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Updated: Jun 5, 2025
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Published on: July 29, 2014
Mouse strain-specific habituation to oral metamizole administration
Tim Schreiber1, Emily Leitner1, Jakob Brandstetter1
1Rudolf-Zenker-Institute of Experimental Surgery, University Medical Center, Germany.
Abstract:
When pain might occur during an animal experiment, sufficient analgesia is necessary. Metamizole is the third most used postoperative pain medication in animal research. The analgesic effect of metamizole is supposed to last 6-8 h in rodents. Therefore, the supplementation of drinking water with metamizole should be the preferred method to ensure permanent pain relief without unnecessary stressors. The present exploratory study compared the voluntary intake of metamizole-supplemented drinking water (3 mg/ml) between healthy mice of three different mouse strains. After the addition of metamizole to the drinking water, a marginal reduction in body weight was observed in C57BL/6J and BALB/c mice. However, NSG mice displayed a significantly higher body weight loss and reduction of drinking behavior compared with the C57BL/6J and BALB/c strains. The acceptance of metamizole in NSG mice did not increase with a different metamizole formulation. Thus, the mice of the inbred strains C57BL/6J and BALB/c seemed to be able to adapt to the taste of metamizole, while NSG mice were not able to accustom to analgesia within 1 week. Strain-specific habituation should be considered in future animal studies when analgesia is applied via drinking water.
Insights
Metamizole in drinking water provides pain relief for lab mice, but NSG mice show reduced intake and weight loss compared to C57BL/6J and BALB/c strains. Strain differences in habituation to analgesia are crucial for animal research.
Area of Science:
- Veterinary Medicine
- Pharmacology
- Animal Science
Background:
- Effective analgesia is critical in animal research to mitigate pain during experiments.
- Metamizole is a commonly used postoperative analgesic in rodents, with an expected duration of 6-8 hours.
- Supplementing drinking water with metamizole offers a method for continuous pain relief without additional stressors.
Purpose of the Study:
- To compare the voluntary intake of metamizole-supplemented drinking water across three different mouse strains.
- To assess the impact of metamizole on body weight and drinking behavior in these strains.
- To determine strain-specific habituation to metamizole in drinking water.
Main Methods:
- An exploratory study was conducted using healthy mice from three strains: C57BL/6J, BALB/c, and NSG.
- Metamizole was added to drinking water at a concentration of 3 mg/ml.
- Body weight, drinking behavior, and voluntary intake of supplemented water were monitored.
Main Results:
- C57BL/6J and BALB/c mice showed only a marginal reduction in body weight.
- NSG mice exhibited significantly greater body weight loss and reduced drinking behavior.
- NSG mice did not improve their acceptance of metamizole even with a different formulation, indicating a lack of habituation.
Conclusions:
- Mouse strain significantly influences the acceptance and efficacy of metamizole administered via drinking water.
- C57BL/6J and BALB/c mice appear to habituate to the taste of metamizole, unlike NSG mice.
- Consideration of strain-specific responses is essential when using drinking water for analgesia delivery in animal studies.
