement. Using an aversion-avoidance paradigm, 24 rats were exposed to isoflurane or desflurane (n = 12 per group) at initial exposure. Fourteen rats were then re-exposed to isoflurane or desflurane (n = 7 per group), after a 7 days washout period. Initial exposure: time to recumbency was faster for desflurane than isoflurane (p = 0.0008, 95% CI [-12.9 to 32.6 s]), with 9/12 and 6/12 rats becoming recumbent, respectively. At initial exposure, there was no difference between groups in time to withdrawal (p = 0.714). At re-exposure, all rats withdrew and no rats became recumbent. Time to withdrawal at re-exposure did not differ between treatment groups (p = 0.083). Compared to initial exposure, time to withdrawal during re-exposure was similar for isoflurane (p = 0.228) and faster with desflurane (p = 0.012, 95% CI [19.1 to 49.5 s]). Isoflurane and desflurane are similarly aversive, with aversion increasing at re-exposure. The shorter time from exposure to recumbency with desflurane indicates that any distress is of a shorter duration when compared with isoflurane.

中文翻译：

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Sprague-Dawley大鼠（Rattus Norvegicus）对地氟醚和异氟烷的厌恶。

二氧化碳和异氟烷被广泛用于杀死大鼠，但由于它们引起厌恶，因此可能无法真正实现“安乐死”。吸入麻醉药地氟醚的作用比异氟烷更快，这代表了一种潜在的改进方法。使用避免规避范式，在初次暴露时，将24只大鼠暴露于异氟烷或地氟醚（每组n = 12）。在7天的冲洗期后，将十四只大鼠重新暴露于异氟烷或地氟醚（每组n = 7）。初始暴露：地氟醚的卧卧时间比异氟烷更快（p = 0.0008，95％CI [-12.9至32.6 s]），分别有9/12和6/12的大鼠卧卧。初次接触时，两组的退出时间没有差异（p= 0.714）。再暴露时，所有大鼠都退出，没有大鼠卧倒。治疗组之间再次暴露的停药时间没有差异（p = 0.083）。与初始暴露相比，异氟烷的再暴露时间与撤离时间相似（p = 0.228），而去氟醚的撤离时间则更快（p = 0.012，95％CI [19.1至49.5 s]）。异氟烷和地氟醚同样具有厌恶性，在再次接触时反感增加。从暴露到去氟醚倾倒的时间较短，表明与异氟烷相比，任何困扰的持续时间都较短。