Danneman P J, Mandrell T D
Department of Comparative Medicine, University of Tennessee, Memphis, USA.
Lab Anim Sci. 1997 Aug;47(4):386-95.
Although neonatal altricial rodents are frequently used in experimental projects in which they must undergo survival surgical procedures, there are few published guidelines for anesthetizing them. Many of the drugs and methods that are commonly used to anesthetize newborn rodents provide inadequate anesthesia or are associated with problems, such as excessively high mortality. A two-part study was undertaken with the intention of identifying agents or methods that can be used to provide humane, safe, and effective anesthesia for neonatal rats. In part I, 1- to 3-day-old rat pups were anesthetized with methoxyflurane or one of several injectable agents, or by induction of hypothermia (immersion in ice water). Times to loss of the righting reflex, surgical anesthesia (indicated by loss of the pedal reflex and failure to respond to a skin incision), and recovery of the righting reflex were measured, and heart rate, respiratory rate, and oxygen saturation were monitored. Ketamine (100 mg/kg of body weight, i.p.), pentobarbital (30 to 40 mg/kg, i.p.), and fentanyl-droperidol combination (0.16 mg of fentanyl and 8.0 micrograms of droperidol/g, i.p.) proved unsafe (> 50% mortality) and/or ineffective at inducing short-term surgical anesthesia. In contrast, methoxyflurane and hypothermia were safe and effective. On the basis of subjective observations that they struggled and vocalized less, pups placed in protective latex sleeves prior to immersion in ice water appeared to be less distressed than pups immersed unprotected. In part II of the study, it was possible to safely maintain 1- to 3-day-old pups at a surgical plane of anesthesia for 30 min with either methoxyflurane or hypothermia. Supplementation with pentobarbital (20 mg/kg, i.p.) offered no advantages but significantly prolonged time to recovery. Surviving pups in both studies grew at similar rates during the month after testing. It was concluded that methoxyflurane or hypothermia are good choices for short- or long-term anesthesia of neonatal rats, and that use of a protective sleeve appears to reduce distress associated with induction of profound hypothermia.
尽管新生的未成熟啮齿动物经常被用于必须接受存活手术的实验项目中，但关于麻醉它们的公开指南却很少。许多常用于麻醉新生啮齿动物的药物和方法提供的麻醉效果不足，或者存在问题，比如死亡率过高。进行了一项分为两部分的研究，旨在确定可用于为新生大鼠提供人道、安全且有效的麻醉的药物或方法。在第一部分中，用甲氧氟烷、几种注射剂中的一种，或者通过诱导低温（浸入冰水中）对1至3日龄的幼鼠进行麻醉。测量了翻正反射消失时间、手术麻醉时间（以足趾反射消失和对皮肤切口无反应来表示）以及翻正反射恢复时间，并监测了心率、呼吸频率和血氧饱和度。氯胺酮（100毫克/千克体重，腹腔注射）、戊巴比妥（30至40毫克/千克，腹腔注射）以及芬太尼-氟哌利多合剂（0.16毫克芬太尼和8.0微克氟哌利多/克，腹腔注射）被证明不安全（死亡率>50%）和/或在诱导短期手术麻醉方面无效。相比之下，甲氧氟烷和低温是安全有效的。基于主观观察，即在浸入冰水中之前置于保护性乳胶套筒中的幼鼠挣扎和发声较少，它们似乎比未受保护而浸入水中的幼鼠痛苦更小。在研究的第二部分中，用甲氧氟烷或低温可以安全地将1至3日龄的幼鼠维持在手术麻醉平面30分钟。补充戊巴比妥（20毫克/千克，腹腔注射）没有优势，但显著延长了恢复时间。两项研究中存活的幼鼠在测试后的一个月内生长速度相似。得出的结论是，甲氧氟烷或低温是新生大鼠短期或长期麻醉的良好选择，并且使用保护套筒似乎可以减少与深度低温诱导相关的痛苦。
