Physical stimulation reduces the body temperature of infant rats

Abstract

Physical stimulation of rat pups, of the type normally received from the mother, has been shown to regulate several behavioral and physiological systems in the young. The present paper describes a possible role of physical stimulation in an additional physiological system; the thermoregulatory system. Within a thermoneutral environment, physical stimulation produces a decrease in rectal temperature (Expt. 1). Even in an environment of increasing temperature, similar to that pups experience when in contact with the dam, physical stimulation attenuates an increase in rectal temperature (Expt. 2). The physiological mechanism of heat loss appears to involve ventilatory heat exchange resulting in convective and evaporative heat loss (Expts. 3, 4). Furthermore, physical stimulation continues to produce a decrease in rectal temperature throughout the preweanling period (Expt. 5). These results suggest that pups may not always have to resort to behavioral thermoregulatory mechanisms which require them to separate themselves from their mother. Rather, pups may be cooled, or at least a heat gain attenuated, by physical stimulation from the dam while maintaining contact with her.

Maternal licking regulates hippocampal glucocorticoid receptor transcription through a thyroid hormone–serotonin–NGFI-A signalling cascade

“…The present findings suggest that an increased frequency of pup LG typical of High-LG mothers associates with an increased conversion of the T4 precursor to the more active T3 in BAT (figure 2c). Interestingly, pup LG produces a modest but physiologically relevant decrease in pup body temperature [38], which commonly associates with increased sympathetic activity. Sympathetic activation of BAT stimulates the conversion of T4 to T3 [39].…”

Neuroethology of olfactory preference development

“…We therefore paired the odor with high humidity, which does not evoke an increase in respiration, and tested for a behavioral preference and an enhanced glomerular response to the odor on day 19. We found that pups acquired a preference and an enhanced glomerular response to the conditioned odor without an increase in respiration during training (Sullivan et al, 1988b). Therefore, differential respiration of the odor during early olfactory preference conditioning is not critical for development of the altered neurobehavioral response (Do, Sullivan, and Leon, 1988).…”

Critical analysis of potential body temperature confounders on neurochemical endpoints caused by direct dosing and maternal separation in neonatal mice: a study of bioallethrin and deltamethrin interactions with temperature on brain muscarinic receptors

“…Despite this relative immaturity, however, these pups exhibit a fair degree of thermoregulatory competence within the context of their normal environment-the litter situation. For example, pups exhibit thermotaxis, seeking out both the warm dam and the litter (Sullivan et al, 1988). The objective of the present investigation was to understand better some of the possible confounding factors caused by direct dosing of pups during the pre-weaning developmental period.…”

“…Any extended disruption of the social relationship of dams and pups as a result of dosing and/or direct effects caused by the administered substance would be expected to be associated with a fall in the body temperatures of pups. Sullivan et al (1988) have shown that the mere physical stimulation of rat pups (stroke and shake, of the type normally received from the mother) affects the regulation of several behavioural and physiological systems of the young. Especially for neonatal mice-an altricial species-the thermoregulatory status is exceptionally dynamic and changes rapidly and profoundly during postnatal ontogenesis from poikilothermic to homeothermic.…”