Effects of housing temperature on stress‐induced hyperthermia in mice, and the associated change in voluntary motor activity (1105.1)

Abstract

Many studies that investigate stress‐induced hyperthermia (SIH) in rodents were conducted on mice housed under ambient temperatures (Ta) of 20‐22°C, which can induce chronic stress due to cold exposure. Further, SIH in mice is associated with an increase in voluntary motor activity (VMA). Given that VMA can be affected by Ta and that VMA can be a major source of heat production, we hypothesized that the amplitude of SIH, and the relationship between SIH and VMA, is affected by Ta. Two groups of 8 male mice, housed either at 21 or 27°C, were exposed to treatments known to induce varying levels of stress. For both groups. the treatments resulted The treatments for both groups resulted in an increasing SIH (control<handling<water spill<cage switch<clean cage) that was correlated to VMA; the slopes of the relationship between SIH and VMA did not differ between groups. The absolute amplitude of SIH of mice housed at 27ºC was significantly higher (by 0.45°C) than mice housed at 21°C, but the relative amplitude (during ‐ before stress) did not differ between groups. Within the range of Ta studied, we conclude that housing temperatures have minor effects on the stress response of mice.Grant Funding Source: Supported by a CSU‐AAUP grant