Stress-induced hyperthermia in the rat: comparison of classical and novel recording methods

Abstract

SummaryStress causes a rise in body temperature in laboratory animals (stress-induced hyperthermia). However, the direct effect of common stressors in animal research, i.e. transportation between holding and test rooms or isolation of animals, on body temperature has not been investigated to its full extent. To address this question, it is important to have a reliable and simple monitoring technique, which does not induce stress itself. In the present study, we investigated stress-related changes in body temperature of F344/Hw rats after (1) moving the cage within the holding room, (2) moving the cage from the holding room to another test room and (3) social deprivation (isolation). A combination of two different body temperature recording methods was used to clarify their accuracy and stress-inductive character: rectal temperature recording and peritoneal implanted temperature sensors (Thermochron iButtons).The results demonstrate that (1) different stressors induce a significant rise in body temperature, (2) which is detectable for more than 60 min and (3) it is of importance to standardize temperature recording methods in order to avoid confounding effects of the recording method itself. Furthermore, Thermochron iButtons are more accurate and reliable for body temperature studies than rectal recordings.

Breathing and temperature control disrupted by morphine and stabilized by clonidine in neonatal rats

“…Because both saline and clonidine animals moved about freely in the chamber it is doubtful that clonidine, at the dosages used, induced excessive sedation to account for the differences in CBT. We speculate that the increase in temperature observed in the saline treated animals by 60 minutes could be related to increase stress (Dallmann et al 2006, Ito et al 2006). …”

“…Thus, clonidine at all dosages and morphine at moderate dosages maintained CBT, however morphine at the highest dose induced hypothermia, decreasing CBT by ~ 3 degrees by 90 min after administration in newborn rats (Figure 6a, 6b). We speculate that the increase in CBT observed in the saline treated animals might be stress induced since the pups were removed from the mother and placed in a novel environment (Dallmann et al 2006, Ito et al 2006, Yee et al 2011). Although not systematically measured, both clonidine and saline animals had similar levels of activity, thus, it is less likely that exploring a novel environment is the etiology for the differences in temperature elevation.…”

Methamphetamine-Induced Behavioral and Physiological Effects in Adolescent and Adult HIV-1 Transgenic Rats

“…Handling and habituation procedures can reduce or eliminate environmental modulation of behavior and, importantly, without affecting the development of stimulant-induced BS (Crombag et al 2001). For instance, the rectal probe thermometry-induced hyperthermia can be eliminated with only 60-min of habituation (Dallmann et al 2006). Our preliminary studies also demonstrated that a 2-day adaptation period was sufficient in reducing stress-induced hyperthermia.…”

EMF radiation at 2450MHz triggers changes in the morphology and expression of heat shock proteins and glucocorticoid receptors in rat thymus

“…Rectal temperatures were measured in order to evaluate how radiation, a stimuli that may trigger thermal stress, affected hypothalamic adjustments to the thermoregulatory mechanisms [7,16]. Temperature was measured with a digital thermometer (Eutech Instruments) immediately before placing the animal in the radiation chamber immediately after exposure (0 m) and at 30 m, 90 m and 24 h post irradiation (time of sacrifice).…”