Fentanyl-fluanisone-midazolam combination results in more stable hemodynamics than does urethane alpha-chloralose and 2,2,2-tribromoethanol in mice

Near-physiologic hemodynamic conditions for several hours were needed to study cardiovascular physiology in a murine model. We compared two commonly used anesthetic treatments, urethane alpha-chloralose (U-alphaCh; 968 mg U and 65 mg alphaCh/kg) and 2,2,2-tribromoethanol (TBE; 435 mg/kg) and fentanyl fluanisone midazolam (FFM; 3.313 mg fentanyl, 104.8 mg fluanisone, and 52.42 mg midazolam/kg) with respect to mean arterial blood pressure (MAP) and heart rate (HR) for 100 min at similar levels of surgical anesthesia. Assessed every 10 to 15 min, the U-alphaCh+TBE group maintained a significantly (P < 0.001) lower mean MAP (49 4 mmHg) than did the FFM group (78 5 mmHg). Mean HR in the U-alphaCh+TBE group significantly (P < 0.001) increased from 308 34 bpm at the beginning to 477 43 bpm at the end of the experiment. In comparison, the FFM group showed a stable HR of 431 37 bpm. The MAP and HR of the U-alphaCh+TBE group were extremely unstable, with sudden and unpredictable changes in MAP when examined at 1-min intervals. The results of our study show that U-alphaCh+TBE anesthesia should not be used in murine models in which stable, near-physiologic hemodynamics are needed for cardiovascular studies