Cardiorespiratory depression in mice receiving urethane anesthesia

Urethane is used in rats and dogs and is recognized to minimally suppress cardiorespiratory function, but little is known about its impact in mouse models. The overall purpose of this study was to comprehensively compare cardiorespiratory function in mice anesthetized with urethane, compared to conscious state. 16-week old C57BL6/J mice (n=30,15 males, 15 females), underwent measurements while conscious and urethane-anesthetized. Hemodynamic parameters including heart rate variability (HRV), blood pressure (BP), heart rate (HR), and oxygen saturation (SpO 2 ) were acquired using non-invasive (CODA and MouseOx) and invasive (Cardiac catheterization, Millar PVR-1030) techniques. All experiments were repeated with supplemental oxygen. Urethane decreased HRV and SpO 2 . Oxygen supplementation restored HRV and SpO 2 . We found no significant difference between invasive and non-invasive measurements of HRV, HR, BP, and SpO 2 . Urethane depressed BP in a sex-dependent manner. In this first report of the HRV response to urethane anesthesia in mice we found an anesthesia-induced decline in various cardiovascular parameters that is likely the result of urethane-induced hypoxemia. Changes characterizing the autonomic responsiveness to urethane stimuli in mice are described and should be considered when choosing the appropriate anesthetic agent. NIH1R21HD099573 and NIH 1R56HL152365. This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.