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Intravenous ketamine for long term anesthesia in rats
Robert A Linsenmeier1,2, Lisa Beckmann1, Andrey V Dmitriev1
1Department of Biomedical Engineering, Northwestern University, Evanston, IL, USA.
Heliyon
|December 28, 2020
Summary
For long-term anesthesia in rats, intravenous ketamine/xylazine dosing must account for weight. A specific allometric relationship is identified, optimizing anesthetic levels and minimizing neural response depression in research animals.
Area of Science:
- Veterinary Anesthesiology
- Neuroscience Research
Background:
- Ketamine/xylazine anesthesia is used for animal procedures, but optimal dosing for prolonged experiments remains debated.
- Previous studies show discrepancies in effective doses for long-duration anesthesia in rats.
Purpose of the Study:
- To resolve discrepancies in ketamine/xylazine dosing for extended anesthesia in rats.
- To establish an allometric relationship for intravenous ketamine/xylazine dosage based on rat weight.
Main Methods:
- Adult Long-Evans rats underwent terminal experiments lasting 10 hours under continuous intravenous ketamine/xylazine infusion.
- Anesthetic doses were adjusted to minimize effects while maintaining anesthesia.
- An allometric model was fitted to dose-weight data and compared with prior research.
Main Results:
- An allometric relationship was established: dose = 9.13 (weight)-1.213 (r2 = 0.73), with xylazine at 3.3% of ketamine dose.
- This relationship reconciles prior discrepancies attributed to variations in rat sizes.
- Ketamine at these doses still depressed electroretinogram responses compared to urethane anesthesia.
Conclusions:
- Intravenous ketamine dosing in rats for prolonged anesthesia requires weight-adjusted, allometric calculations.
- Utilizing weight-specific doses prevents excessive neural response depression.
- This optimized dosing strategy is crucial for reliable long-term animal research.
