Systematic Assessment of Well-Being in Mice for Procedures Using General Anesthesia

In keeping with the 3R Principle (Replacement, Reduction, Refinement) developed by Russel and Burch, scientific research should use alternatives to animal ...

Noninvasive EEG Recordings from Freely Moving Piglets

The method allows the recording of high-quality electroencephalograms (EEGs) from freely moving piglets directly in the pigpen. We use a one-channel ...

Freie Universität Berlin

Free University Berlin

The anxiolytic effect of ethanol is generally accepted to be involved in the development of alcohol dependence. Because serotonin (5-HT) is said to be involved in both anxiety and alcohol dependence, in the present study the effect of acute ethanol administration on basal 5-HT release of the medial prefrontal cortex and its effect on 5-HT release in rats submitted to an animal model of anxiety, the elevated plus maze test, were detected in two rat strains showing a different anxiety-related behavior. Ethanol had an anxiolytic-like effect and induced an increase of basal 5-HT release in the medial prefrontal cortex in the home cage in the less anxious Wistar-Harlan rats. Both effects were not seen in the more anxious Wistar-BgVV rats. The exposure to the elevated plus maze test induced an increase of extracellular 5-HT in the more anxious Wistar-BgVV rats but not in the less anxious Wistar-Harlan rats. Ethanol did not change 5-HT release during the elevated plus maze test in both rat strains. Thus, the anxiolytic-like effect of ethanol in Wistar-Harlan rats was not primarily associated with a decrease of 5-HT release in the prefrontal cortex as it is seen with other anxiolytic agents like diazepam.

Acute effect of ethanol on anxiety and 5-HT in the prefrontal cortex of rats.

In behavioral studies, food deprivation protocols are routinely used to initiate or maintain motivational states that are required in a particular test situation. However, there is limited evidence as to when food deprivation compromises animal welfare. This study investigated the effects of different lengths of food deprivation periods and restricted (fixed-time) feeding on body weight loss as well as anxiety-related and motivated behavior in 5-6 month old male and female Wistar rats. The observed body weight loss was not influenced by sex and ranged between 4% (16 h deprivation) to approximately 9% (fixed-time feeding). Despite significant body weight loss in all groups, the motivation to eat under the aversive test conditions of the modified open field test increased only after 48 h of food deprivation. Long-lasting effects on anxiety as measured in the elevated plus maze test 24 h after refeeding have not been observed, although fixed-time feeding could possibly lead to a lasting anxiogenic effect in female rats. Overall, female rats showed a more anxiolytic profile in both tests when compared to male rats. Despite these sex differences, results suggest that food deprivation is not always paralleled by an increased motivation to feed in a conflict situation. This is an important finding as it highlights the need for tailored pilot experiments to evaluate the impact of food deprivation protocols on animals in regard to the principles of the 3Rs introduced by Russell and Burch.

Food Deprivation, Body Weight Loss and Anxiety-Related Behavior in Rats.

According to the EU Directive 2010/63, the severity of a procedure has to be classified as mild, moderate or severe. General anesthesia is thought to be mild, but the Directive does not differentiate between single and repeated anesthesia. Therefore, we investigated the impact of repeated administration of isoflurane, the most commonly used inhalation anesthetic, on the well-being of adult C57BL/6JRj mice, in comparison to single administrations and to untreated animals, when applied six times for 45 min at an interval of 3-4 days. For the animals anesthetized, excitations, phases of anesthesia, and vital parameters were monitored. Well-being after anesthesia was assessed using a behavioral test battery including luxury behavior like burrowing and nest building behavior, the Mouse Grimace Scale (MGS), the free exploratory paradigm for anxiety-related behavior, home cage activity and the rotarod test for activity, as well as food intake and body weight. Additionally, hair corticosterone and fecal corticosterone metabolites were measured. Our results show that nest building behavior, home cage activity, body weight, and corticosterone concentrations were not influenced by anesthesia, whereas changes in burrowing behavior, the MGS, food intake, and the free exploratory behavior indicated that the well-being of the mice was more affected by repeated than single isoflurane anesthesia. This effect depended on the sex of the animals, with female mice being more susceptible than male mice. However, repeated isoflurane anesthesia caused only short-term mild distress and impairment of well-being, mainly in the immediate postanesthetic period. Well-being stabilized at 8 days after the last anesthesia, at the latest. Therefore, we conclude that when using our anesthesia protocol, the severity of both single and repeated isoflurane anesthesia in C57BL/6JRj mice can be classified as mild. However, within the mild severity category, repeated isoflurane anesthesia ranks higher than single isoflurane anesthesia. Additionally, our results imply that male and female mice can differently perceive the severity of a procedure.

Silke Dietze

Institute of Pharmacology and Toxicology,
Department of Veterinary Medicine,
Institute of Pharmacology and Toxicology, Department of Veterinary Medicine

Freie Universität Berlin

Systematic Assessment of Well-Being in Mice for Procedures Using General Anesthesia

Noninvasive EEG Recordings from Freely Moving Piglets

Silke Dietze

.css-o250i3{font-size:18px;font-family:Open Sans,sans-serif;line-height:21.6px;}Institute of Pharmacology and Toxicology,Department of Veterinary Medicine,Institute of Pharmacology and Toxicology, Department of Veterinary Medicine

Freie Universität Berlin

Systematic Assessment of Well-Being in Mice for Procedures Using General Anesthesia

Noninvasive EEG Recordings from Freely Moving Piglets

Institute of Pharmacology and Toxicology,
Department of Veterinary Medicine,
Institute of Pharmacology and Toxicology, Department of Veterinary Medicine