Ret 3 mouse rectal probe

Mice were individually housed at 4°C for 8 h without food but with free access to water. Rectal temperature was measured every hour with a BAT-12 microprobe digital thermometer and RET-3 mouse rectal probe (Physitemp Instruments, Clifton, USA).

Body composition (fat mass, lean mass and fluid) was assessed by using a magnetic resonance whole-body composition analyzer (Minispec LF90 II, Bruker, Karlsruhe, Germany). Oxygen consumption, carbon dioxide production and locomotor activity were measured using a sixteen-chamber indirect calorimeter (TSE PhenoMaster) according to the manufacturer’s instructions [56 (link)]. The mice were maintained at 22 °C under a 12 h light-dark cycle following a 12 h acclimatization. To obtain metabolic parameters under cold stimuli, mice were intraperitoneally injected with the β3-adrenergic receptor-specific agonist CL316,243 (1 mg/kg) after a 12 h light/dark cycle. The mice were given free access to water and food. Heat production as name as energy expenditure, oxygen expenditure and activity were calculated as described previously. For cold exposure, mice were single-caged and exposed to a temperature of 4 °C for 6 h. Rectal temperature was monitored every hour using a BAT-12 microprobe digital thermometer and RET-3 mouse rectal probe (Physitemp Instruments, Clifton, NJ, USA). Thermo images were taken using an E6 Thermal Imaging Infrared Camera (E6, FLIR Systems, Portland, OR, USA) at 6 h, and the interscapular skin temperature was analyzed using FLIR Tools software.

Rectal temperature was measured using a BAT-12 Microprobe digital thermometer with a RET-3 mouse rectal probe (Physitemp Instruments, Clifton, New Jersey). Mice (2–4-month-old) were gently restrained, and the lubricated probe was inserted 1.5 cm into the rectal cavity to determine body temperature.

For chronic cold exposure, mice were singly housed at 4°C for 24 h. Food and water were available ad libitum. For acute cold exposure, mice were individually housed at 4°C for 8 h without food but with free access to water. Body temperature was measured every hour with a BAT-12 microprobe digital thermometer and RET-3 mouse rectal probe (Physitemp Instruments, Clifton, USA).

A BAT-12 Microprobe digital thermometer and RET-3 mouse rectal probe (Physitemp Instruments, Clifton, NJ, USA) were used to obtain rectal core temperatures to a precision of +/-0.1°C, as previously described
[8 (link)]. Care was taken to measure temperatures ≥2 days after cage bedding changes, and to avoid animal transport stress immediately prior to measurement in order to avoid stress-induced hyperthermia
[23 (link)]. Temperatures were measured between 09:00 and 12:00 each day.

Mice were individually housed at 4 °C for 7 h without food but with free access to water. Rectal temperature was measured every hour with a BAT-12 microprobe digital thermometer and RET-3 mouse rectal probe (Physitemp Instruments, Clifton, USA). Thermo-images were taken using an E6 Thermal Imaging Infrared Camera (FLIR Systems) and the skin temperature were analyzed using FLIR Tools software.