Evidence of environmental influence on the development of thermoregulation in the rat

Abstract

Sprague-Dawley rats were raised in an environmentally controlled room at 33 degrees C. Thermoregulatory responses of animals reared in this way were compared with those of control and warm-acclimated rats. Warm-reared animals demonstrated a significantly greater fall in colonic temperature during cold exposure when compared with both warm-acclimated (p less than 0.01) and control (p less than 0.001) animals. Warm-reared animals also show a modified response to central infusion of noradrenaline; they produce a hyperthermia in contrast with the hypothermia observed in control and warm-acclimated rats. These results suggest that the early thermal environment may modify the development of temperature regulation in the Sprague-Dawley rat in a way different from the normal acclimation process.

Facial thermal input in the caudal trigeminal nucleus of rats reared at 30 degrees C.

“…We have confirmed the observations of Ferguson et al (1981) that rats show an inability to thermoregulate in the cold if raised in the heat. The thermal afferent system in treated and normal rats was studied at the level of the trigeminal nucleus.…”

“…Rats reared at 33 uC have been shown by Ferguson et al (1981) to be unable to maintain rectal temperature during a 4 hr exposure to 2 0C, whereas animals reared at 20 0C remained in thermal balance. Similarly, our results show that rats reared at 30 sC have a considerably reduced capacity to thermoregulate when exposed to TRLIEMINAL THERMAL INPUT IN HEAT-REARED RATS 10 0C compared to controls reared at 20 0C.…”

“…When rabbits or rats are born and allowed to develop in a hot environment they are unable to maintain their body temperature when challenged by exposure to a cold environment in which control animals reared at 20 'C can thermoregulate without difficulty (Cooper, Ferguson & Veale, 1980;Ferguson, Veale & Cooper, 1981). Part of the deficiency may lie in a failure of the afferent pathways from the skin thermal receptors to develop normally.…”

Neonatal Programming of Body Weight Regulation and Energetic Metabolism

“…The sympathetic innervations of peripheral tissues and the responsiveness of sympathetic nerves and adrenal medulla to standard stimuli are susceptible to modification by exposures in early life, such as environmental temperature, nutrition and stress. Effects of temperature exposure in early life on thermoregulation appear to be qualitatively different from those of cold and heat acclimatization in adult animals (Ferguson et al, 1981).…”

Rearing mice at 22°C programs increased capacity to respond to chronic exposure to cold but not high fat diet

“…Exposure to lower temperatures in the early postnatal period enhances cold responsiveness in humans [ 8 ], sheep [ 9 ], rabbits [ 10 ], rats [ 11 ] and mice [ 12 ]. In rodent models, effects of cold exposure during early development on thermogenic capacity persist to adulthood [ 11 , [13] , [14] , [15] ], while they only last a few weeks when T a is manipulated in adulthood [ 11 , 13 , 16 ].…”