The effects on heart rate and temperature of mice and vas deferens responses to noradrenaline when their cage mates are subjected to daily restraint stress

Abstract

Performing stressful procedures in view of cage mates may cause stress in observer animals. However, it is not known if stressful procedures performed in close proximity to, but not in view of cage mates are stressful for the (observer) cage mates. Radiotelemetry and postmortem in vitro studies of the vas deferens were used to determine the effects of stress on observers. Heart rate (HR) and core body temperature (cBT) were recorded for 1 h following weighing of a cage mate or 1 h during restraint of a cage mate and the hour following return of the restrained mouse to the cage. This procedure was repeated daily for 15 days. HR and cBT were increased in observers during both restraint and weighing of cage mates. Analysis of the area under the curve showed that HR and cBT in observers were significantly higher during restraint of a cage mate than after weighing of a cage mate. When mice were returned to the cage after weighing or restraint, HR and cBT were significantly higher in the cage mates of restrained animals. Comparison between days 1, 3, 7 and 14 found that, as the experiment progressed, HR and cBT were significantly reduced in the observer mice during the hour following return of the cage mates after restraint. Results from previous studies have shown that chronic stress causes the vas deferens to become hypersensitive to exogenous application of noradrenaline (NAd). In this study, vas deferens from observers of restraint had a significantly increased response to NAd. These results indicate that stressful procedures should be conducted in isolation from other mice.

Benefits of non-invasive methods compared to telemetry for distress analysis in a murine model of pancreatic cancer

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“…Heart rate is often used as a measure of stress (Bernberg et al, 2009; Gilmore et al, 2008; Meijer et al, 2009) and was therefore chosen for evaluation in our study. Our results confirm previous studies that demonstrated reduced heart rate with increased housing density (Nicholson et al, 2009; Van Loo et al, 2007).…”

A Review of Pain Assessment Methods in Laboratory Rodents

“…118,121 Similarly, other variables that can cause significant and persistent perturbations in heart rate and blood pressure include routine cage changes, social housing, various experimental manipulations, and the provision of in-cage resources, such as running wheels. 1,43,65,127,133 Therefore, remote assessment of variables such as heart rate, respiratory rate, body temperature, and blood pressure is preferable, whenever possible. This can be achieved through telemetry, and some physiologic parameters, such as respiratory and heart rates, can even be measured by automated 'smart caging'.…”